Showing papers in "Medical Microbiology and Immunology in 2009"
TL;DR: The results of several recent proof-of-principle studies are reviewed that open the exciting perspective of using sdAbs for modulating immune functions and for targeting toxins and microbes.
Abstract: Antibodies are important tools for experimental research and medical applications. Most antibodies are composed of two heavy and two light chains. Both chains contribute to the antigen-binding site which is usually flat or concave. In addition to these conventional antibodies, llamas, other camelids, and sharks also produce antibodies composed only of heavy chains. The antigen-binding site of these unusual heavy chain antibodies (hcAbs) is formed only by a single domain, designated VHH in camelid hcAbs and VNAR in shark hcAbs. VHH and VNAR are easily produced as recombinant proteins, designated single domain antibodies (sdAbs) or nanobodies. The CDR3 region of these sdAbs possesses the extraordinary capacity to form long fingerlike extensions that can extend into cavities on antigens, e.g., the active site crevice of enzymes. Other advantageous features of nanobodies include their small size, high solubility, thermal stability, refolding capacity, and good tissue penetration in vivo. Here we review the results of several recent proof-of-principle studies that open the exciting perspective of using sdAbs for modulating immune functions and for targeting toxins and microbes.
565 citations
TL;DR: This review describes how Brucella strains have efficiently adapted to their intracellular lifestyle in the host and leads to the chronic infections that are a hallmark of brucellosis in both natural hosts and humans.
Abstract: Brucella strains produce abortion and infertility in their natural hosts and a zoonotic disease in humans known as undulant fever. These bacteria do not produce classical virulence factors, and their capacity to successfully survive and replicate within a variety of host cells underlies their pathogenicity. Extensive replication of the brucellae in placental trophoblasts is associated with reproductive tract pathology in natural hosts, and prolonged persistence in macrophages leads to the chronic infections that are a hallmark of brucellosis in both natural hosts and humans. This review describes how Brucella strains have efficiently adapted to their intracellular lifestyle in the host.
186 citations
TL;DR: S-O IV should be taken seriously as pandemic threat and underestimation of the menace by S-OIV to be by far more dangerous than its overestimation, the authors are convinced.
Abstract: Influenza A viruses represent a continuous pandemic threat. In April 2009, a novel influenza A virus, the so-called swine-origin influenza A (H1N1) virus (S-OIV), was identified in Mexico. Although S-OIV originates from triple-reassortant swine influenza A (H1) that has been circulating in North American pig herds since the end of the 1990s, S-OIV is readily transmitted between humans but is not epidemic in pigs. After its discovery, S-OIV rapidly spread throughout the world within few weeks. In this review, we sum up the current situation and put it into the context of the current state of knowledge of influenza and influenza pandemics. Some indications suggest that a pandemic may be mild but even "mild" pandemics can result in millions of deaths. However, no reasonable forecasts how this pandemic may develop can be made at this time. Despite stockpiling by many countries and WHO, antiviral drugs will be limited in case of pandemic and resistances may emerge. Effective vaccines are regarded to be crucial for the control of influenza pandemics. However, production capacities are restricted and development/production of a S-OIV vaccine will interfere with manufacturing of seasonal influenza vaccines. The authors are convinced that S-OIV should be taken seriously as pandemic threat and underestimation of the menace by S-OIV to be by far more dangerous than its overestimation.
120 citations
TL;DR: This review summarizes current knowledge about the relation ofNETs in a broad spectrum of clinical settings and focuses on the importance of NETs as a predictive marker in severely ill patients and further, speculate about the potential pathophysiology of Nets.
Abstract: Neutrophil extracellular traps (NETs) have recently been discovered as a central part of antimicrobial innate immunity. In the meanwhile, evidence accumulated that NETs are also generated upon non-infectious stimuli in various clinical settings. In acute or chronic inflammatory disorders aberrantly enhanced NET formation and/or decreased NET degradation seems to correlate with disease outcome. This review summarizes current knowledge about the relation of NETs in a broad spectrum of clinical settings. Specifically, we focus on the importance of NETs as a predictive marker in severely ill patients and further, we speculate about the potential pathophysiology of NETs.
115 citations
TL;DR: There is considerable evidence supporting the notion that generation of a vaccine is feasible, and a vaccine against M. ulcerans would protect persons at risk in highly endemic areas and could be used as a therapeutic vaccine to shorten the duration of treatment and prevent relapses.
Abstract: Buruli ulcer disease (BUD), caused by Mycobacterium ulcerans, is a neglected bacterial infection of the poor in remote rural areas, mostly affecting children. BUD is a mutilating disease leading to severe disability; it is the third most common mycobacterial infection in immunocompetent people after tuberculosis and leprosy. It is most endemic in West Africa, but cases have been reported from more than 30 countries. Treatment with antibiotics is possible, long-lasting and requires injections; there are cases of treatment failures, and the disease is prone to resistance. A vaccine against M. ulcerans would protect persons at risk in highly endemic areas, and could be used as a therapeutic vaccine to shorten the duration of treatment and prevent relapses. There is considerable evidence supporting the notion that generation of a vaccine is feasible. This article reviews the present state of the art with special emphasis on the immunology of the infection and the prospects for development of a vaccine.
72 citations
TL;DR: The annual influenza vaccination in children and adolescents may improve considerably the protection against influenza virus infection occurring during epidemics.
Abstract: The objective of this study was to provide seroepidemiological information on influenza A and B antibodies in children and adolescents. Viral immunoglobulin G antibodies were determined retrospectively using enzyme-linked immunosorbent assays in a group of 1,111 children and adolescents. Sera (809) from healthy adult blood donors served as controls. In children, the prevalence of antibodies against influenza A was 82.0% and against influenza B 9.6%, whereas in adults the prevalence of antibodies against influenza A was calculated as 99.4% and against influenza B 56.7%. After decline of maternal antibodies during the first year of life, there was an increase of prevalence of influenza A antibodies up to 100% by the age of 12 years. In contrast, only 1–2% of children up to 9 years had influenza B antibodies increasing to 25% by the age of 18 years and to 70% among adults aged 30 years. Children aged 0–6 years had significantly lower concentrations and >12–15-year-old adolescents had significantly higher concentrations of antibodies against influenza A than adults. For all age groups of children and adolescents, significantly lower antibody concentrations against influenza B were measured in comparison to the blood donor control group. In conclusion, the annual influenza vaccination in children and adolescents may improve considerably the protection against influenza virus infection occurring during epidemics.
52 citations
TL;DR: This work investigated the influence of 3OC12-HSL on cell viability, apoptosis, intracellular calcium and cytokine release in MCs, and found that at high concentrations (100 μM), 3OC 12- HSL inhibited proliferation and induced apoptosis in P815 and HMC-1.
Abstract: Quorum sensing system is a cell-to-cell communication system that plays a pivotal role in virulence expression in bacteria. Recent advances have demonstrated that the Pseudomonas aeruginosa quorum sensing molecule, N-3-oxododecanoyl homoserine lactone (3OC(12)-HSL), exerts effects on mammalian cells and modulates host immune response. Mast cells (MCs) are strategically located in the tissues that are constantly exposed to external stimulus. Therefore, it is very much possible that 3OC(12)-HSL may interact with MCs. Little is known, however, about specific effects of 3OC(12)-HSL on MCs. To address this, we investigated the influence of 3OC(12)-HSL on cell viability, apoptosis, intracellular calcium and cytokine release in MCs. We found that at high concentrations (100 microM), 3OC(12)-HSL inhibited proliferation and induced apoptosis in P815. The 3OC(12)-HSL treatment significantly increased intracellular calcium release in both P815 and HMC-1. We also observed that 3OC(12)-HSL-induced histamine release and degranulation in HMC-1 cells. Furthermore, 3OC(12)-HSL-induced IL-6 production at lower concentrations (6.25-12.5 microM) but steadily reduced IL-6 production at high concentration (50-100 muM). These data demonstrate that P. aeruginosa 3OC(12)-HSL affects MCs function.
52 citations
TL;DR: Recent pathological Wndings from diVerent groups using highly sensitive techniques for virus detection indicated the presence of genome and antigens of HCMV in tumour cells (but not in adjacent normal tissue) of a great proportion of patients with malignancies.
Abstract: The human cytomegalovirus (HCMV), a ubiquitous herpes virus, establishes after (in healthy individuals typically subclinical) primary infection a lifelong persistence characterised by more or less frequent subclinical reactivations. It is an important pathogen in immunocompromised individuals and currently investigated for a plethora of diVerent questions and aspects [1–25]. The (possible) relationship between HCMV and cancer has been discussed for decades [1]. Detection of viral DNA, mRNA and/or antigens in tumour tissues as well as seroepidemiologic evidence suggested a role of HCMV infection in several human malignancies. However, controversial clinical results from diVerent groups had raised skepticism about a role of HCMV in cancer [1]. A major point of concern is that HCMV is not considered to be a tumour virus due to a lack of proven transformation potential in human cells. To explain the frequent presence of HCMV in tumour tissues, we proposed the concept of oncomodulation [26]. Oncomodulation means that HCMV may infect tumour cells and increase their malignancy. We postulated that tumour cells provide a genetic environment, characterised by disturbances in intracellular signalling pathways, transcription factors, and tumour suppressor proteins, that enables HCMV to exert its oncomodulatory potential while it cannot be manifested in normal cells (Fig. 1) [1]. Our experimental Wndings and those of others supported the concept of oncomodulation. Sub-cutaneous injection of long-term persistently HCMV-infected neuroblastoma cells resulted in enhanced tumour growth and metastasis formation compared to non-infected cells [26]. Subsequent in vivo Wndings by others supported the oncomodulatory eVects of HCMV or murine cytomegalovirus proteins expressed in transformed cells [1]. HCMV-induced oncomodulation may result from the activity of virus regulatory proteins and noncoding RNAs which inXuence properties of tumour cells including cell proliferation, survival, invasion, immunogenicity, tumour angiogenesis, and chromosomal stability [1]. Although it is necessary to stress that no Wnal conclusion about the (frequency of the) presence of HCMV in cancer cells and its eVects on tumour biology can be drawn, recent pathological Wndings from diVerent groups using highly sensitive techniques for virus detection indicated the presence of genome and antigens of HCMV in tumour cells (but not in adjacent normal tissue) of a great proportion of patients with malignancies, such as colon cancer, malignant glioma, prostatic carcinoma, and breast cancer [1, 27–30]. These observations indicated that HCMV causes low-grade infection in tumour cells probably sustained by persistent virus replication. The establishment of low-grade infection by HCMV in tumour cells provides an explanation why HCMV was not detected in tumour cells by diVerent other groups [1, 31– 33]. These groups used pathological methods established for the detection of active HCMV replication, characterised by high HCMV titres and presence of high levels of HCMV proteins and HCMV genome that obviously fail to detect low-level replication. It might be helpful to exemplarily discuss pathological Wndings from glioma patients. Cobbs et al. [27] reported HCMV infection of tumour cells but not of surrounding normal brain tissue in a high percentage of gliomas. These Wndings were not conWrmed by Lau et al. [31] or Polterman et al. [32], who both did not detect M. Michaelis · H. W. Doerr · J. Cinatl Jr (&) Institut für Medizinische Virologie, Klinikum der Johann Wolfgang Goethe-Universität, Paul Ehrlich-Str. 40, 60596 Frankfurt am Main, Germany e-mail: cinatl@em.uni-frankfurt.de
47 citations
TL;DR: Antigen specific IgG subclass analysis showed that rBCG::Ag85B-Rv3425 tended to facilitate IgG2a production, suggesting enhancement of predominant Th1 response which in turn may facilitate increased production of protective IFN-γ.
Abstract: Antigen 85B (Ag85B) is an important immunodominant antigen of Mycobacterium tuberculosis, and is a very promising vaccine candidate molecule. Rv3425 is a member of the subgroup 3 of the PPE family, which does not exist in all BCG strains. In this study we constructed a new rBCG which included this united gene (Ag85B-Rv3425). The level of antigen-stimulated T cells expressing IFN-γ was significantly higher in the C57BL/6 mice vaccinated with rBCG::Ag85B-Rv3425 than with BCG. In addition, the sera from mice immunized with rBCG::Ag85B-Rv3425 revealed an increase in the specific immunoglobulin G titers than that from mice immunized with BCG. Antigen specific IgG subclass analysis showed that rBCG::Ag85B-Rv3425 tended to facilitate IgG2a production, suggesting enhancement of predominant Th1 response which in turn may facilitate increased production of protective IFN-γ. These results suggested that this rBCG::Ag85B-Rv3425 could be a strong vaccine candidate for further study.
45 citations
TL;DR: The PUUV seroprevalence in the residents of the outbreak region in Lower Bavaria was found to be up to fivefold higher than the average hantavirus serop revalence of the German population.
Abstract: Puumala virus (PUUV) is the cause of the majority of haemorrhagic fever with renal syndrome cases in Germany. In 2004, a nephropathia epidemica outbreak was recorded in Lower Bavaria, South-East Germany. For a seroepidemiological study in this region including the resident population at four locations (n = 178) and soldiers from one location (n = 208) indirect immunoglobulin M (IgM) and immunoglobulin G (IgG) enzyme-linked immunosorbent assays (ELISAs) and immunoblot tests based on a yeast-expressed PUUV nucleocapsid protein were established. The validation using human serum panels originating from Germany revealed a diagnostic sensitivity and specificity of 98/100% for the IgM ELISA, 99/99% for the IgG ELISA, 99/100% for the IgM immunoblot test and 100/96% for the IgG immunoblot test. Using the novel IgG assays as well as a commercial IgG ELISA and an immunofluorescence assay for the resident population an average prevalence of 6.7% (12 of 178) with a range of 0% (0 of 21) to 11.9% (7 of 59) was observed. Positive serological results were equally distributed between males and females with an average age of 63 for males and 52 for females. The seroprevalence in the soldier group was found to be about 1% with one positive male of 203 (age 46 years) and one positive female of five (age 47 years). In conclusion, the PUUV seroprevalence in the residents of the outbreak region in Lower Bavaria was found to be up to fivefold higher than the average hantavirus seroprevalence of the German population.
38 citations
TL;DR: BLf, iron- or zinc-saturated BLf is one of the candidates for anti-HBV reagents in treatment of patients with hepatitis and suggests that BLf inhibits the function of HBV by integrated structure.
Abstract: In this study, we investigated the effect of bovine lactoferrin (BLf), lactoferrin hydrolysate, or iron-, zinc-saturated lactoferrin on hepatitis B virus (HBV)-infected HepG2 cells. Fluorescent quantitative polymerase chain reaction (FQ-PCR) was used to quantify HBV-DNA copies. BLf, iron- or zinc-saturated lactoferrin significantly inhibited the amplification of HBV-DNA in a dose-dependent manner in HBV-infected HepG2 cells. However, the inhibitive effect of lactoferrin hydrolysate on HBV-DNA copies was insignificant. These findings suggest that BLf inhibits the function of HBV by integrated structure. In conclusion, BLf, iron- or zinc-saturated BLf is one of the candidates for anti-HBV reagents in treatment of patients with hepatitis.
TL;DR: The disease is described in a German traveller who was not aware of the prevalence of this infection in his holiday destination, the Northern Territory and Queensland, Australia, and presented with chills, watery diarrhoea and severe, prolonged arthritis.
Abstract: Ross River virus is an arthropod-borne alphavirus (family Togaviridae) causing epidemic polyarthritis in the Australia-Pacific region. The infection causes substantial morbidity due to long-lasting arthralgia. Despite being the most common arboviral infection in Australia, reports in travellers are scarce. Here, we describe the disease in a German traveller who was not aware of the prevalence of this infection in his holiday destination, the Northern Territory and Queensland, Australia. The patient had neither fever nor rash, but presented with chills, watery diarrhoea and severe, prolonged arthritis.
TL;DR: This work highlights how the skin utilizes different strategies to prevent skin infection and how containment of the infection to the skin site may reduce the harm that otherwise may result for the entire organism.
Abstract: Most parasitic skin infections are averted by very efficient strategies of preventing pathogen invasion. Innate immune cells such as mast cells, macrophages and dendritic cells are responsible for detecting parasites and for recruiting proinflammatory cells that help to contain and control the pathogen at sites of infection. This induces efficient adaptive immunity, which is crucially important for parasite control. Using the example of cutaneous leishmaniasis, we highlight how the skin utilizes different strategies to prevent skin infection and how containment of the infection to the skin site may reduce the harm that otherwise may result for the entire organism.
TL;DR: The sensitivity of T-SPOT appeared to be higher than that of QFT-G, whereas the specificity of T -SPOT was significantly lower than thatof Q FT-G and biological relevance of each system in diagnosing M. tuberculosis infection should be further explored.
Abstract: Performance of two diagnoses, T-SPOT®.TB (T-SPOT) and QuantiFERON-TB® Gold (QFT-G), was compared in Japanese subjects. Forty-seven confirmed tuberculosis patients and eighty-four healthy subjects were recruited. All samples were assessed for both T-SPOT and QFT-G, and the sensitivities and the specificities were compared between two methods. The sensitivity was 100% for T-SPOT, and 87.2% for QFT-G. The specificity was 83.3 and 98.8%, respectively. The overall agreement of two tests was substantially high (Kappa coefficient = 0.671). The sensitivity of T-SPOT appeared to be higher than that of QFT-G, whereas the specificity of T-SPOT was significantly lower than that of QFT-G. The difference in the performance between T-SPOT and QFT-G and biological relevance of each system in diagnosing M. tuberculosis infection should be further explored.
TL;DR: The presence of HLA-A2 elicits a stronger cytotoxic response, which is involved in the HTLV-1 proviral load reduction, and a tendency of this allele to protect against HAM-TSP was confirmed.
Abstract: The development of HTLV-1-associated myelopathy (HAM/TSP) in HTLV-1-infected individuals is probably a multi-factor event, in which the immune system plays a crucial role. The efficiency of the host immunity seems to be one of the in vivo determining factors of the proviral load levels and is regulated by genes associated with MHC class I alleles (HLA). Protection or predisposition to HTLV-1-associated diseases according to individual HLA profile was shown in Japanese studies. The present work tested for HLA alleles previously related to protection or susceptibility to HTLV-1-associated myelopathy in a cohort study (GIPH) from Brazil. A total of 93 HTLV-1-infected individuals participated in the study, as follows: 84 (90.3%) asymptomatic and 9 (9.7%) with HAM/TSP. Alleles related to protection (A*02, Cw*08) and susceptibility (B*07, Cw*08 and B*5401) were tested by the PCR-SSP method. Allele A*02 was more frequent in the asymptomatic group and in its absence, Cw*07 was correlated with HAM/TSP (P = 0.002). Allele B*5401 was not present in the Brazilian population. Alleles B*07 and Cw*08 were not different between the groups The presence of HLA-A2 elicits a stronger cytotoxic response, which is involved in the HTLV-1 proviral load reduction. This study confirmed a tendency of this allele to protect against HAM-TSP. Therefore, A*02 might be of interest for researches involved with HTLV-1 vacine.
TL;DR: The results suggest that HBV compromises the innate immune system in HCC patients and that inhibition of HBV replication by siRNAs may enhance the antitumor immune response.
Abstract: Hepatitis B virus (HBV) replicates in most tumor tissues of patients with HBV-associated hepatocellular carcinoma (HCC). In the present study, we have shown that the expression of HBV in the HCC cell lines, HepG2 and Huh7, down-regulated the expression of MHC class I-related molecule A (MICA), a ligand of the NKG2D receptor. Inhibition of HBV expression by small interference RNAs (siRNAs) in HepG2.2.15, a cell line that constitutively expresses HBV, induced up-regulation of MICA. The up-regulation of MICA increased the lysis of HepG2.2.15 cells by NK cells. Our results suggest that HBV compromises the innate immune system in HCC patients and that inhibition of HBV replication by siRNAs may enhance the antitumor immune response.
TL;DR: There are beneficial aspects in the response of the scientific community to the HIV burden for the management of other viral diseases and these aspects are described in this contribution.
Abstract: The human immunodeficiency virus (HIV) had spread unrecognized in the human population as sexually transmitted disease and was finally identified by its disease AIDS in 1981. Even after the isolation of the causative agent in 1983, the burden and death rate of AIDS accelerated worldwide especially in young people despite the confection of new drugs capable to inhibit virus replication since 1997. However, at least in industrialised countries, this trend could be reversed by the introduction of combination therapy strategies. The design of new drugs is on going; besides the inhibition of the three enzymes of HIV for replication and maturation (reverse transcriptase, integrase and protease), further drugs inhibits fusion of viral and cellular membranes and virus maturation. On the other hand, viral diagnostics had been considerably improved since the emergence of HIV. There was a need to identify infected people correctly, to follow up the course of immune reconstitution of patients by measuring viral load and CD4 cells, and to analyse drug escape mutations leading to drug resistance. Both the development of drugs and the refined diagnostics have been transferred to the treatment of patients infected with hepatitis B virus (HBV) and hepatitis C virus (HCV). This progress is not completed; there are beneficial aspects in the response of the scientific community to the HIV burden for the management of other viral diseases. These aspects are described in this contribution. Further aspects as handling a stigmatising disease, education of self-responsiveness within sexual relationships, and ways for confection of a protective vaccine are not covered.
TL;DR: It is suggested that NO has an important role in granuloma modulation, by controlling OPN and MMP production, as well as by inducing loose granulomas formation and fungal dissemination, resulting, at later phases, in progression of paracoccidioidomycosis.
Abstract: The role of nitric oxide (NO) in granulomas of Paracoccidioides brasiliensis-infected inducible NO synthase-deficient C57BL/6 mice (iNOS KO) and their wild-type counterparts and its association with osteopontin (OPN) and matrix metalloproteinases (MMPs) was studied. At 15 days after infection (DAI), iNOS KO mice showed compact and necrotic granulomas with OPN+ macrophages and multinucleated giant cells, whereas wild-type mice developed loose granulomas with many fungi and OPN+ cells distributed throughout the tissue. In addition, high OPN levels and fungal load were observed in iNOS KO mice. Both experimental groups had MMP-9 activity. At 120 DAI, iNOS KO had smaller granulomas with OPN+ cells, lower OPN levels, lower fungal load and decreased MMP-9 activity compared with wild-type mice. These findings suggest that NO has an important role in granuloma modulation, by controlling OPN and MMP production, as well as by inducing loose granulomas formation and fungal dissemination, resulting, at later phases, in progression of paracoccidioidomycosis.
TL;DR: It is shown that bradykinin and the B2R play a role in early innate immune functions during bacterial infection and potentiates the production of IL-12p70 in human monocyte-derived dendritic cells.
Abstract: The endogenous danger signal bradykinin was recently found implicated in the development of immunity against parasites via dendritic cells. We here report an essential role of the B2 (B2R) bradykinin receptor in the early immune response against Listeria infection. Mice deficient in B2R (B2R−/− mice) were shown to suffer from increased hepatic bacterial burden and concomitant dramatic weight loss during infection with Listeria monocytogenes. Levels of cytokines known to play a pivotal role in the early phase immune response against L. monocytogenes, IL-12p70 and IFN-γ, were reduced in B2R−/− mice. To extend these findings to the human system, we show that bradykinin potentiates the production of IL-12p70 in human monocyte-derived dendritic cells. Thus, we show that bradykinin and the B2R play a role in early innate immune functions during bacterial infection.
TL;DR: The data show that NMB1966 has a role in virulence and that remodelling of the outer membrane and surface/structures is associated with attenuation of the NMB 1966 mutant.
Abstract: We sought to determine whether NMB1966, encoding a putative ABC transporter, has a role in pathogenesis. Compared to its isogenic wild-type parent strain Neisseria meningitidis MC58, the NMB1966 knockout mutant was less adhesive and invasive for human bronchial epithelial cells, had reduced survival in human blood and was attenuated in a systemic mouse model of infection. The transcriptome of the wild-type and the NMB1966 mutant was compared. The data are consistent with a previous functional assignment of NMB1966 being the ABC transporter component of a glutamate transporter operon. Forty-seven percent of all the differentially regulated genes encoded known outer membrane proteins or pathways generating complex surface structures such as adhesins, peptidoglycan and capsule. The data show that NMB1966 has a role in virulence and that remodelling of the outer membrane and surface/structures is associated with attenuation of the NMB1966 mutant.
TL;DR: Elecsys HBsAg II was the most sensitive assay for detecting positive results in seroconversion samples: up to 14, 11, and 22 days earlier than the Architect, AxSYM, and MTPHBsAg assays, respectively.
Abstract: Screening for hepatitis B surface antigen (HBsAg) demands highly sensitive and specific immunoassays with the ability to detect clinically relevant surface gene mutants—the presence of which is an increasing concern and can compromise test results. The objective of the study was to compare the clinical and technical performance of the fully automated Elecsys HBsAg II assay with other widely used HBsAg immunoassays in China. This was a multicentre study in which eight Chinese laboratories compared the Elecsys HBsAg II assay with the Architect HBsAg assay, AxSYM HBsAg assay, or generic microtitre plate (MTP) enzyme-linked immunosorbent assays (manufactured in China) against preselected samples, including recombinant surface gene mutants, and routine clinical samples. Elecsys HBsAg II was the most sensitive assay for detecting positive results in seroconversion samples: up to 14, 11, and 22 days earlier than the Architect, AxSYM, and MTP HBsAg assays, respectively. It also detected all 211 preselected HBsAg-positive specimens and all 13 recombinant HBsAg mutants; the AxSYM and MTP HBsAg assays failed to detect 3 and 10 mutant samples, respectively. Sensitivity was 100% for Elecsys HBsAg II with routine samples, compared with 99.1, 98.9, and 95.2% for the Architect, AxSYM, and MTP HBsAg assays, respectively. In conclusion, it was demonstrated that the Elecsys HBsAg II assay is suitable for routine HBsAg screening in China.
TL;DR: A prudent consequence would be to establish careful survey systems alongside with mass application of new adjuvanted vaccines, or to hold mass vaccination in reserve for use only in situations of true need, such as would arise with the emergence of a more virulent new H1N1 virus strain.
Abstract: Programs for vaccination against the new influenza A/H1N1 targeting many hundred million citizens in Europe and the USA are to be launched in the fall of this year. The USA is planning to employ a non-adjuvanted vaccine, whereas European nations are opting for inclusion of MF59, the adjuvant contained in an alternative seasonal flu vaccine, or the related adjuvant AS03 that is contained in a recently developed H5N1 vaccine. We draw attention to unappreciated hazards of using adjuvanted vaccine in Europe. Evidence from animal experiments in conjunction with clinical epidemiological data indicates that, quite irrespective of cause, stimulation of the immune system may accelerate atherogenesis. Application of adjuvanted flu vaccines to individuals at risk may therefore aggravate the course of underlying atherosclerotic vessel disease with all the clinical consequences. The same may hold true for other widespread diseases that are propelled by deregulated immune mechanisms. Safety trials conducted to date have not specifically taken these possible side effects into account, and unexpected serious adverse effects thus may follow in the wake of a general vaccination program. A prudent consequence would be to establish careful survey systems alongside with mass application of new adjuvanted vaccines, or to hold mass vaccination in reserve for use only in situations of true need, such as would arise with the emergence of a more virulent new H1N1 virus strain, or to use non-adjuvanted vaccines in individuals who are potentially at risk for adverse side effects.
TL;DR: It is demonstrated that incubation of manganese remarkably increased PK-resistances, protein aggregations and β-sheet contents of the PrPs, and the association of the octarepeats number of PrP with mananese may further provide insight into the unresolved biological function of Prp in the neurons.
Abstract: Manganese may play some roles in the pathogenesis of prion diseases. In this study, recombinant human wild-type (WT) PrP and PrP mutants with deleted or inserted octarepeats were exposed to manganese, and their biochemical and biophysical characteristics were evaluated by proteinase K (PK) digestion, sedimentation experiments, transmission electron microscopy and circular dichroism. It demonstrated that incubation of manganese remarkably increased PK-resistances, protein aggregations and β-sheet contents of the PrPs. Moreover, the PrP mutants of inserted or deleted octarepeats were much vulnerable to the influence of manganese, which showed obviously more aggregation and higher β-sheet content than that of WT-PrP. It highlights that the effect of manganese on the PrP seems to lie on the incorrectness of the octarepeats numbers. The association of the octarepeats number of PrP with manganese may further provide insight into the unresolved biological function of PrP in the neurons.
TL;DR: In vivo protective study in BALB/c mice demonstrated the protective efficacy of three B-T constructs against lethal doses of Yersinia pestis till day 20 post challenge, while construct ‘id’ showed partial protection.
Abstract: Capsular F1 and secretory V antigen are the putative vaccine candidates for plague, caused by Yersinia pestis. Contemplating this, we studied the immunogenicity and protective efficacy of collinearly synthesized B- and T-cell epitopes (B-T constructs) of V antigen entrapped in poly (dl-lactide-co-glycolide) microparticles immunized intranasally using single dose immunization schedule in outbred, H-2b and H-2d mice. High antibody levels were observed in terms of IgG, IgA and SIgA peak titers in sera and mucosal washes to different B-T constructs. The constructs ai, bi and fi especially showed high peak antibody titers ranging from 51,200 to 204,000, which were maintained till day 120 post immunization. IgG/IgA Specific activity in sera and washes correlated well with the peak antibody titers. Moreover, all the B-T constructs showed mixed IgG1 and IgG2a/2b response, variable immunoreactivity as well as memory response with V antigen. B-T constructs, viz ai, ak, bi, fi, di and ik showed comparatively high isotype levels. These constructs showed high immunoreactivity, and good recall response with V antigen. Finally, in vivo protective study in BALB/c mice demonstrated the protective efficacy of three B-T constructs (ai, bi and fi) against lethal doses of Yersinia pestis till day 20 post challenge, while construct ‘id’ showed partial protection.
TL;DR: It is suggested that CglD is a virulence factor of E. coli K1 that contributed to the development of neonatal meningitis.
Abstract: Escherichia coli (E. coli) is the most common gram-negative organism causing meningitis during the neonatal period. The mechanism involved in the pathogenesis of E. coli meningitis remains unclear. We previously identified a pathogenicity island GimA (genetic island of meningitic E. coli containing ibeA) from the genomic DNA library of E. coli K1, which may contribute to the E. coli invasion of the blood-brain barrier (BBB). CglD is one of the genes in GimA, and its function remains unknown. In order to characterize the role of cglD in the E. coli meningitis, an isogenic in-frame cglD deletion mutant of E. coli K1 was generated. The results showed that the median lethal dose of the cglD deletion mutant strain was significant higher than that of parent E. coli K1 strain, and the cglD deletion in E. coli K1 prolonged survival of the neonatal rats in experimental meningitis. However, deletion of cglD has no effect on the penetration of E. coli K1 through BBB in vitro and in vivo. Furthermore, our results showed that deletion of cglD in E. coli K1 attenuated cerebrospinal fluid changes, meningeal thickening, and neutrophil infiltration in the cerebral cortex in the neonatal rats with experimental meningitis. Additional results showed that the role of CglD in neonatal meningitis may be associated with its activity of glycerol dehydrogenase. Taken together, our study suggested that CglD is a virulence factor of E. coli K1 contributed to the development of neonatal meningitis.
TL;DR: Formal evidence is given that the absence of human population immunity correlated with a large chikungunya epidemic on Sri Lanka in 2006.
Abstract: A massive outbreak of chikungunya disease occurred on Sri Lanka in 2006. Reasons for the explosive nature of the epidemic are being intensively discussed. According to recognised and anecdotal concepts, absence of human population immunity against chikungunya virus (CHIKV) might have supported virus amplification. However, formal proof of concept is lacking. This study determined the prevalence of anti-CHIKV IgG antibodies as well as CHIKV RNA shortly before the outbreak. Two hundred and six human sera were collected from patients with acute febrile illness in 2004/2005. Validated indirect immunofluorescence and real-time RT-PCR assays for dengue as well as CHIKV were employed. Laboratory evidence of dengue virus infection was seen in 67% of patients, indicating virus activity and exposure to Aedes spp. vectors. These vectors are the same as for chikungunya. However, no evidence of acute or previous chikungunya infection could be demonstrated in the same cohort. This study gives formal evidence that the absence of human population immunity correlated with a large chikungunya epidemic.
TL;DR: The identification of Gag and Nef-specific responses across HIV-1 infected Indian population and targeting epitopes from multiple immunodominant regions may provide useful insight into the designing of new immunotherapy and vaccines.
Abstract: Cytotoxic T lymphocyte (CTL) responses to Gag have been most frequently linked to control of viremia whereas CTL responses to Nef have direct relationship with viral load. IFN-γ ELISpot assay was used to screen CTL responses at single peptide level directed at HIV-1 subtype C Gag and Nef proteins in 30 antiretroviral therapy naive HIV-1 infected Indian individuals. PBMCs from 73.3% and 90% of the study population showed response to Gag and Nef antigens, respectively. The magnitude of Gag-specific CTL responses was inversely correlated with plasma viral load (r = −0.45, P = 0.001), whereas magnitude of Nef-specific responses was directly correlated (r = 0.115). Thirteen immunodominant regions (6 in Gag, 7 in Nef) were identified in the current study. The identification of Gag and Nef-specific responses across HIV-1 infected Indian population and targeting epitopes from multiple immunodominant regions may provide useful insight into the designing of new immunotherapy and vaccines.
TL;DR: The results showed that, in spite of wide individual variability, chronically HCV-infected patients exhibited an extremely high proportion of immune complexed (IC) virus regardless of plasma HCV load and infecting genotype, strengthening the possibility that IC virus could play a critical role in the pathogenesis of HCV infection.
Abstract: In infected individuals, hepatitis C virus (HCV) exists in various forms of circulating particles which role in virus persistence and in HCV resistance to IFN therapy is still debated. Here, the proportion of HCV bound to immunoglobulin was determined in plasma of 107 chronically infected patients harbouring different HCV genotypes and, for comparison, of six patients with acute HCV infection. The results showed that, in spite of wide individual variability, chronically HCV-infected patients exhibited an extremely high proportion of immune complexed (IC) virus regardless of plasma HCV load and infecting genotype. Moreover, no significant association was found between baseline proportion of IC HCV and response to IFN treatment. Plasma samples collected within 2 weeks of treatment from 20 patients revealed a significant decline of mean IC HCV values relative to baseline that clearly paralleled the decay of total HCV load. In acutely infected patients, circulating HCV was not IC or IC at very low levels only in patients developing chronic HCV infection. Collectively, these findings strengthen the possibility that IC virus could play a critical role in the pathogenesis of HCV infection.
TL;DR: In this paper, the authors used flow cytometry to detect human cytomegalovirus (HCMV) infection in infants and concluded that detection of pp65 antigen by FCA is more sensitive for diagnosis of HCMV infection than detection of hCMV-IgM antibody.
Abstract: Human cytomegalovirus (HCMV) can cause symptomatic or asymptomatic infection in infants. One hundred and twenty-six infants were assessed clinically for disease in infantile period. Eighty of them were classified as symptomatic infection on the basis of physical, instrumental, and laboratory findings, 5 were demonstrated by following up to have later developed HCMV disease, and the other 41 infants were classified as asymptomatic infection. HCMV DNA was positive in all urine samples of the symptomatic infants detected by quantitative polymerase chain reaction. HCMV-IgM antibody detected by chemiluminescent immunoassay (CLIA) was positive in 62 of the 85 symptomatic infants, but was negative in all of the samples of asymptomatic infants. HCMV pp65 antigen detected by flow cytometry assay (FCA) was positive in 77 of the 85 symptomatic infants and in none of the asymptomatic infants. The coincidence to symptom of HCMV pp65 antigen detection was higher than those of HCMV DNA and HCMV-IgM antibody detection. The sensitivity, specificity, positive prognostic value and the negative prognostic value of HCMV pp65 antigen detection for diagnosis of HCMV infection was 90.6, 100, 100 and 83.7%, respectively. We concluded that detection of pp65 antigen by FCA is more sensitive for diagnosis of HCMV infection than detection of HCMV-IgM antibody and is better than HCMV DNA quantification for distinguishing the symptomatic and asymptomatic HCMV infection in infants.
TL;DR: CLM represents a highly sensitive, fast, material-saving and non-toxic/non-radioactive method for the measurement of antigen-specific CTL cytotoxic activity.
Abstract: A coupled luminescent method (CLM) based on glyceraldehyde-3-phosphate dehydrogenase released from injured target cells was used to evaluate the cytotoxicity of antigen-specific HLA class I-restricted CTLs. In contrast to established methods, CLM does not require the pretreatment of target cells with radioactive or toxic labeling substances. CTLs from healthy HLA-A2 positive donors were stimulated by autologous dendritic cells (DCs) pulsed with HLA-A2 restricted HCMV-pp65 nonamer peptides. HLA-A2 positive T2 cells or autologous monocytes pulsed with HCMV-pp65 nonamer peptide served as target cells. Lysis was detected only in HCMV-pp65-pulsed target cells incubated with CTLs from seropositive donors stimulated by HCMV-pp65-pulsed DCs. After 3 days, stimulation 38% of T2 cells and 17% of monocytes were lysed at an effector to target ratio of 8:1. In conclusion, CLM represents a highly sensitive, fast, material-saving and non-toxic/non-radioactive method for the measurement of antigen-specific CTL cytotoxic activity.