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Showing papers on "Antibody published in 2004"


Journal ArticleDOI
TL;DR: The U.S. Food and Drug administration has approved several polyclonal antibody preparations and at least 18 monoclonal antibody preparations (antibodies, antibody fragments, antibody fusion proteins, etc.) which are associated with several interesting pharmacokinetic characteristics.

886 citations


Journal ArticleDOI
15 Mar 2004-Blood
TL;DR: The data suggest that MM "stem cells" are CD138- B cells with the ability to replicate and subsequently differentiate into malignant CD138+ plasma cells.

806 citations


Journal ArticleDOI
01 Dec 2004-Blood
TL;DR: It is proposed that these IgM(+)IgD(+)CD27(+) B cells provide the splenic marginal zone with a diversified and protective preimmune repertoire in charge of the responses against encapsulated bacteria.

776 citations


Journal ArticleDOI
TL;DR: The results show that it is possible to interrogate the memory repertoire of immune donors to rapidly and efficiently isolate neutralizing antibodies that have been selected in the course of natural infection.
Abstract: Passive serotherapy can confer immediate protection against microbial infection, but methods to rapidly generate human neutralizing monoclonal antibodies are not yet available. We have developed an improved method for Epstein-Barr virus transformation of human B cells. We used this method to analyze the memory repertoire of a patient who recovered from severe acute respiratory syndrome coronavirus (SARS-CoV) infection and to isolate monoclonal antibodies specific for different viral proteins, including 35 antibodies with in vitro neutralizing activity ranging from 10(-8)M to 10(-11)M. One such antibody confers protection in vivo in a mouse model of SARS-CoV infection. These results show that it is possible to interrogate the memory repertoire of immune donors to rapidly and efficiently isolate neutralizing antibodies that have been selected in the course of natural infection.

754 citations



Journal ArticleDOI
01 Apr 2004-Nature
TL;DR: Gene-based vaccination for the SARS-CoV elicits effective immune responses that generate protective immunity in an animal model, and induces T cell and neutralizing antibody responses, as well as protective immunity, in a mouse model.
Abstract: Public health measures have successfully identified and contained outbreaks of the severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV), but concerns remain over the possibility of future recurrences. Finding a vaccine for this virus therefore remains a high priority. Here, we show that a DNA vaccine encoding the spike (S) glycoprotein of the SARS-CoV induces T cell and neutralizing antibody responses, as well as protective immunity, in a mouse model. Alternative forms of S were analysed by DNA immunization. These expression vectors induced robust immune responses mediated by CD4 and CD8 cells, as well as significant antibody titres, measured by enzyme-linked immunosorbent assay. Moreover, antibody responses in mice vaccinated with an expression vector encoding a form of S that includes its transmembrane domain elicited neutralizing antibodies. Viral replication was reduced by more than six orders of magnitude in the lungs of mice vaccinated with these S plasmid DNA expression vectors, and protection was mediated by a humoral but not a T-cell-dependent immune mechanism. Gene-based vaccination for the SARS-CoV elicits effective immune responses that generate protective immunity in an animal model.

675 citations


Journal ArticleDOI
TL;DR: It is found that the innate monocyte network depletes B cells through FcγR-dependent pathways during anti-CD20 immunotherapy has important clinical implications for anti- CD20 and other antibody-based therapies.
Abstract: Anti-CD20 antibody immunotherapy effectively treats non-Hodgkin9s lymphoma and autoimmune disease. However, the cellular and molecular pathways for B cell depletion remain undefined because human mechanistic studies are limited. Proposed mechanisms include antibody-, effector cell–, and complement-dependent cytotoxicity, the disruption of CD20 signaling pathways, and the induction of apoptosis. To identify the mechanisms for B cell depletion in vivo, a new mouse model for anti-CD20 immunotherapy was developed using a panel of twelve mouse anti–mouse CD20 monoclonal antibodies representing all four immunoglobulin G isotypes. Anti-CD20 antibodies rapidly depleted the vast majority of circulating and tissue B cells in an isotype-restricted manner that was completely dependent on effector cell Fc receptor expression. B cell depletion used both FcγRI- and FcγRIII-dependent pathways, whereas B cells were not eliminated in FcR common γ chain–deficient mice. Monocytes were the dominant effector cells for B cell depletion, with no demonstrable role for T or natural killer cells. Although most anti-CD20 antibodies activated complement in vitro, B cell depletion was completely effective in mice with genetic deficiencies in C3, C4, or C1q complement components. That the innate monocyte network depletes B cells through FcγR-dependent pathways during anti-CD20 immunotherapy has important clinical implications for anti-CD20 and other antibody-based therapies.

668 citations


Journal ArticleDOI
15 Sep 2004-Blood
TL;DR: With increasing evidence that mAb therapeutic activity in vivo depends on complement activation, these new CD20 reagents with their slow off-rates and increased potency in CDC hold considerable promise for improved clinical activity.

637 citations


Journal ArticleDOI
TL;DR: Data suggest that the 80R human monoclonal antibody may be a useful viral entry inhibitor for the emergency prophylaxis and treatment of SARS, and that the ACE2-binding site of S1 could be an attractive target for subunit vaccine and drug development.
Abstract: Effective prophylaxis and antiviral therapies are urgently needed in the event of reemergence of the highly contagious and often fatal severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV) infection. We have identified eight recombinant human single-chain variable region fragments (scFvs) against the S1 domain of spike (S) protein of the SARS-CoV from two nonimmune human antibody libraries. One scFv 80R efficiently neutralized SARS-CoV and inhibited syncytia formation between cells expressing the S protein and those expressing the SARS-CoV receptor angiotensin-converting enzyme 2 (ACE2). Mapping of the 80R epitope showed it is located within the N-terminal 261–672 amino acids of S protein and is not glycosylation-dependent. 80R scFv competed with soluble ACE2 for association with the S1 domain and bound S1 with high affinity (equilibrium dissociation constant, Kd = 32.3 nM). A human IgG1 form of 80R bound S1 with a 20-fold higher affinity of 1.59 nM comparable to that of ACE2 (Kd = 1.70 nM), and neutralized virus 20-fold more efficiently than the 80R scFv. These data suggest that the 80R human monoclonal antibody may be a useful viral entry inhibitor for the emergency prophylaxis and treatment of SARS, and that the ACE2-binding site of S1 could be an attractive target for subunit vaccine and drug development.

590 citations


Journal ArticleDOI
TL;DR: Necrotic and late apoptotic cells release material that, combined with SLE IgG, induces production of IFN alpha in PDCs, and the presence of Sle IgG was necessary, and its activity correlated with the existence of antibodies to RNA-binding proteins, but not anti-DNA antibodies.
Abstract: Objective To investigate the release of interferon-α (IFNα)–inducing material by necrotic or apoptotic cells, its properties, and the necessity of autoantibodies from systemic lupus erythematosus (SLE) patients for the interferogenic activity. Methods U937 monocytic leukemia cells or peripheral blood mononuclear cells (PBMCs) were rendered necrotic by freeze-thawing or apoptotic by treatment with ultraviolet light. Cell culture supernatants from these cells and IgG from SLE patients (SLE IgG) were added to cultures of normal PBMCs or purified plasmacytoid dendritic cells (PDCs). The importance of nucleic acids for IFNα induction was investigated by RNase and DNase treatment. The IFNα levels were measured by immunoassay. Results Both necrotic and apoptotic U937 cells released material that, combined with SLE IgG, induced IFNα production in PDCs. The release from apoptotic cells occurred with a 16-hour delay, in late apoptosis. Also, normal PBMCs released IFNα-inducing material, but only during necrosis. The interferogenic activity of the necrotic material required the presence of RNA, while both RNA and DNA were important in the apoptotic material. In both cases, the presence of SLE IgG was necessary, and its activity correlated with the presence of antibodies to RNA-binding proteins, but not anti-DNA antibodies. Conclusion Necrotic and late apoptotic cells release material that, combined with SLE IgG, induces production of IFNα in PDCs. The IFNα inducers probably consist of immune complexes (ICs) containing RNA and possibly DNA as essential interferogenic components. The presence of such interferogenic ICs could explain the ongoing production of IFNα in SLE and could be of etiopathogenic importance.

536 citations


Journal ArticleDOI
TL;DR: Grass pollen immunotherapy may induce allergen-specific, IL-10-dependent “protective” IgG4 responses and both the increases in IgG and the IgG “blocking” activity correlated with the patients’ overall assessment of improvement.
Abstract: T regulatory cells and IL-10 have been implicated in the mechanism of immunotherapy in patients with systemic anaphylaxis following bee stings. We studied the role of IL-10 in the induction of clinical, cellular, and humoral tolerance during immunotherapy for local mucosal allergy in subjects with seasonal pollinosis. Local and systemic IL-10 responses and serum Ab concentrations were measured before/after a double-blind trial of grass pollen ( Phleum pratense , Phl P) immunotherapy. We observed local increases in IL-10 mRNA-positive cells in the nasal mucosa after 2 years of immunotherapy, but only during the pollen season. IL-10 protein-positive cells were also increased and correlated with IL-10 mRNA + cells. These changes were not observed in placebo-treated subjects or in healthy controls. Fifteen and 35% of IL-10 mRNA signals were colocalized to CD3 + T cells and CD68 + macrophages, respectively, whereas only 1–2% of total CD3 + cells and 4% of macrophages expressed IL-10. Following immunotherapy, peripheral T cells cultured in the presence of grass pollen extract also produced IL-10. Immunotherapy resulted in blunting of seasonal increases in serum allergen Phl p 5-specific IgE, 60- to 80-fold increases in Phl p 5-specific IgG, and 100-fold increases in Phl p 5-specific IgG4. Post-immunotherapy serum exhibited inhibitory activity, which coeluted with IgG4, and blocked IgE-facilitated binding of allergen-IgE complexes to B cells. Both the increases in IgG and the IgG “blocking” activity correlated with the patients’ overall assessment of improvement. Thus, grass pollen immunotherapy may induce allergen-specific, IL-10-dependent “protective” IgG4 responses.

Journal ArticleDOI
TL;DR: It is shown that murine DCs are much more effectively activated by immune complex that contain IgG bound to chromatin than by immune complexes that contain foreign protein.
Abstract: Dendritic cell (DC) activation by nucleic acid–containing immunoglobulin (Ig)G complexes has been implicated in systemic lupus erythematosus (SLE) pathogenesis. However, the mechanisms responsible for activation and subsequent disease induction are not completely understood. Here we show that murine DCs are much more effectively activated by immune complexes that contain IgG bound to chromatin than by immune complexes that contain foreign protein. Activation by these chromatin immune complexes occurs by two distinct pathways. One pathway involves dual engagement of the Fc receptor FcγRIII and Toll-like receptor (TLR)9, whereas the other is TLR9 independent. Furthermore, there is a characteristic cytokine profile elicited by the chromatin immune complexes that distinguishes this response from that of conventional TLR ligands, notably the induction of BAFF and the lack of induction of interleukin 12. The data establish a critical role for self-antigen in DC activation and explain how the innate immune system might drive the adaptive immune response in SLE.

Journal ArticleDOI
TL;DR: The findings reveal that the zebrafish immune system is morphologically and functionally mature by 4-6wpf, indicating that immunocompetence was achieved.
Abstract: The development and maturation of the immune system in zebrafish was investigated using immune-related gene expression profiling by quantitative real-time polymerase chain reaction, in situ hybridization (ISH), immunoglobulin (Ig) detection by immuno-affinity purification and Western blotting as well as immersion immunization experiments. Ikaros expression was first detected at 1 day post-fertilization (dpf) and thereafter increased gradually to more than two-fold between 28 and 42dpf before decreasing to less than the initial 1dpf expression level in adult fish (aged 105dpf). Recombination activating gene-1 (Rag-1) expression levels increased rapidly (by 10-fold) between 3 and 17dpf, reaching a maximum between 21 and 28dpf before decreasing gradually. However, in adult fish aged 105dpf, the expression level of Rag-1 had dropped markedly, and was equivalent to the expression level at 3dpf. T-cell receptor alpha constant region and immunoglobulin light chain constant region (IgLC) isotype-1, 2 and 3 mRNAs were detected at low levels by 3dpf and their expression levels increased steadily to the adult range between 4 and 6 weeks post-fertilization (wpf). Using tissue-section ISH, Rag-1 expression was detected in head kidney by 2wpf while IgLC-1, 2 and 3 were detected in the head kidney and the thymus by 3wpf onwards. Secreted Ig was only detectable using immuno-affinity purification and Western blotting by 4wpf. Humoral response to T-independent antigen (formalin-killed Aeromonas hydrophila) and T-dependent antigen (human gamma globulin) was observed in zebrafish immunized at 4 and 6wpf, respectively, indicating that immunocompetence was achieved. The findings reveal that the zebrafish immune system is morphologically and functionally mature by 4-6wpf.

Journal ArticleDOI
TL;DR: B‐1a and IgM memory B cells may function as a link between the innate and adaptive immune response and thus perform a primordial B‐cell function.
Abstract: In man and in mouse, B-cell maturation occurs in steps, first in the bone marrow from hematopoietic precursors to immature/transitional B cells, then in the periphery from transitional to fully mature B cells. Each developmental step is tightly controlled by the expression and function of the B-cell receptor (BCR) and by the ability to interact with the microenvironment. Mature B cells collaborate with T cells in the adaptive immune response, leading to the production of high-affinity antibodies. This response is very accurate, but slow. Immediately after pathogen entry, however, antibodies already present in the serum reinforce the innate immune response and contribute to the first-line defense against infection. Low-affinity natural antibodies are produced by B-1a B cells in the mouse and immunoglobulin M (IgM) memory cells in man. These antibodies represent an immediate protection against all microorganisms and the only one against encapsulated bacteria. B-1a and IgM memory B cells may function as a link between the innate and adaptive immune response and thus perform a primordial B-cell function.

Journal ArticleDOI
TL;DR: A pharmacokinetics study of two mutant IgG2 antibodies with increased FcRn binding affinity indicated that they had serum half-lives in rhesus monkeys ∼2-fold longer than the wild-type antibody.

Journal ArticleDOI
TL;DR: In an unplanned analysis, vaccinated patients appeared to have superior clinical outcomes to those treated with placebo or protein alone, suggesting the vaccine is safe and highly potent immunologically.
Abstract: NY-ESO-1 is a “cancer-testis” antigen expressed in many cancers. ISCOMATRIX is a saponin-based adjuvant that induces antibody and T cell responses. We performed a placebo-controlled clinical trial evaluating the safety and immunogenicity of recombinant NY-ESO-1 protein with ISCOMATRIX adjuvant. Forty-six evaluable patients with resected NY-ESO-1-positive tumors received three doses of vaccine intramuscularly at monthly intervals. The vaccine was well tolerated. We observed high-titer antibody responses, strong delayed-type hypersensitivity reactions, and circulating CD8+ and CD4+ T cells specific for a broad range of NY-ESO-1 epitopes, including known and previously unknown epitopes. In an unplanned analysis, vaccinated patients appeared to have superior clinical outcomes to those treated with placebo or protein alone. The vaccine is safe and highly potent immunologically.

Journal ArticleDOI
TL;DR: This assay is used to demonstrate that the anthrax vaccine (AVA; BioThrax) elicits a substantial population of protective-antigen (PA) specific memory B cells, and these B cells satisfy the canonical surface phenotype of humanMemory B cells.

Journal ArticleDOI
TL;DR: Five sets of patients with strikingly similar B cell antigen receptors arising from the use of common H and L chain V region gene segments are described, implying a much more striking degree of structural restriction of the entire BCR and a much higher frequency of receptor sharing among patients than appreciated previously.
Abstract: Previous studies suggest that the diversity of the expressed variable (V) region repertoire of the immunoglobulin (Ig)H chain of B-CLL cells is restricted. Although limited examples of marked constraint in the primary structure of the H and L chain V regions exist, the possibility that this level of restriction is a general principle in this disease has not been accepted. This report describes five sets of patients, mostly with unmutated or minimally mutated IgV genes, with strikingly similar B cell antigen receptors (BCRs) arising from the use of common H and L chain V region gene segments that share CDR3 structural features such as length, amino acid composition, and unique amino acid residues at recombination junctions. Thus, a much more striking degree of structural restriction of the entire BCR and a much higher frequency of receptor sharing exists among patients than appreciated previously. The data imply that either a significant fraction of B-CLL cells was selected by a limited set of antigenic epitopes at some point in their development and/or that they derive from a distinct B cell subpopulation with limited Ig V region diversity. These shared, stereotyped Ig molecules may be valuable probes for antigen identification and important targets for cross-reactive idiotypic therapy.

Journal ArticleDOI
TL;DR: Infection with a parasite that induces a “Th2-type response” resulted in accumulation of tissue basophils, and these cells, stimulated by a non-FcR cross-linking mechanism, are a principal source of in vivo IL-4 production.
Abstract: Using mice in which the eGfp gene replaced the first exon of the Il4 gene (G4 mice), we examined production of interleukin (IL)-4 during infection by the intestinal nematode Nippostrongylus brasiliensis (Nb). Nb infection induced green fluorescent protein (GFP)pos cells that were FcepsilonRIpos, CD49bbright, c-kitneg, and Gr1neg. These cells had lobulated nuclei and granules characteristic of basophils. They were found mainly in the liver and lung, to a lesser degree in the spleen, but not in the lymph nodes. Although some liver basophils from naive mice express GFP, Nb infection enhanced GFP expression and increased the number of tissue basophils. Similar basophil GFP expression was found in infected Stat6-/- mice. Basophils did not increase in number in infected Rag2-/- mice; Rag2-/- mice reconstituted with CD4 T cells allowed significant basophil accumulation, indicating that CD4 T cells can direct both tissue migration of basophils and enhanced IL-4 production. IL-4 production was immunoglobulin independent and only partially dependent on IL-3. Thus, infection with a parasite that induces a "Th2-type response" resulted in accumulation of tissue basophils, and these cells, stimulated by a non-FcR cross-linking mechanism, are a principal source of in vivo IL-4 production.

Journal ArticleDOI
TL;DR: Intranasal or intramuscular inoculations of BALB/c mice with MVA/S produced serum antibodies that recognized the SARS S in ELISA and neutralized SARS-CoV in vitro, demonstrating a role for antibody to S in protection.
Abstract: The spike protein (S), a membrane component of severe acute respiratory syndrome coronavirus (SARS-CoV) is anticipated to be an important component of candidate vaccines. We constructed recombinant forms of the highly attenuated modified vaccinia virus Ankara (MVA) containing the gene encoding full-length SARS-CoV S with and without a C-terminal epitope tag called MVA/S-HA and MVA/S, respectively. Cells infected with MVA/Sor MVA/S-HA synthesized a 200-kDa protein, which was recognized by antibody raised against a synthetic peptide of SARS-CoV S or the epitope tag in Western blot analyses. Further studies indicated that S was N-glycosylated and migrated in SDS polyacrylamide gels with an apparent mass of ≈160 kDa after treatment with peptide N-glycosidase F. The acquisition of resistance to endoglycosidase H indicated trafficking of S to the medial Golgi compartment, and confocal microscopy showed that S was transported to the cell surface. Intranasal or intramuscular inoculations of BALB/c mice with MVA/S produced serum antibodies that recognized the SARS S in ELISA and neutralized SARS-CoV in vitro. Moreover, MVA/S administered by either route elicited protective immunity, as shown by reduced titers of SARS-CoV in the upper and lower respiratory tracts of mice after challenge. Passive transfer of serum from mice immunized with MVA/S to naive mice also reduced the replication of SARS-CoV in the respiratory tract after challenge, demonstrating a role for antibody to S in protection. The attenuated nature of MVA and the ability of MVA/S to induce neutralizing antibody that protects mice support further development of this candidate vaccine.

Journal ArticleDOI
TL;DR: Though antiproliferative immunosuppressive therapy depleted short-lived plasmablasts, long-lived plasma cells survived and continued to produce (auto)antibodies.
Abstract: The current view holds that chronic autoimmune diseases are driven by the continuous activation of autoreactive B and T lymphocytes. However, despite the use of potent immunosuppressive drugs designed to interfere with this activation the production of autoantibodies often persists and contributes to progression of the immunopathology. In the present study, we analyzed the life span of (auto)antibody-secreting cells in the spleens of NZB × NZW F1 (NZB/W) mice, a murine model of systemic lupus erythematosus. The number of splenic ASCs increased in mice aged 1–5 mo and became stable thereafter. Less than 60% of the splenic (auto)antibody-secreting cells were short-lived plasmablasts, whereas 40% were nondividing, long-lived plasma cells with a half-life of >6 mo. In NZB/W mice and D42 Ig heavy chain knock-in mice, a fraction of DNA-specific plasma cells were also long-lived. Although antiproliferative immunosuppressive therapy depleted short-lived plasmablasts, long-lived plasma cells survived and continued to produce (auto)antibodies. Thus, long-lived, autoreactive plasma cells are a relevant target for researchers aiming to develop curative therapies for autoimmune diseases.

Journal ArticleDOI
TL;DR: The structural information that is emerging on three human immunoglobulin classes and their FcRs is reviewed, including an understanding of the antibody conformational adjustments that are required to bring effector cell and target cell membranes sufficiently close for efficient killing and signal transduction to occur.
Abstract: Immunoglobulins couple the recognition of invading pathogens with the triggering of potent effector mechanisms for pathogen elimination. Different immunoglobulin classes trigger different effector mechanisms through interaction of immunoglobulin Fc regions with specific Fc receptors (FcRs) on immune cells. Here, we review the structural information that is emerging on three human immunoglobulin classes and their FcRs. New insights are provided, including an understanding of the antibody conformational adjustments that are required to bring effector cell and target cell membranes sufficiently close for efficient killing and signal transduction to occur. The results might also open up new possibilities for the design of therapeutic antibodies.

Journal ArticleDOI
TL;DR: In this article, passive transfer of immune serum to naive mice prevented virus replication in the lower respiratory tract following intranasal challenge, which is a promising observation for the development of vaccines, immunotherapy, and immunoprophylaxis regimens.
Abstract: Following intranasal administration, the severe acute respiratory syndrome (SARS) coronavirus replicated to high titers in the respiratory tracts of BALB/c mice. Peak replication was seen in the absence of disease on day 1 or 2, depending on the dose administered, and the virus was cleared within a week. Viral antigen and nucleic acid were detected in bronchiolar epithelial cells during peak viral replication. Mice developed a neutralizing antibody response and were protected from reinfection 28 days following primary infection. Passive transfer of immune serum to naive mice prevented virus replication in the lower respiratory tract following intranasal challenge. Thus, antibodies, acting alone, can prevent replication of the SARS coronavirus in the lung, a promising observation for the development of vaccines, immunotherapy, and immunoprophylaxis regimens.

Patent
09 Jul 2004
TL;DR: An antibody binding to IGF-IR and inhibiting the binding of IGF-I and IGF-II to IG-RI which is characterized in that said antibody is of human IgG1 isotype, and shows a ratio of inhibition of the binding binding of I and II to I and I, respectively, of 1:3 to 3:1, and induces celle death of 20% or more cells of a preparation of IG-IR expressing cells after 24 hours at a concentration of said antibody of 100 nM by ADCC; has improved properties in antitumor therapy as mentioned in this paper
Abstract: An antibody binding to IGF-IR and inhibiting the binding of IGF-I and IGF-II to IG-RI which is characterized in that said antibody is of human IgG1 isotype, and shows a ratio of inhibition of the binding of IGF-I to IGF-IR to the inhibition of binding of IGF-II to IGF-IR of 1:3 to 3:1, and induces celle death of 20% or more cells of a preparation of IGF-IR expressing cells after 24 hours at a concentration of said antibody of 100 nM by ADCC; has improved properties in antitumor therapy.

Journal ArticleDOI
TL;DR: These experiments suggest that, while specific antibody is responsible for terminating viremia, CD8+ T cells have an important function in clearing infection from tissues and preventing viral persistence.
Abstract: Infection with West Nile virus (WNV) causes fatal encephalitis more frequently in immunocompromised humans than in those with a healthy immune system. Although a complete understanding of this increased risk remains unclear, experiments with mice have begun to define how different components of the adaptive and innate immune response function to limit infection. Previously, we demonstrated that components of humoral immunity, particularly immunoglobulin M (IgM) and IgG, have critical roles in preventing dissemination of WNV infection to the central nervous system. In this study, we addressed the function of CD8 + T cells in controlling WNV infection. Mice that lacked CD8 + T cells or classical class Ia major histocompatibility complex (MHC) antigens had higher central nervous system viral burdens and increased mortality rates after infection with a low-passage-number WNV isolate. In contrast, an absence of CD8 + T cells had no effect on the qualitative or quantitative antibody response and did not alter the kinetics or magnitude of viremia. In the subset of CD8 + -T-cell-deficient mice that survived initial WNV challenge, infectious virus was recovered from central nervous system compartments for several weeks. Primary or memory CD8 + T cells that were generated in vivo efficiently killed target cells that displayed WNV antigens in a class I MHC-restricted manner. Collectively, our experiments suggest that, while specific antibody is responsible for terminating viremia, CD8 + T cells have an important function in clearing infection from tissues and preventing viral persistence.

Journal ArticleDOI
TL;DR: Results identify S among the structural proteins as the only significant SARS-CoV neutralization antigen and protective antigen and show that a single mucosal immunization is highly protective in an experimental animal that supports efficient replication of SARS -CoV.
Abstract: We investigated the contributions of the structural proteins of severe acute respiratory syndrome (SARS) coronavirus (CoV) to protective immunity by expressing them individually and in combinations from a recombinant parainfluenza virus (PIV) type 3 vector called BHPIV3. This vector provided direct immunization of the respiratory tract, the major site of SARS transmission, replication, and disease. The BHPIV3/SARS recombinants were evaluated for immunogenicity and protective efficacy in hamsters, which support a high level of pulmonary SARS-CoV replication. A single intranasal administration of BHPIV3 expressing the SARS-CoV spike protein (S) induced a high titer of SARS-CoV-neutralizing serum antibodies, only 2-fold less than that induced by SARS-CoV infection. The expression of S with the two other putative virion envelope proteins, the matrix M and small envelope E proteins, did not augment the neutralizing antibody response. In absence of S, expression of M and E or the nucleocapsid protein N did not induce a detectable serum SARS-CoV-neutralizing antibody response. Immunization with BHPIV3 expressing S provided complete protection against SARS-CoV challenge in the lower respiratory tract and partial protection in the upper respiratory tract. This was augmented slightly by coexpression with M and E. Expression of M, E, or N in the absence of S did not confer detectable protection. These results identify S among the structural proteins as the only significant SARS-CoV neutralization antigen and protective antigen and show that a single mucosal immunization is highly protective in an experimental animal that supports efficient replication of SARS-CoV.

Journal ArticleDOI
TL;DR: It is shown that a recombinant fusion protein (designated RBD-Fc) containing 193-amino acid RBD and a human IgG1 Fc fragment can inducehighly potent antibody responses in the immunized rabbits and suggests that RBD can induce highly potent neutralizing antibody responses and has potential to be developed as an effective and safe subunit vaccine for prevention of SARS.

Journal ArticleDOI
TL;DR: The biochemical mechanism and regulation of SHM and CSR are the topic of this review and are largely targeted to the Ig genes, but their targeting to other genes causes many of the B-cell lymphomas in mice and humans.
Abstract: Antibody-mediated immunity is critical to the resistance of vertebrate species to pathogenic organisms. Although low-affinity immunoglobin (Ig) M antibodies circulate in the blood prior to encountering pathogens, high-affinity IgG and IgA antibodies are required to inactivate toxins, neutralize viruses, and promote the clearance of microorganisms. Individuals, such as those with hyper-IgM syndrome (HIGM), who lack the ability to make such high-affinity IgG and IgA antibodies, are unable to combat bacterial and viral infections and usually die at a young age (Revy et al. 2000; Imai et al. 2003). Prior to exposure to antigen, the initial generation of a diverse antibody repertoire is achieved early in B-lymphocyte development by the successful rearrangement of the V, D, and J gene segments to produce B cells, each of which makes a unique Ig heavyand light-chain variable (V) region (Fig. 1A; Tonegawa 1983). These V regions encode the antigen binding sites of antibodies that are then expressed on the surface of a B lymphocyte and its clonal progeny. Following specific antigen recognition by its cognate B lymphocyte and costimulation by helper T lymphocytes, the B lymphocyte enters the germinal center of peripheral lymphoid organs to become a centroblast B cell. There, a second wave of antibody diversification occurs through somatic hypermutation (SHM) and/or gene conversion (GC) of the V region to generate high-affinity antigen binding sites (Fig. 1B; MacLennan 1994). SHM is the predominant mechanism in mice and humans, whereas GC occurs in chickens and some other species (Weill and Reynaud 1996). In the same centroblast B cell, the heavy-chain V regions encoding the antigen binding sites are rearranged down the chromosome through class switch recombination (CSR) so that they can be expressed with one of the constant (C) region genes to carry out many different effector functions and be distributed throughout the body (Fig. 1B; Manis et al. 2002b). SHM and CSR are largely targeted to the Ig genes, but their targeting to other genes causes many of the B-cell lymphomas in mice and humans (Pasqualucci et al. 2001). The biochemical mechanism and regulation of SHM and CSR are the topic of this review.

Journal ArticleDOI
TL;DR: The development and use of radionuclide-bearing monoclonal antibody therapies are discussed, with a focus on radiolabelled monOClonal antibodies that have been evaluated in clinical trials.
Abstract: Several monoclonal antibodies are now approved for cancer therapy, such as rituximab, an anti-CD20 monoclonal antibody for the treatment of B-cell non-Hodgkin's lymphoma Such 'naked' antibodies can recruit the body's immune effector mechanisms to kill cells expressing the target of the antibody In recent years, the linking of radionuclides to antibodies to either augment inherent activity or to exploit the specific targeting properties of monoclonal antibodies has been a major area of development Two radionuclide-bearing monoclonal antibody therapies have recently been approved by the US FDA, and several more are in clinical trials Here, we discuss the development and use of radiolabelled monoclonal antibody therapies, with a focus on radiolabelled monoclonal antibodies that have been evaluated in clinical trials

Journal ArticleDOI
Bao-Mei Shao1, Wen Xu1, Hui Dai1, Peng-Fei Tu1, Zhongjun Li1, Xiaoming Gao1 
TL;DR: It is demonstrated that Astragalus polysaccharide fractions activates mouse B cells and macrophages, but not T cells, in terms of proliferation or cytokine production, indicating that APS activates B cells via membrane Ig in a TLR4-independent manner.