Showing papers on "Virus published in 1976"

Germ line integration and Mendelian transmission of the exogenous Moloney leukemia virus.

Abstract: Mice were infected with the exogenous Moloney leukemia virus (M-MuLV) at two different stages of development. Either newborn mice (which can be considered as essentially fully differentiated animals) or preimplantation mouse embryos (at the 4-8 cell stage) were infected with M-MuLV. In both cases, animals that had developed an M-MuLV-induced leukemia were obtained. Two lines of evidence indicate that infection of preimplantation embryos, in contrast to infection of newborns, can lead to integration of the virus into the germ line. 1. Viremic males of the first backcross generation (N-1 generation) transmitted the virus to 50% of their offspring (N-2 generation) when mated with uninfected females. Likewise, a 50% transmission was observed from viremic N-2 and N-3 males to the next generations. 2. Molecular hybridization experiments revealed that viremic N-1 and N-2 animals carried one copy of M-MuLV per diploid mouse genome equivalent in all "non-target" organs tested. Together, both experiments indicate that the exogenous M-MuLV can be converted to an endogenous virus after infection of preimplantation embryos. The available evidence suggests that M-MuLV integrated into the germ line at one out of two possible integration sites. Thus, viremic backcross animals are heterozygous for a single Mendelian locus carrying the M-MuLV gene. During leukemogenesis an amplification of the M-MuLV from one copy to a maximum of four copies per diploid mouse genome equivalent takes place in the tumor tissues.

Transformation by murine and feline sarcoma viruses specifically blocks binding of epidermal growth factor to cells.

Abstract: Normal cells in culture have membrane receptors for epidermal growth factor (EGF); EGF stimulates cells to divide by binding to these receptors. Cells transformed by murine and feline sarcoma viruses rapidly lose the ability to bind EGF, whereas cells transformed by the DNA tumour viruses, polyoma and SV40, or infected with non-transforming RNA tumour viruses have normal levels of functional EGF receptors. The results suggest that a produce of the sarcoma virus genome specifically changes cell EGF receptors; the sarcoma gene product may, then, be functionally related to EGF.

Specificity of Virus‐Immune Effector T Cells for H‐2K or H‐2D Compatible Interactions: Implications for H‐Antigen Diversity

Abstract: Our interest in immunogenetics started with the quite fortuitous finding that cytotoxic thymus-derived lymphocytes (T cells) from mice infected acutely with lymphocytic choriomeningitis virus (LCMV) interact only with H-2 compatible virus-infected target cells (Doherty & Zinkemagel 1974, Zinkemagel & Doherty 1974b). The idea underlying our original experiment was that, because acute LCM is apparently a T cell-mediated immunopathol ogical process, variations in susceptibility to LCM disease may be due to genetically determined differences in T cell responsiveness (Tosolini & Mims 1971, Doherty & Zinkemagel 1974, McDevitt et al. 1974). We found, however, that there was an all-or-none effect: virus-infected L-929 fibroblasts (L cells, H-2'') were lysed only by H-Z\" compatible virusimmune T cells. The significance of this result was immediately recognized, not least because the paper of Katz et al. (1973) on H-2 restriction of T cell helper activity had recently appeared. The immediate reaction was

Inhibition of Influenza Virus Replication in Tissue Culture by 2-deoxy-2,3-dehydro-N-trifluoroacetylneuraminic acid (FANA): Mechanism of Action

Abstract: The neuraminidase inhibitor 2-deoxy-2,3-dehydro-N-trifluoroacetylneuraminic acid (FANA) inhibits the mutlicycle replication of influenza viruses in tissue culture. Influenza virus grown in the presence of FANA contains neuraminic acid on its envelope which then serves as receptor for other virus particles causing extensive aggregation. Thus, FANA inhibits influenza virus replication by preventing the enzymatic removal of neuraminic acid from the virus envelope.

Naturally occurring murine leukemia viruses in wild mice: characterization of a new "amphotropic" class.

Abstract: A new class of murine leukemia viruses, isolated from wild Mus musculus trapped in California, is described. These viruses, designated "amphotropic," replicate in mouse, rabbit, mink, human, guinea pig, and rat cells, but not in hamster, quail, or duck cells. They show N-tropism for mouse cells, and do not trigger the XC cell response. They are distinct by interference and virus neutralization testing from the previously recognized mouse-tropic and xenotropic MuLV classes. Mouse-tropic viruses occuring along with three of the four amphotropic isolates were found to be distinguishable by virus neutralization from other mouse-tropic murine leukemia virus strains of laboratory mouse origin.

Respiratory syncytial virus infections within families.

Abstract: To examine intrafamily spread of respiratory syncytial virus infections and their associated illnesses, 36 families with 188 members were studied during an outbreak of such infections. Nurses visited every three to four days to obtain specimens for viral isolation and interview household members. The virus infected 44.4 per cent of families, and 21.9 per cent of all members. All age groups had appreciable attack rates (with a range of 16.8 per cent in adults to 29.4 per cent in infants). In infected families, 45.9 per cent of members became infected, including 10 of 16 infants. Secondary attack rate for all ages was 27 per cent, and that for infants 45.4 per cent. An infant's older sibling appeared most likely to introduce the virus into the family. Associated acute respiratory illnesses occurred in 94.9 per cent of cases, and appeared more severe than those not associated with respiratory syncytial virus. When the virus was introduced into a family the high attack rate produced an illness of age-related severity.

An improved technique for obtaining enhanced infectivity with herpes simplex virus type 1 DNA.

Abstract: Summary Cells infected with herpes simplex virus type 1 (HSV-1) DNA by the calcium phosphate precipitation technique produce virus which leads to the formation of plaques (Graham, Veldhuisen & Wilkie, 1973). In the study reported here we show that treatment of cell monolayers with dimethyl sulphoxide (DMSO) solutions after infection with DNA-calcium phosphate complexes leads to a considerable increase in the number of plaques obtained. The conditions for this enhancement of infectivity have been optimized for baby hamster kidney (BHK) cells, and increases in plaque numbers of over 100-fold have been obtained. The treatment appears to increase the proportion of cells which respond to DNA infection by initiating plaque formation, and results in a large increase in the measured specific infectivity of HSV-1 DNA. DMSO causes similar (but quantitatively different) responses in various other cell lines infected with HSV-1 DNA. BHK cells infected with either virus particles, or virus DNA by the DEAE-dextran technique (Laithier & Sheldrick, 1975), do not exhibit this massive enhancement following exposure to DMSO.

Role of interferon in the pathogenesis of virus diseases in mice as demonstrated by the use of anti-interferon serum. I. Rapid evolution of encephalomyocarditis virus infection.

Abstract: The role of interferon in the pathogenesis of encephalomyocarditis (EMC) virus infection was determined by treating mice with potent, partially purified sheep anti-mouse interferon globulin. In control mice, EMC virus was present in low titers in various visceral organs but attained high titers in the brain towards the 4th to 5th day, at which time mice died with signs of central nervous system disease. In mice treated with anti-mouse interferon globulin, virus was present in high titer in visceral organs 24--36 h after viral inoculation and virtually all mice were dead by 45 h. This rapid evolution of EMC virus infection was not observed in mice treated with the globulin fraction prepared from a normal sheep, from a sheep exhibiting a low anti-mouse interferon-neutralizing titer, nor from a sheep having a high titer of antibody to human leukocyte interferon. The experimental results indicated that anti-interferon globulin neutralized the interferon liberated by virus-infected cells, thus permitting extensive virus multiplication in several visceral organs. We conclude that interferon is an important early component of host resistance to this virus infection.

Biology of Feline Leukemia Virus in the Natural Environment

Abstract: The feline leukemia virus (FeLV) was discovered in 1964 in a cluster of cats with lymphosarcoma The observed clustering of cases of feline lymphosarcoma suggested that FeLV was an infectious agent for cats The development of a simple immunofluorescent test for FeLV permitted a seroepidemiological study to be undertaken on the distribution of the virus in cats living in their natural environment Over 2000 cats were tested, and the results showed conclusively that FeLV is an infectious agent for cats This finding has now been independently confirmed using three different test procedures After the infectious nature of FeLV was discovered, a simple FeLV test and removal program was devised to control the spread of the virus in the natural environment The spread of FeLV was controlled in 45 households by removing the FeLV-infected cats, while in 25 households, where the infected cats were left in contact with the uninfected cats, 12% of the uninfected cats became infected The ultimate control of FeLV awaits the development of an effective FeLV vaccine, which now seems feasible since we have already experimentally immunized some cats with attenuated FeLV Although FeLV is infectious for cats there is no evidence that FeLV can infect humans

Breast-feeding protects against respiratory syncytial virus infections.

Abstract: Eight out of 115 infants admitted to hospital with respiratory syncytial (RS) virus infection had been breast-fed compared with 46 out of 167 controls; this difference was statistically significant. Twenty-one specimens of human colostrum were examined, and all contained RS virus neutralising activity. Specific IgA and IgG were detected in 18 specimens, whereas IgM was detected in none. The titre of IgA antibody was usually higher and correlated more closely to the titre of neutralising activity than that of IgG. Infants inhale milk feeds and regurgitate them through the nose, and the IgA collecting in the respiratory tract might protect against severe respiratory infection. Alternatively, if severe RS virus illness is a sign of hypersensitivity to the virus breast-feeding might protect the infant from an early sensitising infection.

Suppression of glycoprotein formation of Semliki Forest, influenza, and avian sarcoma virus by tunicamycin.

Abstract: Tunicamycin, a new antibiotic, halts the formation of physical particles of Semliki forest and fowl plague virus, whereas avian oncornavirus particles which show a reduction in infectivity and do not contain detectable labeled glycoprotein are released in the presence of the drug. In Semliki forest virus-infected cells only the protein moieties of the glycoproteins could be labeled. In cells infected with fowl plague and avian sarcoma virus neither intact glycoproteins nor their protein moieties could be detected. By using a protease inhibitor (N-alpha-p-tosyl-L-lysin chloromethyl ketone, TLCK) it could be shown, however, that the carbohydrate-free hemagglutinin precursor of influenza virus is synthesized but is presumably degraded by intracellular proteases in the absence of TLCK as a consequence of the lack of carbohydrate.

Role of interferon in the pathogenesis of virus diseases in mice as demonstrated by the use of anti-interferon serum. II. Studies with herpes simplex, Moloney sarcoma, vesicular stomatitis, Newcastle disease, and influenza viruses.

Abstract: The effect of potent sheep anti-mouse interferon globulin was investigated in several different experimental virus diseases of mice In anti-interferon globulin-treated mice infected intraperitoneally with herpes simplex virus (HSV) type I, the latent period was shortened, and the overall LD50 was increased several hundredfold compared to virus-infected control mice When HSV was inoculated subcutaneously all anti-interferon globulin-treated mice died, whereas only 5% of virus-infected control mice died Subsequent treatment with anti-interferon globulin of previously HSV-infected mice did not result in reactivation of HSV Treatment of adult mice with anti-interferon globulin resulted in an earlier appearance of MSV-induced tumors, a greater number of mice bearing tumors, an increase in tumor size, and an increase in the duration of tumors All tumors eventually regressed despite reinjection of anti-interferon globulin Anti-interferon globulin treatment resulted in a rapid onset of disease and death in adult mice inoculated (intranasal) with VSV and in newborn mice infected with NDV Anti-interferon globulin exerted no effect on the course of influenza virus infection of mice We conclude that the early production of interferon is an importane element in the response of the mouse to several viruses exhibiting different pathogeneses

Serum dilution neutralization test for California group virus identification and serology.

Abstract: The serum dilution neutralization test was evaluated for serological diagnosis of California group arbovirus infections and identification of virus isolates. The technical advantages and the degree of subtype specificity of the serum dilution neutralization test over the hemagglutination inhibition test and the complement fixation test were demonstrated with paired specimens from human cases, single human survey sera, and sentinel rabbit sera. Twenty-one virus isolates from various geographical areas of the United States were also used to evaluate the efficacy of the serum dilution neutralization test for specific virus identification.

Theiler's Virus-Induced Demyelination: Prevention by Immunosuppression

Abstract: The effect of immunosuppression with cyclophosphamide and rabbit antiserum to mouse thymocytes on demyelination induced by Theiler's virus in SJL/J mice was ascertained from Epon-embedded sections (1 micrometer) of the central nervous system. Immunosuppression not only eliminated mononuclear cell infiltrates in the spinal cord white matter, but it also prevented the occurrence of demyelination. These results suggest that demyelination in this infection is immune-mediated.

Morphological and antigenic relationships between viruses (rotaviruses) from acute gastroenteritis of children, calves, piglets, mice, and foals.

Abstract: The reovirus-like particles present in the feces of young pigs and foals with acute enteritis and the virus causing epizootic diarrhea of infant mice were found to be indistinguishable morphologically from each other, from the South African SA. 11 and "O" viruses, and from the rotaviruses of children and calves. The inner capsid layer of each of these viruses reacted seriologically with sera of children, calves, mice, piglets, and foals convalescent from infection with their respective rotaviruses. These sera reacted by immunofluorescence with human, bovine, porcine, and murine rotaviruses, SA.11, and "O" viruses in tissue cultures and with human bovine, procine, nad murine viral antigens by complement fixation and gel diffusion. However, the antisera differed in their ability to react serologically with the outer capsid layer of the viruses investigated and in their ability to neutralize tissue culture-adapted calf virus. These two tests may demonstrate strain or host specificity among rotaviruses. Since the porcine, murine, and equine viruses are closely related serologically to and are morphologically identical to the human and bovine viruses, they should be included in the group of viruses for which the term "rotavirus" has been suggested. All known members of this proposed group of viruses share a common antigen, probably situated within the inner capsid layer; thus, any one of the viruses may be used for the preparation of antigen or antibody for diagnostic tests, and this will aid in the diagnosis of virus infection in those species from which a rotavirus has not been cultured.

Differences in RNA patterns of influenza A viruses.

Abstract: Analysis of the segmented RNAs of influenza A viruses by electrophoresis on polyacrylamide urea slab gels has provided a method for sharper resolution of the number and migration rates of different segments than previously has been possible. Using this system, the RNA genome of influenza A/WSN (HON1) virus can be separated into seven to nine separate bands, depending on whether virus is obtained after high or low multiplicity of infection, and the genome of influenza A/PR/8 (HON1) virus can be resolved into eight bands, six of which migrate differently from comparable RNA bands of WSN virus. Comparision of the RNA patterns produced by influenza A/PR/8 (HON1) and A/England/42/72 (H8n2) virus also reveals major differences in migration speeds of different bands, and analysis of the RNAs of the RNAs of an HON2 recombinant virus derived from these two strains permits the identification of RNA segments which have been derived from one particular parent. By extension of these techniques, it may be possible to define which RNA segment codes for each viral protein and to analyze recombinant strains to identify which genes have been derived from each of its parents.

Autoregulation of simian virus 40 gene A by T antigen.

Abstract: During lytic infection by simian virus 40, gene A is transcribed into early RNA, which is translated into A protein (T antigen). Both the rate of synthesis and the intracellular amount of early RNA are higher in cells infected by temperature-sensitive A (tsA) mutants than in cells infected by wild-type virus. These differences are observed at permissive temperature (32 degrees) and are amplified greatly after a shift to restrictive temperature (41 degrees). For example, at 32 degrees cells infected by tsA mutants synthesize early RNA approximately twice as fast as cells infected by wild-type virus. After the shift to 41 degrees, the rate of synthesis in the tsA infection increases to 15 times the rate in the wild-type infection. In contrast, cells infected by tsA mutants do not overproduce late RNA. We suggest that the A protein regulates its own synthesis by negative feedback control of gene A transcription.

Rhinovirus and influenza type A infections as precipitants of asthma.

Abstract: Specimens from 49 persons, 3 to 60 years of age, who were prone to attacks of apparently infectious asthma were cultured for viruses and bacteria during episodes of symptomatic respiratory infection from September 1972 to June 1973. Seventy-one of 128 episodes (55 per cent) of symptomatic respiratory infection occurred with asthma. Shedding of respiratory pathogens was associated with 43 of the 128 episodes, and 19 of the 43 etiologically defined episodes occurred with wheezing. Seven of 15 rhinovirus symptomatic respiratory infections were linked with asthma, as were 4 of 5 influenza type A (H3N2) and 2 of 3 respiratory syncytial virus infections. A total of 21 different rhinovirus serotypes have been identified from asthmatic patients during 2 years of study; 14 of these were associated with wheezing, indicating that the ability to cause asthma is not restricted to only a few types. Other viruses that were shed during wheezing-associated symptomatic respiratory infections included para-influenza type 3, adenovirus type 7, and 2 unidentified viruses. Although infectious asthma was not easily defined in adults and some older children, viruses that appeared to precipitate asthma were distributed among patients of widely differing ages.

Amphotropic host range of naturally occuring wild mouse leukemia viruses.

Abstract: Seven murine leukemia virus field isolates (uncloned) from wild mice (Musmusculus) of four widely separated areas in southern California show an unusually wide in vitro host range They replicate well in human, feline, canine, guinea pig, rabbit, rat, and mouse cells, whereas bovine, hamster, and avian cells are resistant Since this host range includes that of both mouse tropic (ecotropic) and xenotropic murine leukemia viruses, they are designated as "amphotropic" No purely xenotropic virus component is detectable in these field isolates They may represent the "wild" or ancestral viruses from which the ecotropic and xenotrophic murine leukemia virus strains of laboratory mice have been derived

The use of chicken tracheal organ cultures for the isolation and assay of avian infectious bronchitis virus.

Abstract: A study has been made of the use of chicken tracheal organ cultures for the isolation and assay of avian infectious bronchitis (AIB) virus from both naturally and experimentally infected chickens. Six strains of AIB virus were investigated, 3 of which had been isolated from natural outbreaks of disease. Two of the virus isolations from the outbreaks of AIB were made directly into tracheal organ cultures without passage in embryonated eggs.

Influenza virus genome consists of eight distinct RNA species

Abstract: The genomic RNA of the avian influenza A virus, fowl plague, was fractionated into eight species by electrophoresis in polyacrylamide-agarose gels containing 6 M urea. The separated 32P-labeled RNA species were characterized by digestion with RNase T1 and fractionation of the resulting oligonucleotides by two-dimensional gel electrophoresis; this demonstrated that each species has a distinct nucleotide sequence. A tentative correlation of each genome RNA species with the virus protein that it encodes was made.

Unrelated animal viruses share receptors.

Abstract: THE specific receptors for several non-enveloped viruses are present on cells in only limited numbers (1 × 104–10 × 104), and can therefore be saturated with excess virus1–5. An excess of inactivated poliovirus type 1 inhibits the attachment of infectious poliovirus of all 3 serotypes, but not the attachment of other viruses, including B Coxsackie viruses6. Most of the B Coxsackie viruses probably share the same receptor7, but Coxsackie viruses B1 and B3 do not compete for the poliovirus receptor1. Adenovirus 2 and 5 also appear to share the same receptor, since their attachment to host cells is blocked by an excess of the adenovirus type 2 fibre protein, which seems to be the receptor-recognising portion of the virus particle2. A number of other adenoviruses may also belong to the same receptor family since soluble antigens block their attachment to erythrocytes8. We here report results which permit the construction of a ‘receptor map’ for a number of non-enveloped viruses.

Infectious mononucleosis. Epstein-Barr-virus shedding in saliva and the oropharynx.

Abstract: In an examination of excretion patterns of Epstein-Barr virus in 104 throat washings from 20 patients with infectious mononucleosis we found that three persons regularly shed virus from the second week through the third month after onset; 15 demonstrated intermittent excretion over three months, and in two cases, no virus was detected. In oral secretions, the virus appeared to be located extracellularly. Transforming activity was demonstrated in aliquots after centrifugation and filtration, in a sample in which cells were disrupted before filtration, and in specimens after two years' storage. Multiple oropharyngeal sites were examined for presence of the virus. In one patient, virus was regularly demonstrated in throat washings and saliva; swabs from Stensen's duct orifices yielded virus in three of four cases. Demonstration of virus in these oropharyngeal specimens explains increased transmissibility in age groups in which salivary exchange is high.

H-2 Compatibility Requirement for Virus-Specific T Cell-Mediated Effector Functions in Vivo: I. Specificity of T Cells Conferring Antiviral Protection Against Lymphocytic Choriomeningitis Virus Is Associated with H-2K and H-2D

Abstract: Adoptive immunization of recipient mice preinfected with lymphocytic choriomeningitis virus (LCMV) is mediated exclusively by virus-specific thymus-derived lymphocytes, when assayed in a short-term transfer model. Protection, measured as reduction of LCMV plaque-forming units in spleens, is conferred only if donors of immune spleen cells and recipients share the K or the D region of the H-2 gene complex. I region compatibility is neither necessary nor sufficient. The F1 → Parent combination is as effective as a syngeneic system. Admixture of a 6-fold excess of immune allogeneic cells did not impair the protective effect exerted by syngeneic immune spleen cells in vivo. Furthermore, allogeneic spleen cells or target cells added in syngeneic systems in vitro did not allogeneicly inhibit or suppress cytolytic activity. H-2 mutant mice B6.H-2 bf did not protect wild type H-2K b B10.A(5r) or vice versa. Therefore, these mice define the gene(s) coding for the relevant cell-surface structure involved. These results are consistent with the idea that immune T cells, which are specific for virally altered cell-surface self structures impair virus growth in vivo either by lysing target cells, probably before infectious virus is released, or alternatively via activities exerted by lymphokines.