摘要:

ABSTRACTIsolation of infectious viruses from the brain during a chronic neurological disease is infrequent because persistent viruses differ from the parental virus in their virulence and in the development in genomic or replication defects. We have isolated mouse hepatitis virus 3 (MHV3) variants from the brain of chronically infected mice up to 105 days postinfection by culture on overconfluent L2 cells. In spite of atrophy and leukopenia observed in lymphoid organs of these mice, no viruses were isolated in numerous attempts. In contrast, defective-interfering viruses were detected in peritoneal exudate cells from chronically-infected mice. Brain-derived viruses differ from parental virus in their delayed fusion activity and attenuated pathogenicity for C57BL/6 and A/J mice. The attenuated brain isolates have ceased to replicate in thymocytes but replicated in nonadherent spleen and peritoneal exudate cells.

ISSN:0882-8245    

DOI:10.1089/vim.1990.3.1

年代:1990

数据来源: MAL

摘要:

ABSTRACTTo study the role of the T-3/T-cell receptor complex in mediating natural killer activity, we have examined T-cell receptor gene configuration and expression in five transformed marmoset cell lines with natural killer activity. All lines showed rearrangement of the beta chain of the T-cell receptor and expressed full size beta chain transcripts as well as full size delta chain transcripts. Only three lines contained full size T-cell receptor alpha chain transcripts. Of the three lines which had potential for encoding functional T-3/T-cell receptor complex, those which possessed natural killer activity also expressed T-gamma transcripts. In addition, one clone with high natural killer activity which did express high levels of T-gamma mRNA was unable to produce functional T-3/T-cell receptor complex due to truncated T-cell receptor alpha chain message. The results in this paper provide strong evidence that natural killer activity is dependent upon expression of the T-cell receptor gamma chain.

ISSN:0882-8245    

DOI:10.1089/vim.1990.3.9

年代:1990

数据来源: MAL

摘要:

ABSTRACTThe correlation between skin reaction, exhibited by vaccinees immunized against smallpox, and antibody titer determined by plaque neutralization and ELISA, was evaluated. Twenty eight out of 35 young adults (vaccinated at infancy and at the age of 8 years), who were injected with vaccinia virus, displayed a major skin reaction a week later. An increase of four–folds and more, in antibody titer against vaccinia virus, is generally considered positive immunization take–up against smallpox. According to this criterion, only 17 of the vaccinees were found positive by plaque neutralization, while 25 by the indirect micro–ELISA. Thus, there were eight vaccinees who were considered immunized by the ELISA, (seven of them also according to the skin reaction), but not by the plaque neutralization

ISSN:0882-8245    

DOI:10.1089/vim.1990.3.19

年代:1990

数据来源: MAL

摘要:

ABSTRACTB-lymphocyte activation was studied in mice infected with lactate dehydrogenase-elevating virus (LDV). ELISA determinations of blood total immunoglobulin levels demonstrated that, at 10 days post-infection (p.i.) with LDV, only the IgG2a isotype was elevated. DNA-excess dot-blot hybridization showed that RNA specific for IgG2a and IgA immunoglobulin isotypes was increased in the spleens of mice at 10 days p.i. with LDV. Immunoglobulin surface phenotype analysis of spleen cells at 8-10 days p.i. with LDV revealed that there was no alteration in immunoglobulin isotype-bearing cell proportions, although total spleen mass and number of cells increased during LDV infection. When blood immunoglobulins from LDV-infected mice were analyzed by two-dimensional isoelectric focusing gels, followed by specific immunoblotting for immunoglobulin isotype, the presence of new IgG2a species was observed at 10 days p.i.

ISSN:0882-8245    

DOI:10.1089/vim.1990.3.27

年代:1990

数据来源: MAL

摘要:

ABSTRACTThree T cell clones derived from rabies virus-immunized BALB/c mice were analysed for specificity and function. The clones proved to be broadly cross-reactive by responding to different rabies virus isolates (PM, ERA, CVS, HEP) and other representatives of the genus Lyssavirus, like the Duvenhage-6 (DUV6) and Mokola (MOK) viruses. The clones detected three different epitopes: an epitope expressed on the matrix protein (M) shared by PM, HEP, MOK and DUV6 viruses (clone AA8), an epitope expressed on the M-protein shared by PM, ERA, CVS, HEP and MOK viruses (clone 35A) and finally an epitope expressed on the glycoprotein (G-protein) shared by PM, ERA, CVS, HEP and MOK viruses (clone BG2). Antigen recognition of all clones proved to be MHC-restricted and they all displayed the CD4+CD8-phenotype. Intravenous inoculation of the T cells in syngeneic mice, which had been injected intracutaneously in the ear with HEP virus, resulted in a localized DTH reaction characteristic for TH1 cells. In vitro, the clones were able to provide help to rabies virus-primed B cells, resulting in the production of virus-specific antibodies directed against all the four structural proteins of rabies virus. Further analysis of this antibody response revealed that part of it was directed against antigenic determinants of the G-protein which induce virus neutralizing antibody.

ISSN:0882-8245    

DOI:10.1089/vim.1990.3.41

年代:1990

数据来源: MAL

摘要:

ABSTRACTEpstein-Barr virus (EBV) readily immortalizes human peripheral blood lymphocytes (PBL) in vitro. We found recently that PBL from two EBV-seropositive healthy adults were exceptionally resistant to immortalization by EBV. In contrast to PBL from other EBV-seropositive donors sensitive to immortalization by EBV (S-PBL), the "resistant" PBL (R-PBL) respond to EBV infection with an early interleukin-2 (IL-2) synthesis and high interferon gamma (IFNγ) production. In order to determine whether these differences in cytokine responses between R-PBL and S-PBL could be associated with a detectable difference in lymphocyte cytotoxicity, we compared the natural killer (NK) activity of R-PBL and S-PBL effectors by using both NK-sensitive (i.e. K562) and NK-resistant (i.e. Raji) targets.We found that, while effectors from EBV-infected R-PBL and S-PBL cultures exhibited comparable NK activity against the K562 targets, they differed remarkably in their cytolytic activity against Raji cells. At days 3 and 5 of culture, effectors from EBV-infected R-PBL showed a significantly higher lytic activity against Raji targets, whereas S-PBL did not. Culture of EBV-infected R-PBL and S-PBL effectors in the presence of recombinant IL-2 (rIL-2) for 5 days resulted in increases of their lytic activity against Raji cells, whereas pretreatment of these effectors with recombinant IFNγ(rIFNγ) was found to increase only the R-PBL cytotoxicity. These results suggest that the resistance of R-PBL to EBV immortalization could be associated with a lymphokine-mediated early cellular cytotoxic response of the NK/LAK (lymphokine-activated killer cell) type against EBV-infected cel

ISSN:0882-8245    

DOI:10.1089/vim.1990.3.55

年代:1990

数据来源: MAL

摘要:

ABSTRACTThe involvement of natural killer (NK) cells in the development of diabetes in the normally resistant 9-10 week old C57BL/6J male mice by the D variant of encephalomyocarditis virus (EMCV-D) was examined. Inoculation of purified EMCV-D induced maximum NK cell activity in splenic cell populations on day 4 post-inoculation as determined by lysis of YAC-l target cells in a standard51chromium release microcytotoxicity assay. Selective depletion of NK cells by the administration of rabbit anti-asialo GMlsera prior to challenging the C57BL/6J mice with EMCV-D, resulted in diminished splenic NK cell activity, increased EMCV-D viral titers in the pancreas, spleen, heart and brain, and the induction of diabetes in 60-80% of the mice. The data suggest that NK cells play a role in host protection against the diabetogenic EMCV-D.

ISSN:0882-8245    

DOI:10.1089/vim.1990.3.67

年代:1990

数据来源: MAL

摘要:

ABSTRACTMurine anti-reovirus cytotoxic T lymphocytes (CTLs) were analyzed for H-2 restricted recognition of virus infected target cells and for potential cross-reactivity with cells infected by reovirus serotype 1 (T1; Lang strain) or by serotype 3 (T3; Dearing strain). Anti-reovirus CTL specifically lysed virus infected cells and lysis was shown to be H-2 restricted by the H-2Dd, H-2Ld, H-2Kd, H-2Kb, and H-2Kkantigens. No H-2 antigens were identified which failed to restrict virus recognition by anti-reovirus CTL. Anti-T1 and anti-T3 CTLs were also shown to crossreact completely with cells infected with the opposite virus serotype. Thus, anti-reovirus CTLs are restricted by a broad spectrum of H-2 antigens and they detect common rather than unique structural components of these two viral serotypes.

ISSN:0882-8245    

DOI:10.1089/vim.1990.3.77

年代:1990

数据来源: MAL