ISSN:0882-8245    

DOI:10.1089/vim.1998.11.1

年代:1998

数据来源: MAL

摘要:

ABSTRACTIn a previous study, we demonstrated that by downregulating plasma membrane CD4 and increasing its processing, human immunodeficiency (HIV)-1-gp120 unveils hidden CD4 epitopes, inducing anin vitroanti-CD4-specific T-cell response. We report herein that this mechanism may potentially have important implications in HIV immunopathogenesis, because it could take part in the severe depletion of CD4+cells that characterizes acquired immune deficiency syndrome (AIDS) and be related to disease progression. Freshly isolated peripheral blood lymphocytes (PBMC) from about 1/4 of a conspicuous cohort of HIV-infected patients responded to CD4 and this response was correlated with β2-microglobulin levels, widely recognized as marker for progression of HIV infection. Moreover, we provide evidence that a CD4-specific T cell priming can occurin vivo, following a gp120 or anti-CD4 monoclonal antibody (mAb)-mediated CD4 molecule downregulation on antigen-presenting cells (APC). To our knowledge, this is the first study indicating that an autoimmune T-cell response is linked to HIV infection and that it could have an important impact on the immunopathogenesis of this disease

ISSN:0882-8245    

DOI:10.1089/vim.1998.11.9

年代:1998

数据来源: MAL

摘要:

ABSTRACTWe investigated the immune reaction of lymphocytes in response to human herpes virus-6 (HHV-6) in normal children and adults. Cell proliferation was assayed by measurement of the incorporation of 5-bromo-2′-deoxyuridine (BrdU) by enzyme-linked immunosorbent assay (ELISA), and changes in expression of interleukin-2 receptors (IL-2Rs) (α-, β-, and γ-chain) were assayed by flow cytometry. Incorporation of BrdU and expression of IL-2Rs (α-, β-, and γ-chain) in CD4+, CD8+, and CD45RO+lymphocytes were increased when peripheral blood mononuclear cells (PBMC) from HHV-6 seropositive children aged 3 to 12 years and adults were cultured with HHV-6 antigen compared with control antigen. In contrast, cord blood mononuclear cells (CBMC) and PBMC from seronegative children did not show cell proliferation and changes in expression of IL-2Rs. In seropositive children less than 2 years of age, the magnitude of cell proliferation was low and IL-2Rs (α-, β-, and γ-chain) in CD8+cells and IL-2Rs (α-chain) in CD45RO+cells were increased. These data suggest that children below the age of 2 had immature lymphocytic response to HHV-6 antigen. Deletion of monocytes from PBMC and the addition of a mixture of anti-IL-2Rs (α-, β-, and γ-chain) antibodies reduced cell proliferation in response to HHV-6, suggesting the requirement of the presence of monocytes and expres

ISSN:0882-8245    

DOI:10.1089/vim.1998.11.19

年代:1998

数据来源: MAL

摘要:

ABSTRACTAn earlier study in our laboratory provided evidence that pseudorabies virus (PrV) immediate early protein (IE180) may contribute to the overall immune response against PrV. To examine the response by IE180 more closely, we initiated a vaccine trial in mice with a vector DNA construct that contains the gene encoding for IE180, designated pcDNAIE180. The DNA vaccine was delivered in gold microcarriers using a Helios Gene Gun, and 70% of BALB/c mice given the DNA vaccine (2 μg/mouse) seroconverted within 2 weeks. The remaining negative mice seroconverted after a single vaccine booster. Essentially similar results were obtained on vaccination of C57BL/6 mice, whereas C3H/HeJ mice remained negative after the first vaccination, but responded after a booster. Seven months after immunization with pcDNAIE180, an overall 25% of BALB/c, C3H/HeJ, and C57BL/6 mice receiving a lethal PrV challenge were protected. In addition, a significant passive transfer of IE180-specific antibodies to the offspring from pregnant mice vaccinated with pcDNAIE180 was observed. Interestingly, a moderate level of protection (27.6%) was also observed when these offspring received a lethal PrV challenge. Moreover, an enhancement of immune responses and a twofold increase in the level of protection were observed in mice that received a second vaccine booster by gene gun 8 months after the first vaccination. Together, these data support the theory that IE180 may indeed play a role in the overall protective immunity against PrV

ISSN:0882-8245    

DOI:10.1089/vim.1998.11.27

年代:1998

数据来源: MAL

摘要:

ABSTRACTThe study of T-cell-mediated cytotoxicity in domestic animals, especially in cattle, has been hampered by the lack of proper restimulatory as well as target systems. While the currently available bovine cell lines have not been typed for the major histocompatibility complex (MHC) class I molecules they express, methods to derive lines of cells obtained from animals that are MHC-typed have not been thoroughly explored. In the present study, we describe a method for the development of cell lines from MHC-typed animals. Cells obtained from the skin of a calf typed as bovine lymphocyte antigen-A11/-A13 were transfected with a plasmid containing the whole genome of simian vacuolating virus 40 (SV40). A cell line was derived from the resultant transfectants. This cell line expressed bovine MHC class I molecules on the cell surface, and SV40 large T antigen in the nucleus. The cells were permissive to the replicative cycle of bovine herpesvirus-1 (BHV-1), and the major glycoproteins of BHV-1 were expressed at expected times after infection. The present study should contribute to the study of cytotoxic T lymphocyte response of cattle to BHV-1 and other intracellular pathogens.

ISSN:0882-8245    

DOI:10.1089/vim.1998.11.37

年代:1998

数据来源: MAL

摘要:

ABSTRACTA colorimetric assay for titration of neutralizing antibodies against vaccinia virus was developed. The test is based on the ability of live cells in culture to reduce the yellow tetrazolium salt MTT (thiazolyl-blue), to its blue formazan derivative. Antisera from individuals vaccinated with vaccinia virus against smallpox were serially diluted, incubated with 100 plaque-forming units (PFU) of vaccinia virus for 1 hour at 37°C, and then transferred to a 96-well plate containing monolayers of B-SC-1 cells. After incubation for 3 to 4 days at 37°C, when more than 80% of the control infected cultures exhibited high degree of cytopathogenic effect, MTT was added. The absorbance of the formazan formed and extracted by dimethylsulfoxide was read at 492 nm by an automatic microplate spectrophotometer. A good correlation was found between the results obtained using this newly developed method and those of the plaque-reduction assa

ISSN:0882-8245    

DOI:10.1089/vim.1998.11.49

年代:1998

数据来源: MAL