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Specificity of helper T-cells generated from macaques infected with attenuated simian immunodeficiency virus
U Dittmer1, G Feldmann, U Sauermann
1Deutsches Primatenzentrum, Virologie und Immunologie, Göttingen, Germany. udittmer@atlas.niaid.nih.gov
Abstract:
Deletion of the simian immunodeficiency virus (SIV) nef gene leads to an attenuated virus phenotype in vivo. We have previously shown that these viruses induce a potent cellular immune response in macaques. To extend these studies, we established virus-specific short-term T-cell lines from four rhesus macaques infected with a nef deletion mutant of SIV. These T-cell lines proliferated upon restimulation with whole SIV or SIV gp140 antigen in vitro. The proliferating cells were characterized as CD4+ helper T-cells (TH) and their antigen recognition was MHC class II DR-restricted. After antigenic stimulation, they transcribed mRNA for various TH1- and TH2-like cytokines. Using these SIV-specific cell lines, a variety of helper T-cell epitopes in the SIV Env protein were determined with overlapping peptides. TH epitopes were identified throughout the whole SIV Env including both constant and variable regions. Although the recognition of TH epitopes was heterogeneous among different animals, five more broadly reactive T-cell epitopes were identified. As expected, recognition was associated with the MHC class II DRB background of the animals. This is the first report on helper T-cell epitopes in SIV-infected monkeys. Such studies should be of considerable significance for AIDS/ vaccine research.
Insights
Simian immunodeficiency virus (SIV) nef deletion mutants induce a strong cellular immune response. Researchers identified novel helper T-cell epitopes in the SIV Env protein, crucial for AIDS vaccine development.
Area of Science:
- Immunology
- Virology
- Vaccinology
Background:
- Simian immunodeficiency virus (SIV) nef gene deletion results in an attenuated virus with a potent cellular immune response in vivo.
- Previous studies demonstrated that these nef-deleted SIV mutants elicit a strong cellular immune response in macaques.
Purpose of the Study:
- To establish and characterize virus-specific T-cell lines from SIV-infected rhesus macaques.
- To identify helper T-cell epitopes within the SIV Env protein using these established T-cell lines.
Main Methods:
- Generation of short-term, SIV-specific T-cell lines from rhesus macaques infected with a nef deletion mutant SIV.
- In vitro proliferation assays using whole SIV or SIV gp140 antigen for restimulation.
- Characterization of T-cell populations (CD4+ helper T-cells) and their cytokine mRNA transcription (TH1/TH2-like).
- Epitope mapping using overlapping peptides to identify T-helper cell epitopes within the SIV Env protein, with MHC class II DR restriction analysis.
Main Results:
- Established SIV-specific CD4+ helper T-cell lines that proliferated upon antigen stimulation.
- Identified helper T-cell epitopes across the SIV Env protein, including constant and variable regions.
- Discovered five broadly reactive T-cell epitopes, with recognition linked to the animals' MHC class II DRB background.
- Demonstrated antigen recognition was MHC class II DR-restricted.
Conclusions:
- This study reports the first identification of helper T-cell epitopes in SIV-infected non-human primates.
- The identified epitopes are located throughout the SIV Env protein and are MHC class II DR-restricted.
- These findings have significant implications for understanding SIV pathogenesis and developing AIDS vaccines.