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Updated: Jul 8, 2026
Analysis of Simian Immunodeficiency Virus-specific CD8+ T-cells in Rhesus Macaques by Peptide-MHC-I Tetramer Staining
Published on: December 23, 2016
Novel application of nonhuman primate tethering system for evaluation of acute phase SIVmac251 infection in rhesus
M Shannon Keckler1, Vida L Hodara, Laura M Parodi
1University of Texas Health Science Center at San Antonio, Texas., Department of Virology and Immunology, San Antonio, Texas, USA.
Abstract:
Infection of rhesus macaques with simian immunodeficiency virus (SIV) is the preferred animal model for the development and testing of human immunodeficiency virus (HIV) vaccines, and animals protected from SIV challenge by live attenuated vaccines are an invaluable tool for determining immune correlates of protection. The acute phase of SIV infection, in which immune responses are most critical for slowing disease progression, occurs within the first 4 weeks of exposure. The small window of time available for observing critical immune responses makes obtaining adequate blood samples with sufficient frequency difficult. This study is the first to apply a previously reported nonhuman primate (NHP) tether system to study viral immunology. The use of the tether allows for frequent blood sampling without using restraints or sedation, thereby reducing the potentially confounding physiological changes induced by stress. We performed comparative analysis of acute phase immune responses in vaccinated and unvaccinated animals challenged with SIV-mac251. Our results demonstrate live attenuated vaccine-induced protection, which is associated with small increases in the cytotoxic T-cell (CTL) response to immunodominant epitopes, but not with increases in antibody titers. Additionally, vaccination was shown to establish a pool of antigen-specific CD8+ memory cells available for expansion after challenge. The confirmatory nature of these data indicates the validity of using the tether system for evaluation of acute phase anti-SIV responses and can be applied to the study of immune responses in other viral infections in which frequent sampling in small windows of time would be useful.
Insights
A novel tether system allows frequent blood sampling in rhesus macaques during simian immunodeficiency virus (SIV) infection. This method aids in understanding early immune responses crucial for developing effective human immunodeficiency virus (HIV) vaccines.
Area of Science:
- Veterinary immunology
- Vaccinology
- Primate models
Background:
- Simian immunodeficiency virus (SIV) infection in rhesus macaques is a key model for human immunodeficiency virus (HIV) vaccine development.
- The acute phase of SIV infection (first 4 weeks) is critical for immune responses but difficult to study due to limited sampling windows.
- Stress from conventional blood sampling methods can confound immunological studies in nonhuman primates (NHPs).
Purpose of the Study:
- To evaluate a nonhuman primate (NHP) tether system for frequent blood sampling during the acute phase of SIV infection.
- To compare acute phase immune responses in vaccinated versus unvaccinated macaques challenged with SIV.
- To identify immune correlates of protection induced by live attenuated SIV vaccines.
Main Methods:
- Application of a nonhuman primate (NHP) tether system for serial blood collection without sedation or restraint.
- Comparative analysis of immune responses, including cytotoxic T-cell (CTL) and antibody titers, in vaccinated and unvaccinated SIV-challenged macaques.
- Assessment of antigen-specific CD8+ memory cell populations post-challenge.
Main Results:
- The NHP tether system facilitated frequent blood sampling, reducing stress-induced physiological changes.
- Live attenuated vaccine-induced protection correlated with minor increases in cytotoxic T-cell (CTL) responses, not antibody titers.
- Vaccination established a reservoir of antigen-specific CD8+ memory cells poised for expansion upon SIV challenge.
Conclusions:
- The NHP tether system is a valid and valuable tool for studying acute anti-SIV immune responses.
- This method can be applied to other viral infections requiring frequent sampling within short timeframes.
- Findings support the use of live attenuated vaccines and highlight CTL responses and memory cell pools as key correlates of protection.
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