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Analysis of Simian Immunodeficiency Virus-specific CD8+ T-cells in Rhesus Macaques by Peptide-MHC-I Tetramer Staining
Published on: December 23, 2016
Experimental inoculation of juvenile rhesus macaques with primate enteric caliciviruses
Karol Sestak1, Stephanie Feely, Brittney Fey
1Tulane National Primate Research Center, Covington, Louisiana, United States of America. ksestak@tulane.edu
Background:
Tissue culture-adapted Tulane virus (TV), a GI.1 rhesus enteric calicivirus (ReCV), and a mixture of GII.2 and GII.4 human norovirus (NoV)-containing stool sample were used to intrastomacheally inoculate juvenile rhesus macaques (Macaca mulatta) in order to evaluate infection caused by these viruses. METHODOLOGY & FINDINGS: Two of the three TV-inoculated macaques developed diarrhea, fever, virus-shedding in stools, inflammation of duodenum and 16-fold increase of TV-neutralizing (VN) serum antibodies but no vomiting or viremia. No VN-antibody responses could be detected against a GI.2 ReCV strain FT285, suggesting that TV and FT285 represent different ReCV serotypes. Both NoV-inoculated macaques remained asymptomatic but with demonstrable virus shedding in one animal. Examination of duodenum biopsies of the TV-inoculated macaques showed lymphocytic infiltration of the lamina propria and villous blunting. TV antigen-positive (TV+) cells were detected in the lamina propria. In most of the TV+ cells TV co-localized perinuclearly with calnexin--an endoplasmic reticulum protein. A few CD20+TV+ double-positive B cells were also identified in duodenum. To corroborate the authenticity of CD20+TV+ B cells, in vitro cultures of peripheral blood mononuclear cells (PBMCs) from healthy macaques were inoculated with TV. Multicolor flow cytometry confirmed the presence of TV antigen-containing B cells of predominantly CD20+HLA-DR+ phenotype. A 2-log increase of viral RNA by 6 days post inoculation (p<0.05) suggested active TV replication in cultured lymphocytes.
Conclusions/Significance:
Taken together, our results show that ReCVs represent an alternative cell culture and animal model to study enteric calicivirus replication, pathogenesis and immunity.
Insights
Rhesus enteric caliciviruses (ReCVs), including Tulane virus (TV), can infect macaques, causing gastrointestinal illness and immune responses. These findings establish ReCVs as a valuable model for studying enteric calicivirus replication and immunity.
Area of Science:
- Virology
- Immunology
- Gastroenterology
Background:
- Enteric caliciviruses, such as Tulane virus (TV) and human noroviruses (NoV), are significant causes of gastroenteritis.
- Rhesus enteric calicivirus (ReCV) and human NoV strains were used to infect juvenile rhesus macaques to evaluate pathogenesis and immune responses.
Purpose of the Study:
- To assess the infectivity and pathogenicity of Tulane virus (TV) and human noroviruses (NoV) in a rhesus macaque model.
- To investigate the immune responses, including antibody production and viral replication, in macaques infected with enteric caliciviruses.
Main Methods:
- Intrastomachical inoculation of macaques with tissue culture-adapted TV and a mixture of human NoV strains.
- Clinical observation, virological analysis (stool shedding, viremia), serological assays (neutralizing antibodies), and histopathological examination of duodenal tissues.
- In vitro culture of peripheral blood mononuclear cells (PBMCs) with TV, followed by multicolor flow cytometry to analyze viral antigen-containing B cells.
Main Results:
- TV inoculation led to diarrhea, fever, duodenal inflammation, and increased TV-neutralizing serum antibodies in macaques.
- No cross-neutralizing antibody responses were observed between TV and a GI.2 ReCV strain, suggesting distinct serotypes.
- TV antigen-positive cells, including B cells, were identified in duodenal tissues and confirmed in cultured PBMCs, indicating active viral replication in lymphocytes.
Conclusions:
- Rhesus enteric caliciviruses (ReCVs), exemplified by TV, can establish infection and elicit immune responses in macaques.
- The rhesus macaque model provides a valuable platform for studying the replication, pathogenesis, and immunity of enteric caliciviruses.
- TV and other ReCVs represent a promising alternative model for enteric calicivirus research.
