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Published on: December 23, 2016
Phenotypic changes in peripheral blood monocytes of cynomolgus monkeys acutely infected with simian immunodeficiency
1Tsukuba Primate Center, National Institute of Infectious Diseases, Ibaraki, Japan.
Abstract:
The quantitative and phenotypic changes of peripheral blood monocytes during the acute stage of simian immunodeficiency virus infection were investigated. We inoculated intravenously three cynomolgus monkeys (Macaca fascicularis) with 100 TCID50 of SIVmac239 and collected whole blood twice a week until 35 days postinoculation. We found that the relative number of monocytes in peripheral blood leukocytes significantly increased at 7-17 days postinoculation. This increase was concomitant with the peak of primary SIV antigenemia. To determine if the monocytes observed during the acute stage were phenotypically altered, they were periodically examined for the expression of surface markers (i.e., CD11b, CD14, CD16, CD29, D32, CD56, CD62L, CD64, CD80, and MHC-II-DR) by flow cytometry. The results showed that the expression levels of CD14 and CD56 on most of the monocytes were remarkably reduced at 7-17 days postinoculation, and a new subpopulation, CD14lowCD16+CD80+ monocytes, was clearly detected at 10 days postinoculation. These results indicate that the phenotypic alteration of peripheral blood monocytes occurs during the primary SIV infection.
Insights
Peripheral blood monocytes increase during acute simian immunodeficiency virus (SIV) infection. Phenotypic changes, including reduced CD14 and CD56 expression, occur in these monocytes.
Area of Science:
- Immunology
- Virology
- Primate Models
Background:
- Simian immunodeficiency virus (SIV) infection in macaques serves as a model for human immunodeficiency virus (HIV) infection.
- Monocytes play a crucial role in immune responses and are affected during viral infections.
Purpose of the Study:
- To investigate the quantitative and phenotypic changes of peripheral blood monocytes during the acute stage of SIV infection in cynomolgus monkeys.
- To characterize the alterations in monocyte surface marker expression following SIV inoculation.
Main Methods:
- Intravenous inoculation of cynomolgus monkeys with SIVmac239.
- Collection of peripheral blood samples twice weekly for 35 days post-inoculation.
- Flow cytometry analysis of monocyte surface markers (CD11b, CD14, CD16, CD29, D32, CD56, CD62L, CD64, CD80, MHC-II-DR).
Main Results:
- A significant increase in the relative number of peripheral blood monocytes was observed between 7-17 days post-inoculation, coinciding with peak SIV antigenemia.
- Reduced expression of CD14 and CD56 on monocytes was noted during the same period.
- A distinct subpopulation of CD14lowCD16+CD80+ monocytes emerged at 10 days post-inoculation.
Conclusions:
- Peripheral blood monocytes undergo significant quantitative and phenotypic alterations during the acute phase of SIV infection.
- These changes suggest a role for monocytes in the early immune response to SIV and potential involvement in viral pathogenesis.
