High content cellular immune profiling reveals differences between rhesus monkeys and men

P>A better understanding of similarities and differences in the composition of the cellular immune system in non-human primates (NHPs) compared with human subjects will improve the interpretation of preclinical studies. It will also aid in addressing the usefulness of NHPs as subjects for studying chronic diseases, vaccine development and immune reconstitution. We employed high content colour flow cytometry and analysed simultaneously the expression of CD3, CD4, CD8 alpha, CD8 beta, CD16/CD56, CD45RA, CCR7, CD27, CD28, CD107a and the interleukin-7 receptor alpha-chain (IL-7R alpha) in peripheral blood mononuclear cells (PBMCs) of 27 rhesus macaques and 16 healthy human subjects. Regulatory T cells (Tregs) were identified using anti-CD3, -CD4, -CD25, -FoxP3, and -IL-7R alpha monoclonal antibodies. Responsiveness to IL-7 was gauged in a signal transducer and activation of transcription 5 (STAT-5) phosphorylation assay. Human and NHP PBMCs showed a similar T-cell composition pattern with some remarkable differences. Similarities: human and NHP CD4+ and CD8+ cells showed a similar STAT-5 phosphorylation pattern in response to IL-7. Multicolour flow cytometric analysis identified a CD4+ CD8 alpha alpha+ CD8 alpha beta+ T-cell population in NHPs as well as in human subjects that expressed the degranulation marker CD107a and may represent a unique CD4+ T-cell subset endowed with cytotoxic capacity. Differences: we identified in PBMCs from NHPs a higher proportion (5 center dot 16% in CD3+ T cells) of CD8 alpha alpha+ T cells when compared with human donors (1 center dot 22% in CD3+ T cells). NHP CD8 alpha alpha+ T cells produced tumour necrosis factor-alpha / interferon-gamma (TNF-alpha/IFN-gamma) or TNF-alpha, whereas human CD8 alpha alpha+ T cells produced simultaneously TNF-alpha/IFN-gamma and IL-2. A minor percentage of human CD8+ T cells expressed CD25bright and FoxP3 (0 center dot 01%). In contrast, 0 center dot 07% of NHP CD8+ T cells exhibited the CD25bright FoxP3+ phenotype. PBMCs from NHPs showed less IL-7R alpha-positive events in all T-cell subsets including CD4+ Tregs (median 5%) as compared with human (median 12%). The data visualize commonalities and differences in immune cell subsets in humans and NHPs, most of them in long-lived memory cells and cells with suppressive functions. This provides a matrix to assess future efforts to study diseases and vaccines in NHPs.