Immune phenotype of the CD4+ T cells in the aged lymphoid organs and lacrimal glands

Aging is associated with a massive infiltration of T lymphocytes in the lacrimal gland. . Among the non-Tregs, we also found a significant increase in the levels of EOMESmed/high, TbetnegIFN-𝛄+ and CD62L+CD44neg CD4+ T cells with aging, which are associated with cell exhaustion, immunopathology and the generation of tertiary lymphoid tissue. More importantly, human lacrimal glands (age range 55-81 years) also showed presence of CD4+Foxp3+ cells. Further studies are needed to propose potential molecular targets to avoid immune-mediated lacrimal gland dysfunction with aging. Here we aimed to characterize the immune phenotype of aged CD4+ T cells in this tissue as compared with lymphoid organs. To perform this, we sorted regulatory T cells (Tregs, CD4+CD25+GITR+) and non-Tregs (CD4+CD25negGITRneg) cells and subjected these cells to an immunology NanoStringⓇ panel in lymphoid organs. These results were confirmed by flow cytometry, live imaging and tissue immunostaining in the lacrimal gland. Importantly, effector T helper 1 (Th1) genes were highly upregulated on aged Tregs, including the master regulator Tbx21 Cells from eye and lacrimal gland draining lymph nodes were pooled with splenocytes. Cells were stained and sorted based on the expression of CD4+CD25+GITR+ (Tregs, or DP) and compared to CD4+CD25-GITR- (non-Tregs). After sorting, cells were lysed in RNA, total RNA was isolated and NanoString was performed.