Chicken Peripheral Blood CD3⁺CD4^-CD8^- Cells are Regulated by Endocrine and Nerve Systems

Abstract

The existence of CD3⁺CD4^-CD8^- T cells in thymus and spleen has already been known. However, because of the presence of large amounts of thrombocytes in peripheral blood (PB), the proportion of CD3⁺CD4^-CD8^- T cells in PB has yet to be investigated. Therefore, the proportion of peripheral T cell-subsets was investigated in 6-week-old chickens. The percentage of CD3⁺ cells, CD4⁺ cells, CD8α⁺ cells, CD8β⁺, and CD3⁺CD4^-CD8^- cells was 76%, 41%, 14%, 5%, and 15%, respectively. The proportion of CD3⁺CD4^-CD8^- cells in PB increased during egg-laying periods and in chickens treated with an analog of estrogen, while it decreased with age and in response to restraint stress. All of the CD3⁺CD4^-CD8^- cells expressed TCR1, and did not have NK activity. CD3⁺CD4^-CD8^- cells represent about 60% of peripheral TCR1⁺ cells. These findings indicate that the proportion of CD3⁺CD4^-CD8^- cells is regulated by the endocrine and nerve systems.