Indoleamine 2,3-dioxygenase is differentially expressed by different white blood cell populations of rhesus macaques (Macaca mulatta)

摘要

Background Indoleamine 2,3-dioxygenase (IDO) is involved in immune processes such as transplant and fetal rejection, autoimmunity, cancer, and infection; however, its expression in rhesus macaques has not been fully addressed. Methods Indoleamine 2,3-dioxygenase mRNA and protein in the white blood cells (WBCs) of Chinese rhesus macaques were examined by RT-PCR, western blotting, real-time RT-PCR, and flow cytometry. Results Both IDO protein and mRNA could be readily detected in WBCs or peripheral blood mononuclear cells (PBMCs) of normal rhesus macaques. IDO~+ cell frequency was the highest among CD14~+ mononuclear cells, followed by CD56~+ cells and DCs. No difference in the frequency of IDO~+ cells between CD4~+ and CD8~+ T cells; however, Th17 cells have higher frequency of IDO~+ cells than Th1 cells, with Th2 cells the lowest. Toll-like receptor (TLR) stimulation significantly increased IDO protein level in CD14~+, CD56~+, CD1c~+, CD11c~+, and CD123~+ myeloid cells. Conclusion Rhesus macaques express IDO differentially in their leukocyte subsets and are suitable for IDO-related pathophysiological studies.