Immunological characteristics of CD103⁺CD8⁺ Tc cells in the liver of C57BL/6 mouse infected with plasmodium NSM

CD103 is an important marker of tissue-resident memory T cells (TRM) which play important roles in fighting against infection. However, the immunological characteristics of CD103(+) T cells are not thoroughly elucidated in the liver of mouse infected with Plasmodium. Six- to eight-week-old C57BL/6 mice were infected with Plasmodium yoelii nigeriensis NSM. Mice were sacrificed on 12-16 days after infection and the livers were picked out. Sections of the livers were stained, and serum aspartate aminotransferase (AST) and alanine transaminase (ALT) levels were measured. Moreover, lymphocytes in the liver were isolated, and the expression of CD103 was determined by using qPCR. The percentage of CD103 on different immune cell populations was dynamically observed by using flow cytometry (FCM). In addition, the phenotype and cytokine production characteristics of CD103(+)CD8(+) Tc cell were analyzed by using flow cytometry, respectively. Erythrocyte stage plasmodium infection could result in severe hepatic damage, a widespread inflammatory response and the decrease of CD103 expression on hepatic immune cells. Only CD8(+) Tc and gamma delta T cells expressed higher levels of CD103 in the uninfected state.CD103 expression in CD8(+) Tc cells significantly decreased after infection. Compared to that of CD103(-) CD8(+) Tc cells, CD103(+) CD8(+) Tc cells from the infected mice expressed lower level of CD69, higher level of CD62L, and secreted more IL-4, IL-10, IL-17, and secreted less IFN-gamma. CD103(+)CD8(+) Tc cells might mediate the hepatic immune response by secreting IL-4, IL-10, and IL-17 except IFN-gamma in the mice infected with the erythrocytic phase plasmodium, which could be involved in the pathogenesis of severe liver damage resulted from the erythrocytic phase plasmodium yoelii nigeriensis NSM infection.