Changes of CD103-expressing pulmonary CD4+ and CD8+ T cells in S. japonicum infected C57BL/6 mice.

<bold>Background: </bold>Recent studies have shown that CD103 is an important marker for tissue-resident memory T cells (TRM) which plays an important role in anti-infection. However, the role of CD103+ TRM was not elucidated in the progress of S. japonicum infection induced disease.<bold>Methods: </bold>6-8 weeks old C57BL/6 mice were infected by S. japonicum. Mice were sacrificed and the lungs were removed 5-6 weeks after infection. Immunofluorescent staining and Q-PCR were performed to identify the expression of CD103 molecule. Single cellular populations were made, percentages of CD103 on both CD4+ and CD8+ T lymphocytes were dynamical observed by flow cytometry (FCM). Moreover, the expression of memory T cells related molecules CD69 and CD62L, T cell function associated molecules CD107a, IFN-γ, IL-4, IL-9, and IL-10 were compared between CD103+ CD4+ and CD8+ T cells by FCM.<bold>Results: </bold>CD103+ cells were emerged in the lung of both naive and S. japonicum infected mice. Both the percentage and the absolute numbers of pulmonary CD4+ and CD8+ cells were increased after S. japonicum infection (P < 0.05). The percentage of CD103+ cells in CD8+ T cells decreased significantly at the early stage of S. japonicum infection (P < 0.05). Increased CD69, decreased CD62L and CD107a expressions were detected on both CD4+ and CD8+ CD103+ T cells in the lungs of infected mice (P < 0.05). Compared to CD8+ CD103+ T cells, CD4+ CD103+ T cells from infected mice expressed higher level of CD69 and lower level CD62L molecules (P < 0.05). Moreover, higher percentage of IL-4+, IL-9+ and IL-10+ cells on CD4+ CD103+ pulmonary T cells was found in infected mice (P < 0.05). Significantly increased IL-4 and IL-9, and decreased IFN-γ expressing cells were detected in CD8+CD103+ cells of infected mice (P < 0.05).<bold>Conclusions: </bold>CD103-expressing pulmonary CD4+ and CD8+ T cells play important roles in mediating S. japonicum infection induced granulomatous inflammation in the lung. [ABSTRACT FROM AUTHOR]