Characterization of γδT cells in lung of Plasmodium yoelii-infected C57BL/6 mice

Background Malaria has high morbidity and mortality rates in some parts of tropical and subtropical countries. Besides respiratory and metabolic function, lung plays a role in immune system. gamma delta T cells have multiple functions in producing cytokines and chemokines, regulating the immune response by interacting with other cells. It remains unclear about the role of gamma delta T cells in the lung of mice infected by malaria parasites. Methods Flow cytometry (FCM) was used to evaluate the frequency of gamma delta T cells and the effects of gamma delta T cells on the phenotype and function of B and T cells in Plasmodium yoelii-infected wild-type (WT) or gamma delta TCR knockout (gamma delta T KO) mice. Haematoxylin-eosin (HE) staining was used to observe the pathological changes in the lungs. Results The percentage and absolute number of gamma delta T cells in the lung increased after Plasmodium infection (p < 0.01). More gamma delta T cells were expressing CD80, CD11b, or PD-1 post-infection (p < 0.05), while less gamma delta T cells were expressing CD34, CD62L, and CD127 post-infection (p < 0.05). The percentages of IL-4(+), IL-5(+), IL-6(+), IL-21(+), IL-1 alpha(+), and IL-17(+) gamma delta T cells were increased (p < 0.05), but the percentage of IFN-gamma-expressing gamma delta T cells decreased (p < 0.05) post-infection. The pathological changes in the lungs of the infected gamma delta T KO mice were not obvious compared with the infected WT mice. The proportion of CD3(+) cells and absolute numbers of CD3(+) cells, CD3(+) CD4(+) cells, CD3(+) CD8(+) cells decreased in gamma delta T KO infected mice (p < 0.05). gamma delta T KO infected mice exhibited no significant difference in the surface molecular expression of T cells compared with the WT infected mice (p > 0.05). While, the percentage of IFN-gamma-expressing CD3(+) and CD3(+) CD8(+) cells increased in gamma delta T KO infected mice (p < 0.05). There was no significant difference in the absolute numbers of the total, CD69(+), ICOS+, and CD80(+) B cells between the WT infected and gamma delta T KO infected mice (p > 0.05). Conclusions The content, phenotype, and function of gamma delta T cells in the lung of C57BL/6 mice were changed after Plasmodium infection. gamma delta T cells contribute to T cell immune response in the progress of Plasmodium infection.

Automated summary

This study found an increase in gamma delta T cells in the lungs of mice infected with Plasmodium, affecting the phenotype and function of other cells. Gamma delta T cells contribute significantly to the T cell immune response during Plasmodium infection.