Abstract

Background:Microsporidia are a group of obligated intracellular fungus pathogens. Monocytes and the derivative macrophages are among the most important players in host immunity. The invasion of microsporidia may significantly affect the monocytes maturation and extravasation processes.Methods:We utilized a previously established microsporidia infection murine model to investigate the influences of microsporidiaEncephalitozoon hellem(E. hellem) infection on monocyte maturation, releasing into the circulation and extravasation to the inflammation site. Flow cytometry and qPCR analysis were used to compare the monocytes and derivative macrophages isolated from bone marrow, peripheral blood and tissues ofE. hellem-infected and control mice.Results:The results showed that the pro-inflammatory group of CD11b+Ly-6C+monocytes are promoted inE. hellem-infected mice. Interestingly, the percentage of Ly-6C+monocytes fromE. hellem-infected mice are significantly lower in peripheral blood while significantly higher in the inflamed small intestine, together with up-regulated ratio of F4/80 macrophage in small intestine as well.Conclusions:Our findings demonstrated thatE. helleminfection leads to promoted monocytes maturation in bone marrow, up-regulation of extravasation from peripheral blood to inflammation site and maturation into macrophages. Our study is the first systematic analysis of monocytes maturation and trafficking during microsporidia infection, and will provide better understanding of the pathogen–host interactions.Keywords:Encephalitozoon hellem;monocytes;extravasation;peripheral blood;bone marrow