IL17A and infection: Furthermore, other studies have reported that γδ T cells are the major producers of IL-17 in herpes simplex virus [40] and Mycobacterium tuberculosis [52] infection, and in Schistosoma japonicum infection, IL-17 is mainly produced by NKT cells [55], suggesting that pathogens might differently affect the phenotype and distribution of IL-17A-producing T cells that act as the main source of intracellular IL-17A cytokine.