CD4 and infection: Natural CD25+FoxP3+ TREG cells responsible for suppressing immune response in infection site.CD25-FoxP3-IL-10 producing TREG cells prevent sterile cure and delay healing.CCR5-dependent homing of naturally occurring CD4+CD25+ TREG cells.The role of IL-10 in the persistence of L. major in the skin after healing.Both CD4+CD25+FoxP3+ and CD25-Foxp3- (Tr1) TREG cells as the source of IL-10 production in L. infantum infection.