title: Mast cell degranulation contributes to susceptibility to Leishmania major.
abstract: Leishmaniasis causes high morbidity and mortality in tropical and subtropical areas. Mast cells can be activated by Leishmania or Leishmania products in vitro and in vivo. Several innate immunity mediators, including some released by mast cells, play roles in the outcome of the disease. In this study, we examined whether pharmacological inactivation of mast cells before infection with L. major interferes with the progressive disease in BALB/c mice. The results show that, when mast cells are degranulated before challenge with L. major, susceptible mice become more resistant to infection, as measured by decrease of lesion size and lower parasite loads. Mast cell degranulation reduced IL-4 production. Moreover, mast cells degranulation enhanced mRNA expression for IFN-gamma, inducible nitric oxide, CCL2 and CCL5 in response to infection. Mast cell degranulation also decreased parasite loads in IL-4 KO animals, indicating that mediators other than IL-4 are involved in susceptibility in vivo. Taken together, our results disclose a role for mast cells in the induction of susceptibility to infection. This work contributes to a better understanding of the role of mast cells in Leishmania infection, and suggests a new field of study for strategies to contain the parasite, restricting its dissemination.
authors.affiliation: Universidade do Extremo Sul Catarinense, Criciúma, SC, Brazil.
authors.forename: P R T
authors.initials: PR
authors.lastname: Romão
authors.forename: H
authors.initials: H
authors.lastname: Da Costa Santiago
authors.forename: C D L
authors.initials: CD
authors.lastname: Ramos
authors.forename: C F E
authors.initials: CF
authors.lastname: De Oliveira
authors.forename: M C
authors.initials: MC
authors.lastname: Monteiro
authors.forename: F
authors.initials: F
authors.lastname: De Queiroz Cunha
authors.forename: L Q
authors.initials: LQ
authors.lastname: Vieira
mesh_terms: D000818:Animals; D015550:Cell Degranulation; D018932:Chemokine CCL2 / Q000096:biosynthesis; D018946:Chemokine CCL5 / Q000096:biosynthesis; D004198:Disease Susceptibility; D005260:Female; D005528:Foot / Q000469:parasitology / Q000473:pathology; D020869:Gene Expression Profiling; D007371:Interferon-gamma / Q000096:biosynthesis; D015847:Interleukin-4 / Q000096:biosynthesis / Q000172:deficiency; D018320:Leishmania major / Q000276:immunology*; D016773:Leishmaniasis, Cutaneous / Q000276:immunology* / Q000473:pathology; D008407:Mast Cells / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009569:Nitric Oxide / Q000096:biosynthesis
chemical_list: C491768:Ccl2 protein, mouse; C503460:Ccl5 protein, mouse; D018932:Chemokine CCL2; D018946:Chemokine CCL5; D015847:Interleukin-4; D009569:Nitric Oxide; D007371:Interferon-gamma