title: Prolactin: does it exert an up-modulation of the immune response in Trypanosoma cruzi-infected rats?
abstract: During the course of infection by Trypanosoma cruzi, the host immune system is involved in distinct, complex interactions with the endocrine system, and prolactin (PRL) is one of several hormones involved in immunoregulation. Although intensive studies attempting to understand the mechanisms that underlie Chagas' disease have been undertaken, there are still some pieces missing from this complex puzzle. Because data are scarce concerning the role of PRL involvement in Chagas' disease and taking into account the existence of crosstalk between neuroendocrine hormones and the immune system, the current study evaluates a possible up-regulation of the cellular immune response triggered by PRL in T. cruzi-infected rats and the role of PRL in reversing immunosuppression caused by the parasitic infection. The data shown herein demonstrate that PRL induces the proliferation of T lymphocytes, coupled with an activation of macrophages and the production of nitric oxide (NO), leading to a reduction in the number of blood trypomastigotes during the peak of parasitemia. During the acute phase of T. cruzi infection, an enhancement of both CD3+CD4+ and CD3+CD8+ T cell populations were observed in infected groups, with the highest numbers of these T cell subsets found in the infected group treated with PRL. Because NO is a signaling molecule involved in a number of cellular interactions with components of the immune system and the neuroendocrine system, PRL can be considered an alternative hormone able to up-regulate the host's immune system, consequently lowering the pathological effects of a T. cruzi infection.
authors.affiliation: Department of Clinical Analysis, Toxicology and Bromatology, College of Pharmaceutical Sciences of Ribeirão Preto (FCFRP), University of São Paulo, Ribeirão Preto, São Paulo, Av. do Café s/n, 14040-903 Ribeirão Preto, SP, Brazil.
authors.forename: Marina Del Vecchio
authors.initials: Mdel V
authors.lastname: Filipin
authors.forename: Vânia
authors.initials: V
authors.lastname: Brazão
authors.forename: Fabricia Helena
authors.initials: FH
authors.lastname: Santello
authors.forename: Leony Cristina
authors.initials: LC
authors.lastname: Caetano
authors.forename: Míriam Paula Alonso
authors.initials: MP
authors.lastname: Toldo
authors.forename: José Clóvis
authors.initials: JC
authors.lastname: do Prado
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D014355:Chagas Disease / Q000276:immunology* / Q000469:parasitology; D003208:Concanavalin A; D005434:Flow Cytometry; D007113:Immunity, Innate / Q000276:immunology*; D008070:Lipopolysaccharides; D017737:Macrophages, Peritoneal / Q000502:physiology; D008297:Male; D009569:Nitric Oxide; D018512:Parasitemia; D011388:Prolactin / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D016176:T-Lymphocyte Subsets / Q000502:physiology; D060168:Thymocytes / Q000502:physiology; D014349:Trypanosoma cruzi; D015854:Up-Regulation / Q000502:physiology*
chemical_list: D008070:Lipopolysaccharides; D003208:Concanavalin A; D009569:Nitric Oxide; D011388:Prolactin