title: TGF-beta-associated enhanced susceptibility to leishmaniasis following intramuscular vaccination of mice with Leishmania amazonensis antigens.
abstract: Leishmania amazonensis and Leishmania braziliensis are the main causal agents of anergic diffuse cutaneous leishmaniasis and hyperergic mucosal leishmaniasis in man, respectively. In this work we demonstrate that intramuscular vaccination of BALB/c mice with whole antigens of L. amazonensis (LaAg) but not L. braziliensis (LbAg) results in increased susceptibility to cutaneous leishmaniasis. LaAg vaccination resulted in an increased capacity of the draining lymph nodes to produce IL-10 and TGF-beta during antigen recall responses. In vitro cultivation with LaAg but not LbAg induced increased apoptosis of CD8+ T cells. Following infection with L. amazonensis, LaAg-vaccinated mice produced significantly more TGF-beta and a higher serum IgG1/IgG2a antibody ratio compared with LbAg-vaccinated and non-vaccinated animals. The association of TGF-beta with enhanced susceptibility to infection was confirmed in mice co-vaccinated with LaAg and neutralizing anti-TGF-beta antibodies. Upon parasite challenge, these animals developed much smaller lesion sizes and parasite burdens, comparable with non-vaccinated controls. The disease-promoting effect of LaAg vaccination is not a general event, as in contrast to BALB/c, the disease outcome in C57Bl/6 mice was unaltered. Together, these findings indicate that species-specific components of L. amazonensis activate overt TGF-beta production that predisposes more susceptible individuals to aggravated disease following vaccination.
authors: Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21949-900 Rio de Janeiro, RJ, Brazil.
authors: Roberta Olmo
authors: RO
authors: Pinheiro
authors: Eduardo Fonseca
authors: EF
authors: Pinto
authors: Janaina Ribeiro Correia
authors: JR
authors: Lopes
authors: Herbert Leonel Matos
authors: HL
authors: Guedes
authors: Regina Ferro
authors: RF
authors: Fentanes
authors: Bartira
authors: B
authors: Rossi-Bergmann
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000008:administration & dosage* / Q000276:immunology; D017209:Apoptosis / Q000276:immunology*; D004198:Disease Susceptibility; D007273:Injections, Intramuscular; D007891:Leishmania / Q000276:immunology*; D007896:Leishmaniasis / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D016212:Transforming Growth Factor beta / Q000276:immunology*; D014611:Vaccination
chemical_list: D000953:Antigens, Protozoan; D016212:Transforming Growth Factor beta