The effect of reinoculation with trypomastigotes on the level of protective antibodies in mice chronically infected with T. cruzi
Pereira, M.E.; Krettli, A.U.
Brazilian Journal of Medical and Biological Research 23(3-4): 283-292
1990
ISSN/ISBN: 0100-879X PMID: 2128821 Document Number: 364667
The levels of specific antibodies were determined in sera from mice chronically infected with Trypanosoma cruzi using indirect immunofluorescence, complement-mediated lysis, and neutralization of bloodstream trypomastigote (Try) infectivity upon their incubation with the test sera in vitro and passive transfer of immune sera. The sera were obtained at different times after T. cruzi inoculation performed one to 5 times using live Y or CL bloodstream Try. High levels of protective and nonprotective antibodies were detected from week 4, the first interval studied, onward, regardless of number of inoculations and time of infection. Sera from CL-infected mice had lower antibody titres at week 4 and the ability of whole sera or semipurified IgG to neutralize the infectivity of bloodstream Try was lower at this time. All other sera obtained during the chronic phase were strongly effective in decreasing parasite infectivity as measured by lower parasitaemia and mortality of mice inoculated with the serum-treated Y strain bloodstream Try.