INFECTION AND IMMIUNITY, May 1978, p. 567-569 0019-9567/78/0020-0567$02.00/0 Copyright © 1978 American Society for Microbiology
Vol. 20, No..2
Printed in U.S.A.
NOTES Induction of Capping in Blood-Stage Trypomastigotes of Trypanosoma cruzi by Human Anti-Trypanosoma cruzi Antibodies GABRIEL A. SCHMUNIS,'* ANA SZARFMAN,' TOMAZ LANGEMBACH,2 AND WANDERLEY DE SOUZA' Department of Immunology' and Department of General Microbiology,2 Institute ofMicrobiology and Institute of Biophysics,:3 Federal University of Rio de Janeiro, Rio de Janeiro, Brazil Received for publication 12 October 1977
The effect of human-specific antibody on surface membrane antigens of trypomastigotes of Trypanosoma cruzi was studied in vitro by using immunofluorescence methods. Immune sera induced aggregation of surface antigens in trypomastigotes to form polar cell caps. Human infections by Trypanosoma cruzi are widespread in Central and South America (13). The infection usually occurs at an early age, and unless infected people are properly treated during the acute phase, they may harbor the parasite throughout their lives. Although humoral antibodies have been reported to protect against blood trypomastigotes (1, 7-9), at least 50% of chronically infected individuals have parasitemias detectable by xenodiagnosis (10). Thus, it appears that at least part of the T. cruzi population in blood is resistant to the effect of antibodies. It has recently been suggested that antibody-induced capping of membrane antigens in leishmania and toxoplasma could represent a resistance mechanism against host antibody (2-5). It is therefore of interest to determine whether this phenomenon also occurs in T. cruzi blood trypomastigotes incubated in the presence of human-specific antibody. Anti-T. cruzi antisera were obtained from two persons chronically infected with T. cruzi. Their sera had titers as determined by indirect immunofluorescence (1:128 and 1:256), indirect hemagglutination (1:32 and 1:128), and complement fixation (1:32 and 1:32) tests, and parasitemias were positive by xenodiagnosis. Serum samples from two persons with negative serology (indirect immunofluorescence and indirect hemagglutination c1:4 and complement fixation
Vol. 20, No..2
Printed in U.S.A.
NOTES Induction of Capping in Blood-Stage Trypomastigotes of Trypanosoma cruzi by Human Anti-Trypanosoma cruzi Antibodies GABRIEL A. SCHMUNIS,'* ANA SZARFMAN,' TOMAZ LANGEMBACH,2 AND WANDERLEY DE SOUZA' Department of Immunology' and Department of General Microbiology,2 Institute ofMicrobiology and Institute of Biophysics,:3 Federal University of Rio de Janeiro, Rio de Janeiro, Brazil Received for publication 12 October 1977
The effect of human-specific antibody on surface membrane antigens of trypomastigotes of Trypanosoma cruzi was studied in vitro by using immunofluorescence methods. Immune sera induced aggregation of surface antigens in trypomastigotes to form polar cell caps. Human infections by Trypanosoma cruzi are widespread in Central and South America (13). The infection usually occurs at an early age, and unless infected people are properly treated during the acute phase, they may harbor the parasite throughout their lives. Although humoral antibodies have been reported to protect against blood trypomastigotes (1, 7-9), at least 50% of chronically infected individuals have parasitemias detectable by xenodiagnosis (10). Thus, it appears that at least part of the T. cruzi population in blood is resistant to the effect of antibodies. It has recently been suggested that antibody-induced capping of membrane antigens in leishmania and toxoplasma could represent a resistance mechanism against host antibody (2-5). It is therefore of interest to determine whether this phenomenon also occurs in T. cruzi blood trypomastigotes incubated in the presence of human-specific antibody. Anti-T. cruzi antisera were obtained from two persons chronically infected with T. cruzi. Their sera had titers as determined by indirect immunofluorescence (1:128 and 1:256), indirect hemagglutination (1:32 and 1:128), and complement fixation (1:32 and 1:32) tests, and parasitemias were positive by xenodiagnosis. Serum samples from two persons with negative serology (indirect immunofluorescence and indirect hemagglutination c1:4 and complement fixation
