Immunogenicity of Trypanosoma cruzi strains determined by neutralization test.

ABSTRACT

Trypomastigotes of the CA-I strain of Trypanosoma cruzi, which is practically non-lethal for mice, exhibited adhered antibodies when harvested 25-28 days pi and handled at 4 degrees C, whereas at 37 degrees C they became negative within 10-15 min. Mice injected with these tryp pre-incubated with anti-RA rabbit serum (shown to contained neutralizing antibodies against the homologous strain) developed a significantly lower parasitemia than controls while those pre-incubated with anti-CA-I serum showed only a delay in the parasitemia pattern. Neutralizing activity was undetectable in anti-CA-I rabbit and mouse sera when the test was performed under standard conditions against RA-tryp. On the other hand, neutralizing antibodies were demonstrated in few anti-CA-I mouse serum samples against RA strain when the test was performed increasing the sensitivity in order to reach no more than 75