Studies on the surface component of Trypanosoma cruzi amastigotes: determination of the specific antigen and characterization by enzyme treatment and electronmicroscopy.

A specific antigen to amastigotes of Trypanosoma cruzi was found by immunodiffusion. It was one of the predominant antigens against anti-amastigote serum and also against infected rabbit serum. This specific antigen was mainly eluted in the first peak from a Sephadex G-200 column and moved slowly on immunoelectrophoresis. It was shown to be present on the surface of amastigotes using antiserum to the specific precipitin line between the first fraction of amastigote antigen from the Sephadex G-200 column and the anti-amastigote serum. The surface component of amastigotes was found to be rich in carbohydrate by histochemical electronmicroscopy. The component was also shown to be susceptible to pronase and hyaluronidase, but resistant to trypsin, chondroitinase ABC and neuraminidase, by investigating the sensitivity to the lytic effect of fresh serum from unimmunized rabbits after enzyme treatment. The relation between the specific antigen and the surface component was discussed.