The role of RCA-binding sites in the adhesion of trypanosoma cruzi to heart muscle cells, as revealed by electron spectroscopic imaging.

The involvement of host-cell surface membrane components during T. cruzi-heart muscle cell (HMC) interaction was investigated. We used the lectin RCA I (Ricinus communis), which binds to residues of D-galactose, conjugated with ferritin as a tool to reveal the role played by lectin-binding sites during adhesion of T. cruzi to HMC. With electron spectroscopic imaging (ESI) it was possible to observe a concentration of RCA I-ferritin particles on the surface membrane of HMC at the site of parasite attachment. This suggested that migration of galactosyl residues was occurring during the cellular recognition process, particularly since these particles were absent in the immediate vicinity of the attachment site, while being present in other regions of HMC membrane not related to the attachment sites. No region of the parasite's cell body was observed to have preferential status for the purposes of adhesion to HMC.