REACTIVITY OF TRYPANOSOMA-CRUZI STRAINS WITH PEANUT AGGLUTININ (PNA) CORRELATES WITH NUMBER OF IN-VITRO INFECTED HOST-CELLS

Reactivities of 4 lectins with intact trypomastigote forms derived fro m 8 different Trypanosoma cruzi strains were compared with their capac ity to infect in vitro cultured LLC-MK(2) cells. A sensitive and repro ducible titration method for lectin binding sites (ELLA: Enzyme Linked Lectin Assay) was employed, in which reactivities were scored through optical densities in an ELISA reader. Tissue culture trypomastigotes from the strains Y, CL, SC4, SC24, SC25, SC28, SC32 and SC33 were inve stigated for expression of different cell surface carbohydrate residue s using Concanavalin A (ConA), Peanut agglutinin (PNA), Soybean agglut inin (SEA) and Wheat germ agglutinin (WGA) conjugated to peroxidase. T he reactivity of the strains to PNA lectin was SC28 > SC32 > SC33 > SC 25 > SC24 > Y > CL > SC4. The optical density values obtained were hig hly correlated (r(2)=0.986, p<10(-4)) with the number of parasitized L LC-MK(2) cells 24 hours after infection by trypomastigotes from each c orresponding strain. We concluded that galactose and N-acetyl-D-galact osamine residues that are present on the surface of trypomastigotes ar e important in host-cell recognition.