Antigenic analysis of purified surface antigens of filarial nematode Setaria digitata.

The surface antigens of S. digitata were isolated by treatment with Triton X-100. In non SDS-PAGE the surface antigen preparation resolved into more than 6 protein bands. Electroelution of gel slices corresponding to the protein bands with relative mobilities 0.09, 0.32, 0.41, 0.53, 0.61 and 0.76 gave 6 purified surface antigen fractions (SAF). Analysis of SAFs by SDS-PAGE showed that the proteins with molecular weights 17, 29 and 36 KD were the three major polypeptides and different combination of these gave rise to the 6 native surface proteins. The 29 KD protein existed as a monomer and as cross-linked with the 17 and 36 KD proteins. All surface antigen fractions showed antigenicity, where as 29 KD protein remained as a high avidity surface antigen.