SDS-PAGE profiles of the proteins from six Pythium insidiosum strains in this study. The gels were stained with Coomassie brilliant blue. Lanes: 1, MTPI-19; 2, MTPI-04; 3, MTPI-12; 4, MTPI-14; 5, MTPI-21; and 6, MTPI-24. Asterisk, the ∼74-kDa-molecular-mass antigen, solid arrowhead, one of the antigens in strain MTPI-14 prominently expressed in vitro; arrow, putative location of the immunodominant ∼28-kDa-molecular-mass antigen found on almost all WB membranes (Fig. 2 to 4). Note that the 28-kDa immunodominant antigen is faintly expressed on the SDS-polyacrylamide gels. Lane M, molecular mass marker (the numbers on the left are in kilodaltons).