Abstract
Five kinds of thermo-labile antigens (TLA a, TLA b, TLA c, TLA d and TLA e) of yeast cell surface were isolated. Each TLA was homogeneous on polyacrylamide gel electrophoresis. The molecular weights of TLA a, TLA b, TLA c, TLA d and TLA e were 68, 000, 86, 000, 68, 000, 170, 000 and 82, 000, respectively, as estimated by gel filtration on Sephadex G-200. When gel electrophoresis was performed in 0.1% sodium dodecyl sulfate (SDS), TLA a, TLA b, TLA c and TLA e gave a single band of molecular weight at about 62, 000, 38, 000, 33, 000 or 79, 000 in each test, whereas TLA d gave two bands of molecular weights at about 81, 000 and 40, 000. Among the five kinds of antigens, only TLA e contained 9.7% sugar, the other antigens containing no sugar moiety. TLA a, TLA c, TLA d and TLA e did not give a precipitin line against anti-TLA antisera when heated at 70°C for 10 min, whereas TLA b lost antigenicity by heating at 90°C. the isoelectric points for the five kinds of antigens were at pH 6.4 (TLA a), pH 6.1 (TLA b), pH 5.2 (TLA c), pH 4.7 (TLA d) and pH 4.0 (TLA e). All antisera specific to each TLA agglutinated fresh yeast cells, suggesting that these five kinds of antigens are located on the cell surface.
