Efficacy of the Candida Precipitin Test: Verification with a Protoplast Antigen Preparation

Cytoplasmic antigens, prepared by sonication of Candida albicans and lysed C. albicans protoplasts, were studied for the presence of surface cell wall antigens. Rabbit antisera were compared by immunodiffusion and immunoelectrophoresis against the two antigen preparations and showed lines of identity and similar electrophoretic patterns. Rabbits immunized with the sonicate preparation failed to demonstrate a rise in agglutination titer to 0.4% formalized whole cells, and precipitin lines were unaffected by adsorption of the antisera with either whole cells or an alkali extract of the Candida cell wall. The two preparations reacted equally well when tested with clinical sera. This study demonstrates the lack of superficial cell wall antigens in the sonicate antigen preparation as detected by routine serologic procedures.