Antibody formation in experimental immunizations with Candida albicans ribosomal fractions

Sera of mice immunized with ribosomal fractions of Candida albicans showed the presence of anti-C. albicans antibodies, detected by the gel-immunodiffusion, agglutination and immune adherence tests. Candida infections are among the most prevalent opportunistic yeast infections, attacking debilitated individuals, and against which there is no effective prophylactic treatment currently available (1, 2, 3, 4, 5). In view of the succes reported in experimental immunizations with ribosomal fractions from various bacteria and some fungi, as summarized by Youmans and Tewari (7, 8), a similar approach for immunization in experimental candidiasis appears reasonable. The present work describes preliminary results on circulating antibodies elicited in the course of immunizations with ribosomal fractions of Candida albicans. Ribosomal preparations were obtained from mechanically disrupted cell-pellets of C. albicans by differential centrifugation and purification in a 15% sucrose and 5% ammonium sulfate solution (in sodium-magnesium-Tris buffer), using a modification of the procedure described by Rubin (6). Concentration of ribosomal-RNA was determined by the absorbance at 260 nm; ribosomal-protein concentration by the Lowry reaction; and purity of the ribosomal preparation checked by the ratio of absorbance at 260 nm to 280, and at 260 to 235 nm. Mice (ICR strain) were immunized with these ribosomal preparations in amounts of 50-100 μg ribosomalprotein/mouse, by 2-3 subcutaneous inoculations with Frend's adjuvant, with a 10-21 day interval between the inoculations.