Evaluation of C3b/C3bi opsonization and chemiluminescence with selected yeasts and bacteria using sera of different...

C3 fragment opsonization and chemiluminescence were assessed using two yeasts (Saccharomyces cerevisiae and Candida albicans) and two strains of bacteria (Staphylococcus aureus and Escherichia coli) following incubation with sera previously shown to be either efficient or poor in the opsonization of baker's yeast. Sera with poor function consistently fixed lower levels of C3 fragments and generated less chemiluminescence with all four organisms than sera with normal function. The differences were most marked with the two yeasts. We conclude that sera with normal complement function but manifesting a relatively common defect in the opsonization of baker's yeast have a general opsonic defect.