Immunological properties of a high molecular weight component from yeast cell autolysate in dogs and evaluation of its potential role in human dextran reactions

A high molecular weight component (HMC) of autolysate from Saccharomyces cerevisiae yeast cells was prepared. HMC was found to be immunogenic in dogs, inducing hemagglutinating antibody formation. Upon HMC challenge of immunized dogs, systemic anaphylactoid reactions were observed in 4/5 animals. The most prominent symptom was decreased cardiac output. Decrease in mean arterial pressure and increase in pulmonary arterial pressure were also observed. Consumption of total serum complement activity amounted to 22% of initial values. HMC also exhibited mitogenic activity in lymphocyte cultures from nonimmunized and immunized dogs. Since yeast autolysate is used as nitrogen source for Leucon- ostoc mesenteroides in the production of clinical B 512 dextran it is a theoretically possible trace contaminant of such solutions. Therefore, dogs hyperimmunized with HMC were also challenged with clinical dextran. No anaphylactoid signs were observed. These data suggest a negligible causal role of macromolecular contaminants derived from yeast cell autolysate in rare human anaphylactoid reactions following infusion of clinical dextran.