Microbial ribosomal vaccines.

Ribosomal vaccines have been prepared from several different bacterial, fungal, and protozoan microorganisms. Most of these preparations offer a higher degree of protection than do vaccines made from the homologous whole cells, but the mode of protection is controversial. All of the reported ribosomal vaccines are contaminated with cell surface determinants. Antisera raised to ribosomal preparations are directed to innate ribosomal components as well as to surface antigens. Several hypotheses exist for the reported protection from disease: the cell surface contaminants serve as the protective moieties; ribosomes act as potent adjuvants for contaminating cell surface determinants; ribosomes innately contain antigenic determinants that cross-react with cell surface antigens; recently translated cell surface polypeptides are still attached to the ribosomal RNA in the ribosomes; ribosomes migrate from the cytoplasm of the microbe to the periphery of the cell, and ribosomal antigens are exposed on the cell surface; or ribosomes contain messenger RNA and produce microbial cell surface polypeptides in immunized individuals. A short description of the biochemical, biophysical, and structural characteristics of prokaryotic and eukaryotic ribosomes is presented, followed by a discussion of the ability of various ribosomal vaccines to protect against infectious agents.