Abstract
Eleven Pectinatus cerevisiophilus strains of brewery origin were classified serologically by gel diffusion precipitin tests, immunoelectrophoresis, and the fluorescent antibody staining technique. The Pectinatus strains could be assigned immunologically to three different groups. Groups I and III were found to be very closely related, and only some of the antisera used showed differences. The antisera against the strains belonging to group II contained a common group antigen. A strong precipitation band found near the antigen was shown to represent the interaction of the lipopolysaccharide antibody and the respective antigen.