Erythrocyte binding factors in the sera of the adult lamprey Geotria australis

Abstract

Adults of the Southern Hemisphere lamprey Geotria australis possess three major factors in their sera which bind to erythrocytes in vitro; in addition, an induced factor can also be demonstrated in the sera of animals immunized against human erythrocytes. These factors are a hemagglutinin, a hemolysin and a further binding factor together with a probable antibody. Furthermore, differences in agglutination patterns following immunization were noted between animals of different age groups. Old adults possessed a unique dilution pattern, containing a negative zone which occurred shortly after the initial dilutions, followed by a return to the normal agglutination pattern in the higher dilutions to a titer of 2 18. While the greatest agglutinating activity took place in sera taken from immunized animals, all animals possessed weak, low titer nonspecific direct agglutination together with a strong nonspecific binding activity which was revealed only by the use of an antiserum to lamprey plasma proteins. It is suggested that the interaction of these factors may account, in some measure, for the confusion concerning the nature and magnitude of the immune response in this phylogenetically important group of animals.