Marmoset species variation in the humoral antibody response: in vivo and in vitro studies.

A comparison of the in vivo and in vitro antibody response capabilities of two marmoset species, Saguinus fuscicollis and Saguinus oedipus oedipus, revealed the former to be superior in elaborating humoral antibody. In vivo challenges with Escherichia coli lipopolysaccharide (LPS) and Salmonella typhi flagella consistently yielded higher antibody titres in S. fuscicollis; indeed, with LPS antigen, multiple inoculations of S.o. oedipus marmosets led ultimately to a decrease in antibody formation, in contrast to the anamnestic response of S. fuscicollis. This species differential in immune competence was also suggested in the in vitro stimulation of peripheral blood leucocytes (PBL) and spleen cells with sheep red blood cells (RBC). None of 55 S.o. oedipus PBL cultures and 49 of 89 (55%) S. fuscicollis cultures responded to the test antigen. A similar differential in response to sheep RBC was noted with the spleen cells of each species, although this report contrasts the antibody-forming potential of two marmoset species, a comparison of the immunological response profile of marmosets to those of other laboratory animals challenged with similar antigens suggests these primates may be relatively incompetent. The possible relationship between the haemopoietic chimerism of marmosets and a diminished immune competence is discussed.