Primary in vitro antibody formation by blood leucocytes of a subhuman primate

Blood leucocytes from humans and two species of marmosets, S. fuscicollis and S. oedipus oedipus, were cultured in vitro with sheep red blood cells. Leucocyte cultures from 16 of 20 S. fuscicollis marmosets produced significant numbers of plaque-forming cells (PFC) as assayed by the Jerne procedure. Under the same conditions, none of 15 S. oedipus oedipus cultures and only 1 of 15 human blood cultures responded. A kinetic study of the response with S. fuscicollis leucocytes revealed peak 19S and 7S PFC to appear on Day 9 of culture. It is suggested that two factors are acting synergistically in the successful development of antibody-forming cells from leucocytes of S. fuscicollis marmosets: (a) the innate immune response capabilities of the blood lymphocytes and (b) the natural hemopoietic chimerism that occurs in this species.