Postnatal Changes of IgG and IgM Levels in Squirrel Monkeys (Saimiri sciureus)

A two-site sandwich immunoradiometric assay of squirrel monkey (Saimiri sciureus) IgM using monoclonal antibodies

Nine hybrid clones secreting antibodies to squirrel monkey (Saimiri sciureus) IgM were produced and two of these (1F1G5 and 5H11B3) were selected for further studies. These non-precipitating monoclonal antibodies reacted with two distinct repetitive antigenic determinants, probably of the conformational type, only present on the native or SDS-denatured IgM molecule. Reduction of the pentamer with 2-mercaptoethanol led to complete destruction of the corresponding epitopes. 1F1G5 antibodies from ascitic fluids were used in the purification of monkey IgM by affinity chromatography. The characteristics of 1F1G5 and 5H11B3 MAbs permitted the development of a solid-phase two-site immunoradiometric assay for the measurement of IgM levels in serum specimens taken from healthy animal donors of both sexes.

Effects of age, sex, and psychological disturbance on immunoglobulin levels in the squirrel monkey

The following research assessed the influence of developmental, hormonal, and psychological factors on immunoglobulin and complement protein levels in the squirrel monkey. A cross-sectional life span study established that the developmental pattern of immunoglobulins and complement proteins was similar to that observed in humans. IgG and IgM levels rose progressively with age, while the complement system was mature at birth. In contrast to humans, this species showed a significant sex difference in IgG levels, with higher levels in males during both infancy and adulthood. Males also showed a greater antibody response to viral challenge than did females, and evaluation of gonadectomized subjects suggested that the sex difference in antibody production was testosterone-dependent. The effect of acute and sustained psychological disturbance on IgG levels was also evaluated in infant monkeys. Repeated, brief separations from the mother did not alter IgG levels, but IgG levels were suppressed after a 7-day removal from the mother. Therefore, despite the general view that immunoglobulin levels are relatively stable, these studies have established that immunoglobulin levels can be strongly influenced by hormonal and experiential factors in the squirrel monkey.