Immunoglobulins and measles antibody in sera of newborn cynomolgus monkeys and in milk of their mothers.

The changes in the serum immunoglobulin (Ig) level and in the measles antibody titer were examined with colony-born infant cynomolgus monkeys from 0 day to 26 weeks in age. In addition, their mother-monkey's milk was analyzed for Ig. The decrease in the IgG level after birth was more remarkable in the infants born with high IgG levels than those born with low IgG levels. The IgM level prominently increased for the first 3 weeks after birth in the infants born with low IgG levels, while the increase was not so prominent in those born with high IgG levels. Anti-measles antibody titers decreased linearly with a half-life of 3.4 +/- 0.4 weeks after birth regardless of the titer at birth. A significant amount of IgA, a very small amount of IgM and little IgG were detected in the milk collected just after parturition. Ig of any class was no longer found in the milk collected one to 6 weeks after parturition. These results suggest that the initial level of transplacentally transferred IgG must be one of the important factors influencing the subsequent development of infant monkey's own immunoglobulin synthesis.