Postnatal changes in the blood of Japanese monkeys (Macaca fuscata): I. Immunoglobulins Ig G, Ig M and Ig A

The levels of immunoglobulin Ig G, Ig M and Ig A in the plasma of Japanese monkeys (Macaca fuscata) from birth to 180 days of age were examined. The level of Ig G reached a minimum at 50 to 80 days of age, when the neonates weighed 600–800 g. Anti streptolysin O antibody decreased from birth with age and was not detected from day 80 to 150. The level of Ig M showed a temporary peak at 20–30 days of age and increased again from 60–80 days. The concentration of Ig A increased gradually to reach 20% of the adult level at day 180.