PASSAGE OF IMMUNOGLOBULINS FROM PLASMA TO ORAL CAVITY IN RHESUS-MONKEYS

Abstract

The passage of immunoglobulin [Ig] from plasma to the oral cavity was studied in rhesus monkeys. IgG, IgA and IgM were purified from pooled rhesus monkey serum, radiolabeled with 125I and injected i.v. into 12 monkeys. Sequential samples of oral fluids were taken over a 24 h period and were assayed for radioactivity. Radioactivity could be detected in crevicular fluid washings after 0.5 h in monkeys injected with IgG and IgA, and after 2 h in monkeys given IgM. Maximal levels were found after 4 h with each Ig. Radioactivity in parotid and mixed saliva could be detected in all animals after 30 min, reaching a maximum level after 4 h. Ultracentrifugation on sucrose density gradients revealed that most of the radioactivity in crevicular fluid washings was in the 7S zone in the animals given IgG and IgA, and in a 19S zone in animals given IgM. The radioactivity in parotid saliva did not represent intact Ig molecules, since all the activity was present in zones of low MW in animals given IgG, IgA or IgM. In mixed saliva a small amount of radioactivity was found in the Ig zones. Apparently intact molecules of IgG, IgA and IgM can pass from plasma to the oral cavity via crevicular fluid, and could contribute to oral defence mechanisms particularly in the crevicular domain. The volume of crevicular fluid in the approximal space of deciduous molars of rhesus monkeys was approximately 0.3 .mu.l.