Remote-site stimulation of influenza antibodies in monkeys following intestinal stimulation

Antibodies in nasal secretions and saliva were stimulated in 10 monkeys (Macacus rhesus) which had been immunized orally with a killed influenza vaccine. Prior to immunization, monkeys had no detectable antibody to influenza virus hemagglutinin or neuraminidase in sera or secretions. Oral immunization (6 times within 12 days, total of 0.6 mg hemagglutinin (HA) and 240 neuraminidase units) using intraesophageal intubation induced secretory antibodies to both antigens, but no serum antibody. Six and 8 monkeys reacted with HA-antibodies in nasal secretions and saliva, respectively, whereas neuraminidase antibodies occurred in nasal secretions of all 10 and in the saliva of 9 animals. The results support the concept of a common mucosal immune system in monkeys.