Specific antibodies in mouse milk after ovalbumin ingestion

C57B1/6J mice received ovalbumin (Ova) orally, 20 mg/day, from day of parturition for 3, 5, 7, 10 or 15 days. Anti-Ova antibodies were titrated in plasma and milk by passive hemagglutination, and Ova-specific plaque-forming cells (PFC) were counted in the spleen and mesenteric lymph nodes. Anti-Ova antibodies in milk and antibody-secreting cells in mesenteric lymph nodes and spleen were detected on day 3, increased on day 5 and peaked on day 10. In contrast, anti-Ova antibodies in serum and PFC in spleen were low on day 7 and decreased on days 10 to 15. Although the oral administration of this antigen has been used to induce oral tolerance or secretory immune responses in the mouse, the present study demonstrates that the repeated ingestion of ovalbumin results in the development of circulating and secretory antibodies.