Development of immunoglobulin-containing cell populations in intestine, spleen, and mesenteric lymph node of the young pig, as demonstrated by peroxidase-conjugated antiserums.

Peroxidase-conjugated antibody to porcine immunoglobulins A, G, and M were used in a light microscope study of the development of immunoglobulin-containing cells in small intestine, spleen, and mesenteric lymph node of the young pig. Many cells staining for each of the 3 immunoglobulin classes were present in duodenum of 1-week-old-pigs, and the number increased in succeeding weeks. Immunoglobulin M cells outnumbered immunoglobulin A cells in the 1- to 3-week-old pigs, after which immunoglobulin A cells predominated. Immunoglobulin G cells were present in considerable but smaller numbers at all ages. Stained cells in spleen and mesenteric lymph node were not detected until after pigs were 1 week old.