The effect of pregnancy on lymph node weight in the mouse.

Lumbar and renal lymph nodes, inguinal lymph nodes and spleen weights were recorded during pregnancy in mice after mating with males of the same (syngeneic) or a different (allogeneic) strain. The weights of these nodes increased during pregnancy. Spleen weights increased up to the fifteenth day of pregnancy and then decreased in weight. There was no consistent correlation of any of these measurements with the extent of the antigenic dissimilarity between mother and conceptus.