 A similar pattern of dietary protein effect in (CBA/N x DBA/2J) F1 mice carrying the xid defect was observed following challenge with sheep red blood cells (SRBC).An even greater enhancing effect of dietary L was noted in normal (DBA/2J x CBA/N) F1 mice after immunization with SRBC, but in contrast, the normal large-scale production of B lymphocytes in mouse bone marrow was independent of the type of dietary protein.Dietary protein type did not affect blood level of minerals and trace metals.