Effect of β-Casein (1-28) on Proliferative Responses and Secretory Functions of Human Immunocompetent Cell Lines

The effect of bovine beta-casein (1-28) purified from commercial casein phosphopeptide preparations on human T, B, and monocyte cell lines was evaluated. Beta-casein (1-28) enhanced the proliferation of the following: T cell lines HUT-78, Jurkat Clone E6-1, and MOLT-4; B cell lines BALL, KHM-1B, and U266B1; and monocyte cell lines U937 and HL-60. Moreover, beta-casein (1-28) stimulated IgA production by KHM-1B over 96 h of culture. Semiquantitative reverse transcriptional-polymerase chain reaction analysis indicated that beta-casein (1-28) enhanced mRNA expression of interleukin (IL)-6 in U266B1 and KHM-1B. These results suggest that beta-casein (1-28) exerts a mitogenic effect on human T, B, and monocyte cells, and an IgA-enhancing effect on B cells.