1998 Volume 4 Issue 2 Pages 125-129
The effects of aged fermented bovine milk produced by a mixture of various lactic acid bacteria and a yeast, or a mixture of the lactic acid bacterium, Bifidobacterium longum, and a yeast on the proliferation activities of human carcinoma cells (DLD-1, MKN-1, and HL-60 cell lines) and human normal fibroblast cells (Fb) were investigated. Nonfermented bovine milk suppressed the proliferation activity in various degrees depending on the cell lines tested, suggesting that bovine milk may contain a component regulating in vivo proliferation of certain cells. The fermented milk produced by a mixture of various lactic acid bacteria and a yeast selectively reduced the proliferation activity of DLD-1 and MKN-1 cells. In contrast, the fermented milk produced by a mixture of B. longum and a yeast was selectively toxic to HL-60 cells, and cell proliferation activity was completely lost. Analysis of this cytotoxicity was revealed to be due to the induction of apoptosis which was demonstrated by the formation of apoptotic bodies and the fragmentation of DNA in treated cells. These findings strongly suggest that the cytotoxic factors affecting the viability of transformed and nontransformed cells are present in latent form in bovine milk, and these factors could be produced from milk by digestion using microbial enzymes.