Study of immune cells involved in the antitumor effect of kefir in a murine breast cancer model

A. DE MORENO DE LEBLANC; C. MATAR; E. FARNWORTH; G. PERDIGON

JOURNAL OF DAIRY SCIENCE

AMER DAIRY SCIENCE ASSOC-ADSA

Lugar: Champaign, Illinois; Año: 2007 vol. 90 p. 1920 - 1928

0022-0302

Administration of kefir and a kefir cell-free fraction (KF) to mice injected with breast tumor cells produced, locally in the mammary gland, different profiles of cells secreting cytokines. Here, the immune cell populations in mammary glands affected by the cyclic consumption of kefir or KF for 2 or 7 d were evaluated using a breast tumor model. Apoptosis was also assayed as another mechanism involved in tumor growth delay. The rate development of tumor cells, IgA(+) cells, and CD4+ and CD8+ T lymphocytes was monitored in mammary gland tissues. The number of Bcl-2(+) cells in the mammary gland was compared with the apoptosis observed in the tumor. Two-day cyclical administration of both products delayed tumor growth and increased the number of  IgA(+) cells in the mammary gland. Changes in the balance between CD4+ and CD8+ cells in the mammary gland were observed in mice from the group fed KF cyclically for 2 d, such that the number of CD4+ cells increased when the number of CD8+ cells remained constant. Mice that received 2-d cyclic administration of KF  showed significant increases in the number of apoptotic cells and decreases in Bcl-2(+) cells in the mammary  gland, compared with the tumor control group. The present study allows a better understanding of the  mechanisms (immune and nonimmune) involved in the antitumor effect observed in mice administered kefir or  KF. The importance of nonmicrobial components released during milk fermentation to obtain the beneficial  antitumor effects is also reported.