Strain- and sex-linked effects of dietary polyunsaturated fatty acids on tumor growth and immune functions in mice.

In the present paper, we studied the influence of different levels of dietary polyunsaturated fatty acids (PUFA) on the immune system and tumor growth in young mice. Female BALB/c mice fed a PUFA-rich diet display an enhanced body growth, proliferative response to mitogens in vitro, and rate of growth of a spontaneous transplantable adenocarcinoma as compared to PUFA-poor diet-fed females. Such effects are, however, limited by sex and strain background genes located outside the H-2 complex. In effect, the influence of dietary PUFA content is evident in female but not in male BALB/c mice. Moreover, in female DBA/2 mice with the same haplotype (H-2d) of the major histocompatibility complex as that of BALB/c mice, low dietary PUFA determines a reduced tumor growth only, but it does not affect body growth and proliferative response to mitogens in vitro.