Sex-dependent association between immune function and paw preference in two substrains of C3H mice

Asymmetry in brain modulation of the immune system has been previously described in mice. Paw preference is known to be associated with immune reactivity but the respective roles of sex and genetic background in this association remain to be elucidated. In this work, male and female mice of the C3H/He and C3H/OuJIco substrains were selected as right- and left-handers. Mitogen-induced lymphoproliferation and natural killer cell activity were then tested. Left-handed female mice of both C3H substrains exhibited higher mitogenesis than right-handers but no association between paw preference and NK cell activity was found in females. Conversely, in males of both substrains, right-handers showed enhanced NK cell activity compared to left-handers but no association between paw preference and mitogenesis was observed in males. Only small differences in the strength, but not in the direction, of the association between paw preference and immune functions were observed between the two C3H substrains. These results show that the association between paw preference and immune reactivity in mice varies according to the immune parameters tested and is a sex-dependent phenomenon in which the genetic background may be involved.