Psychosocial influences on immune responses to HSV-1 infection in BALB/c mice

The effects of differential housing (one or four mice/cage) on T-helper (Th) cell markers of cellular and humoral immune responses were examined. Differentially housed male BALB/cJ mice were infected with herpes simplex virus (HSV)-1 (Patton strain), and in vitro cytokine production [interleukin (IL)-2, IL-4, IL-10, and interferon (IFN)-gamma] by splenocytes and popliteal lymph node cells and serum antibody titers (IgM and IgG) were evaluated. Differential housing of male BALB/c mice influenced the magnitude, but not the kinetics, of some, but not all, immune responses to HSV-1. Splenocytes from individually housed mice produced more IL-2, IFN-gamma, IL-4, and IL-10 than splenocytes from group-housed mice; in popliteal lymph node cells, only IFN-gamma and IL-10 production was influenced by housing. Although the social environment influenced cytokine production, there were no concomitant changes in circulating IgM or IgG antibody titers. These results do not support the hypothesis that dominant Th cell responses are the primary targets of this psychosocial manipulation, or that a reciprocal relationship exists between Th1 and Th2 cell-derived cytokines.