Immunity at the Crossroads of Cellular Metabolism: Navigating T helper Shifts in the Periparturient Period of Dairy Cows 3694

Abstract Description The transition from pregnancy to lactation in dairy cows brings major metabolic and physiological shifts, which lead to an increase in their disease susceptibility and immune dysfunction. The contribution of T helper (CD4+) cells to this altered state during the periparturient period remains poorly understood. This study aimed to evaluate the metabolic and proliferation capacity changes of CD4+ T cells during the periparturient period of dairy cows. Blood samples from multiparous Holstein cows (n = 18) were collected at -28, +3, and +28 days relative to calving. Peripheral blood mononuclear cells were isolated and CD4+ T cells were obtained using magnetic sorting. Cell metabolic function was measured with a Seahorse XF HS mini analyzer in resting and PMA/Ionomycin-activated cells. For proliferation capacity, cells were incubated with Concanavalin A for 72h and tracked using Cell Trace in Flow Cytometry. Data was analyzed in SAS 9.4 using a linear mixed-effect model with repeated measures. Results showed higher rates of glycolysis in CD4+ T cells during the post-partum period (P < 0.01) as well as oxidative phosphorylation capacity (P < 0.05). The proliferation capacity of the cells according to their expansion and division index, was higher at d + 3 than d -28 (P < 0.05). This suggests that CD4+ T cells metabolism as well as their proliferation capacity are affected by the physiological changes that occur after calving, which may impact immune response effectiveness. Funding Sources Dairy Innovation Hub. Topic Categories Veterinary and Comparative Immunology (VET)