Vitamin B-12-deficiency affects immunoglobulin production and cytokine levels in mice

To clarify the role of B-12 in the immunological function, serum C3, IgM, I gG, IgE contents, splenocytes expression of CD4, CD8, and CD4 positive intr acellular IFN-gamma and IL-4 were examined in B-12-deficient mice, and the effect of the administration of CH3-B-12 was also studied. Serum C3, IgM an d IgG contents were lower in B-12-deficient mice than in the control mice. On the other hand, serum IgE content was sinificantly higher in B-12-defici ent mice, and the value in CH3-B-12 administered mice, administered CH3-B-1 2 to B-12-deficient mice for 48 h before the end of feeding period, showed a tendency to recovery. CD4(+)CD8(-) cells and CD4(+)CD8(-)/CD4(-)CD8(+) ra tio in splenocytes were significantly higher in B-12-deficient mice than in control mice. CD4(+)IFN-gamma (+) cells was significantly lower in B-12-de ficient mice than in control mice, and CD4(+)IL-4(+) was significantly high er in B-12-deficient mice than in control mice. These results suggest that B-12-deficiency causes CD4(+)CD8(-)T cells shift from the T helper type 1 t o the T helper type 2, which participate in the IgE production and elevates CD4(+)CD8(-)/CD4(-)CD8(+) ratio. Thus, B-12 plays a role in maintaining th e immune function in mice.