Effect of vitamin B12 on the complement system

Effect of vitamin B12 on the complement system was investigated in vitro and in vivo. Vitamin B12 was found to reduced both the classical and alternative pathway activity of the complement in vitro. And vitamin B12 was also found to increase serum complement level in guinea pig, measured by hemolytic assay using sensitized sheep erythrocytes (EA) for the classical pathway activity and unsensitized rabbit erythrocytes (RaE) for the alternative pathway activity. And assay of complement components revealed a significant increase in C3 and C4.These evidences suggested that vitamin B12 might potentiate immune response of the host by elevating serum complement level, in additino to activate the complement system.