Circulating Antibodies in Vitamin—Deficiency States. Pteroylglutamic Acid,Niacin—Tryptophan,Vitamins B 12,A,and D Deficiencies. ∗

Summary

1. Hemagglutinin production in response to inoculation with human erythrocytes has been investigated in pteroylglutamic acid, niacin—tryptophan, vit. B₁₂, vit. A. vit. D-deficient rats and their respective controls. 2. Severe impairment of antibody response was observed in the pteroylglutamic acid—deficient rats. Moderate impairment was demonstrated in vit. A and niacin—tryptophan deficiencies. Vit. B₁₂ and vit. D deficiencies had no effect on antibody formation. 3. A rough classification of the effect of 10 deficiency states upon antibody production is presented.