Effects of Hen Egg Proteins on Proliferative Responses of Mouse Spleen Lymphocytes

Abstract

Effects of hen egg proteins on proliferative responses of mouse spleen lymphocytes were studied. Ovalbumin inhibited the proliferation of concanavalin A (ConA)-stimulated lymphocytes, while ovomucin enhanced the proliferation stimulated by lipopolysaccharide. Moreover, avidin markedly inhibited both proliferative responses stimulated by ConA and pokeweed mitogen. These results suggest that ovalbumin, avidin and ovomucin might enhance the antibody production at the cell level. Hence, the inhibitory effect of avidin on the ConA-stimulated proliferation was studied in more detail. The inhibitory effect of avidin hardly changed in the presence of biotin or at higher concentrations of ConA. A significant inhibition was observed when avidin was added before or after ConA, simultaneously with ConA, and after pre-incubation with ConA. Avidin bound to ConA-agarose and the bound material was eluted at 0.5 M methyl-α-D-mannopyranoside. The inhibitory activity of avidin reduced significantly by α-mannosidase or pepsin digestion. On the other hand, avidin enhanced ConA-stimulated proliferation of T lymphocyte-enriched fraction. These observations suggest that both carbohydrate and polypeptide portions of avidin are responsible for the inhibition of ConA-stimulated proliferation, and that the inhibition is not only due to direct binding between the mitogen and avidin but also to accessory cell participation.