Inhibitory Properties of Japanese Quail Ovoinhibitor toward Lymphocyte Proliferations

Abstract

This study evaluated the influence of quail ovoinhibitor at concentrations ranging from 0 to 400μg/ml on proliferative responses and immunoglobulin production of mouse or quail splenocytes stimulated by lipopolysaccharide (LPS), pokeweed mitogen, phytohemagglutinin (PHA) or concanavalin A (ConA). The ovoinhibitor suppressed in a dose-dependent manner all mitogen-induced proliferations of both splenocytes and immunoglobulin production in mouse splenocyte cultures. The inhibitor revealed a cytotoxicity toward mouse and quail splenocytes at concentrations of more than 150μg/ml. The lectins could bind to mouse spleen lymphocytes previously incubated with ovoinhibitor, while ConA directly bound to the protein. The loss pattern of the inhibitory effect of quail ovoinhibitor during heat treatment on LPS- or PHA-induced proliferation of mouse splenocytes was very similar to that on the proteolytic activity of trypsin. Mouse spleen lymphocytes produced enzymatic activities toward Boc-Gln-Gly-Arg-MCA and Suc-Leu-Leu-Val-Tyr-MCA. This enzymatic activity was inhibited by quail ovoinhibitor. These results suggest that quail ovoinhibitor suppresses functional responses of mouse and quail B- and T-lymphocytes via inhibition of enzymatic activity produced from the lymphocytes.