Inhibition of proliferative responses of mouse spleen lymphocytes by lacto- and ovotransferrins

This study evaluated the influence of three transferrin family proteins (bovine lactotransferrin, bLf chicken ovotransferrin, cOf; quail ovotransferrin, qOf) at concentrations ranging from 10 to 50 mu g ml(-1) on proliferative responses of mouse spleen lymphocytes stimulated by lipopolysaccharide (LPS) and phytohemagglutinin (PHA). The transferrins significantly inhibited both the mitogen-induced proliferation in a dose-dependent manner. Ovotransferrins, especially qOf had cytotoxicity for the lymphocytes. There is no relationship between iron saturation and inhibitory effect of each transferrin or cytotoxicity of ovotransferrins. All these transferrins bound to CD4(+) T-lymphocytes, CD8(+) T-lymphocytes and B-lymphocytes, but no transferrin conjugated with PHA. PHA bound to lymphocytes previously incubated with each transferrin. These results indicate that the inhibition of proliferation by the transferrins and the cytoxicity of ovotransferrins are not attributable to a function of iron transport and to inactivation of nitrogen, suggesting that the hyporesponsiveness is due to interaction of lymphocytes and/or accessory cells with each transferrin.