Persistence of anti-immunoglobulin on the lymphocyte surface.

Abstract

IT is well established that addition of anti-immunoglobulin (anti-Ig) to lymphocytes expressing Ig receptors produces ‘capping’ followed by endocytosis or ‘sloughing’ of the membrane Ig, the expression of which is greatly diminished until resynthesis occurs1. Another property of anti-Ig in some species, notably the rabbit, is blastogenic activation of lymphocytes2. It is known that for the activation of lymphocytes by plant mitogens, the mitogenic substance must persist on the cell membrane for several hours before irreversible activation of the cell occurs3. Similarly, the activation of rabbit lymphocytes by antiserum to allotypic Ig determinants is largely inhibited if the Ig expressing the target allotype is added within a few hours4. Thus there is an apparent conflict between these two phenomena, one of which centres around the rapid removal of membrane Ig, the other requiring the persistence of anti-Ig for longer periods. Accordingly, experiments were designed to test the degree of retention of anti-Ig and the re-expression of membrane Ig on the surface of lymphocytes treated with anti-Ig sera and retained in tissue culture for several days.