Ontogeny of mouse B lymphocytes and inactivation by antigen of early B lymphocytes.

Abstract

Taking advantage of recent findings about membrane fluidity, the biosynthetic capacities of fetal or neonatal mouse B (bone-marrow derived) lymphocytes (until 10 days after birth) and adult B lymphocytes were compared. Although early and adult lymphocytes can synthesize surface immunoglobulins, they have a different physiological behavior after interaction with a ligand (anti-immunoglobulin sera or antigen [tobacco mosaic virus or keyhole limpet hemocyanin]), in vivo or in vitro. Fetal and neonatal lymphocytes bearing surface immunoglobulins do not reexpress their membrane receptors after capping and endocytosis promoted by anti-immunoglobulin sera. Adult lymphocytes completely resynthesize their receptors after the same treatment. Intrafetal injections of hemocyanin in pregnant mice lead to a striking decrease in the number of hemocyanin-binding cells. This non-reexpression of surface immunoglobulins could be the 1st step in tolerance establishment.