Immunoglobulin biosynthesis in vitro after stimulation of pig blood lymphocytes with mitogen.

The biosynthesis of immunoglobulin (Ig) by pig blood lymphocytes after mitogen stimulation with lipopolysaccharide (LPS) and anti-Ig serum has been assessed by incorporation of 3H--leucine into secreted Ig. Lymphocytes prepared from defibrinated and heparinised blood responded to LPS with mitosis, but Ig biosynthesis (predominantly IgM) only occurred with heparinised blood lymphocytes. Anti-Ig treatment produced pronounced mitosis in both preparations but no significant Ig biosynthesis in either. Mitosis was induced by anti-IgM (mu- and L chains), anti-mu and anti-IgG (gamma- and L chains) but only weakly by anti-gamma in both types of preparation. Lymphocytes from heparinised blood gave preparations with higher percentages of surface-Ig-bearing cells by direct immunofluorescence (defibrinated 14.0%, heparinised 25.2%).