Human tonsil B lymphocyte function. II. Pokeweed mitogen-induced plasma cell differentiation of B cell subpopulations expressing multiple heavy chain isotypes on their surface
Mudde, G.C.; Verberne, C.J.; de Gast, G.C.
Journal of Immunology 133(4): 1896-1901
1984
ISSN/ISBN: 0022-1767 PMID: 6332139 Document Number: 223141
Human tonsil non-T cells were successfully separated into surface IgM+G-ve (sIgM+G-), sIgM+G+, sIgM-G-, and sIgM-G+ B cell fractions. The 2-step separation technique used did not affect the pokeweed mitogen- (PWM) induced plasma cell differentiation of the B cells. The highest percentages of plasma cells after PWM stimulation were found in the sIgM- fractions; the lowest percentage was in the sIgM+G- fraction (20.8 .+-. 2.3%), the latter being predominantly cytoplasmic .mu.-chain-positive (c.mu.+) (84.1 .+-. 3.5%) plasma cells. In this fraction, almost no c.gamma.+ plasma cells were found. The sIgM+G+ produced c.mu.+ (47.5 .+-. 7.5%), c.gamma.+ (35.7 .+-. 5.8%) and c.alpha.+ (16.8 .+-. 4.0%) plasma cells. All 3 isotypes were found on the surface of the B cells in this fraction before PWM stimulation. The sIgM-G- fraction contained .apprx. 10% plasma cells before stimulation, which were predominantly c.gamma.+. After PWM stimulation, primarily c.alpha.+ (64.2 .+-. 4.3%) plasma cells were found. The sIgM-G+ fraction produced both c.gamma.+ (75.0 .+-. 2.3%) and c.alpha.+ (24.1 .+-. 2.5) plasma cells. A .mu. to .gamma. class switch did not occur in vitro in the sIgM+G- fraction on PWM stimulation; the sIgM+G+ fraction did not complete in vitro the .mu. to .gamma. switch it had started in vivo.