The mature, resting immunoglobulin (Ig) M, IgD+ B lymphocyte can be induced by T cells to proliferate, switch isotype, and differentiate into Ig- secreting or memory cells. Furthermore, B cell activation results in the de novo expression or loss of a number of cell surface molecules that function in cell recirculation or further interaction with T cells. Here, a novel fluorescent technique reveals that T-dependent B cell activation induces cell surface changes that correlate with division cycle number. Furthermore, striking stepwise changes are often centered on a single round of cell division. Particularly marked was the consistent increase in IgG1+ B cells after the second division cycle, from an initial level of <3% IgG1+ to a plateau of ~40% after six cell divisions. The relationship between the percentage of IgG1+ B cells and division number was independent of time after stimulation, indicating a requirement for cell division in isotype switching. IgD expression became negative after four divisions, and a number of changes centered on the sixth division, including the loss of IgM, CD23, and B220. The techniques used here should prove useful for tracking other differentiation pathways and for future analysis of the molecular events associated with stepwise differentiation at the single cell level.

Item Type:	Refereed Article
Research Division:	Medical and Health Sciences
Research Group:	Immunology
Research Field:	Cellular Immunology
Objective Division:	Expanding Knowledge
Objective Group:	Expanding Knowledge
Objective Field:	Expanding Knowledge in the Environmental Sciences
Author:	Lyons, AB (Dr Bruce Lyons)
ID Code:	8542
Year Published:	1996
Web of Science® Times Cited:	280
Deposited By:	Pathology
Deposited On:	1996-08-01
Last Modified:	2011-08-19
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