|
|
||||||||
Divisions of Rheumatology and Nephrology, Department of Internal Medicine, School of Medicine, Charlottesville, Virginia 22901
Abstract
Human circulating lymphocytes with easily detectable surface immunoglobulin have been divided into two populations, B cells and L cells. This second population lacks membrane-incorporated Ig, but has a receptor for membrane-labile cytophilic IgG. In this study purified B and L lymphocytes were examined for Fc receptors that bind aggregated IgG and IgG complexed to erythrocytes. Purified lymphocyte populations were prepared by nylon columns and by negative selection with rosetting techniques. L lymphocytes bound aggregated guinea pig and human IgG, and formed rosettes with human erythrocytes sensitized with Ripley IgG (EA). Treatment of L lymphocytes with trypsin had no effect on the receptors for IgG. B lymphocytes did not bind EA and attachment of aggregated IgG was variable; up to one-third of these cells fixed aggregated human IgG to the cell membrane. Trypsin treatment abolished binding of Agg-IgG to B cells in sharp contrast to its effect on L cells. Furthermore, double-label immunofluorescence studies showed that cells with both membrane-incorporated Ig and receptors for aggregated guinea pig IgG were rare. These studies indicate that human peripheral blood B lymphocytes lack a high affinity, trypsin-resistant Fc receptor that is present on L lymphocytes.
Footnotes
1 This work was supported by The John A. Hartford Foundation Grant 74466, United States Public Health Service Grant AM 11766, American Cancer Society Grant PDT-4A, United States Public Health Service Clinical Pharmacology Training Grant GM-10, and Renal Unit Local Fund.
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |