title: B-cell subsets defined by the Fc epsilon R.
abstract: The data summarized herein demonstrate the utility of the low-affinity Fc epsilon R in delineating murine B-cell subsets. In the peritoneal cavity, the Fc epsilon R appears to be a reliable marker in distinguishing between conventional (Fc epsilon R+) and Ly-1/sister (Fc epsilon R-) B cells. In the spleens of normal animals, flow cytometric and histologic studies established that a distinct population of Fc epsilon R- B cells is also present and comprises the marginal zones. Thus in the spleen, the Fc epsilon R may be the first murine marker to allow for selective purification and analysis of marginal zone B cells. Although it is unlikely that splenic Fc epsilon R- B cells are directly related to peritoneal Fc epsilon R- Ly-1/sister B cells, further studies will be required to address this question. Analysis of autoimmune mice revealed that the splenic Fc epsilon R- subset is greatly expanded in these animals and indicates that the Fc epsilon R may be a sensitive indicator of abnormalities within the B-cell compartment. Additional studies compared the functional capacity of Fc epsilon R+ and Fc epsilon R- B cells and tested the ability of these populations to isotype-switch and respond to polyclonal stimuli. The results showed that Fc epsilon R+ and Fc epsilon R- B cells from both the peritoneum and spleen can switch to produce IgG, and all but the peritoneal Fc epsilon R- B cells can switch to the IgE class. This latter result is certainly interesting and demonstrates an important functional difference between peritoneal and splenic Fc epsilon R- B cells. Finally, experiments with B-cell mitogens showed further differences between the Fc epsilon R+ and Fc epsilon R- subsets. Whereas Fc epsilon R- B cells appeared to be more sensitive to LPS stimulation, Fc epsilon R+ B cells were clearly more responsive to an anti-IgM signal. Taken together, the results show that the Fc epsilon R is likely to be useful in separating B cells with different phenotypic, histologic, and functional characteristics.
authors.affiliation: Department of Pathology, University of Iowa College of Medicine, Iowa City 52242.
authors.forename: T
authors.initials: T
authors.lastname: Waldschmidt
authors.forename: K
authors.initials: K
authors.lastname: Snapp
authors.forename: T
authors.initials: T
authors.lastname: Foy
authors.forename: L
authors.initials: L
authors.lastname: Tygrett
authors.forename: C
authors.initials: C
authors.lastname: Carpenter
mesh_terms: D000375:Aging / Q000276:immunology; D000818:Animals; D015703:Antigens, CD / Q000032:analysis / Q000276:immunology*; D000944:Antigens, Differentiation, B-Lymphocyte / Q000032:analysis / Q000378:metabolism*; D016175:B-Lymphocyte Subsets / Q000276:immunology*; D018956:CD5 Antigens; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D008213:Lymphocyte Activation; D051379:Mice; D011961:Receptors, Fc / Q000032:analysis / Q000378:metabolism*; D017455:Receptors, IgE; D013154:Spleen / Q000276:immunology
chemical_list: D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte; D018956:CD5 Antigens; D011961:Receptors, Fc; D017455:Receptors, IgE; D007073:Immunoglobulin E