Expression of murine Fc receptors for IgG.
Item
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Title
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Expression of murine Fc receptors for IgG.
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Identifier
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AAI9020806
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identifier
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9020806
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Creator
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Schreiber, Ronda E.
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Contributor
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Adviser: Jay C. Unkeless
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Date
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1990
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Language
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English
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Publisher
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City University of New York.
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Subject
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Chemistry, Biochemistry | Biology, Microbiology | Biology, Molecular
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Abstract
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There are two distinct genes encoding murine low affinity Fc receptors for IgG (Fc{dollar}\sb{lcub}\gamma{rcub}{dollar}RII), muFc{dollar}\sb{lcub}\gamma{rcub}{dollar}RII{dollar}\sb\alpha{dollar} and muFc{dollar}\sb{lcub}\gamma{rcub}{dollar}RII{dollar}\sb\beta{dollar}, which are transcribed in specific cell lineages. Fc{dollar}\sb{lcub}\gamma{rcub}{dollar}RII{dollar}\sb\alpha{dollar} transcripts are present in macrophages, NK cells, and mesangial cells; Fc{dollar}\sb{lcub}\gamma{rcub}{dollar}RII{dollar}\sb\beta{dollar} transcripts are expressed in Fc{dollar}\sb{lcub}\gamma{rcub}{dollar}R-bearing lymphocytes and macrophages. A sandwich enzyme-linked immunosorbent assay (ELISA) was devised to quantify the predicted Fc{dollar}\sb{lcub}\gamma{rcub}{dollar}RII{dollar}\sb\alpha{dollar} protein. The ELISA is specific for Fc{dollar}\sb{lcub}\gamma{rcub}{dollar}RII{dollar}\sb\alpha{dollar}, and does not detect the closely related Fc{dollar}\sb{lcub}\gamma{rcub}{dollar}RII{dollar}\sb\beta{dollar} protein. Upon stimulation with IFN-{dollar}\sb{lcub}\gamma{dollar} of the Fc{dollar}\sb{lcub}\gamma{rcub}{dollar}RII{dollar}\beta{dollar}-negative macrophage cell line, J774a cells expressed enhanced levels of Fc{dollar}\sb{lcub}\gamma{rcub}{dollar}RII{dollar}\sb\alpha{dollar}. Peritoneal macrophages synthesized varying amounts of Fc{dollar}\sb{lcub}\gamma{rcub}{dollar}RII{dollar}\sb\alpha{dollar}. High levels of Fc{dollar}\sb{lcub}\gamma{rcub}{dollar}RII{dollar}\sb\alpha{dollar} were observed in resident and thioglycollate-elicited peritoneal macrophages, but no Fc{dollar}\sb{lcub}\gamma{rcub}{dollar}RII{dollar}\sb\alpha{dollar} was detected in Bacillus Calmette Guerin (BCG)-elicited macrophages. J774a cells stimulated with rIL-6 bound roughly 2-fold more anti-Fc{dollar}\sb{lcub}\gamma{rcub}{dollar}RII mAb 2.4G2 IgG than unstimulated controls. However, the Fc{dollar}\sb{lcub}\gamma{rcub}{dollar}RII{dollar}\sb\alpha{dollar}-specific ELISA showed no change in the amount of Fc{dollar}\sb{lcub}\gamma{rcub}{dollar}RII{dollar}\sb\alpha{dollar} expressed. A probe encompassing the extracellular coding sequence of Fc{dollar}\sb{lcub}\gamma{rcub}{dollar}RII{dollar}\sb\beta{dollar} hybridized to two distinct transcripts that were elevated in rIL-6-stimulated J774a cells. One of these transcripts had the same mobility in electrophoresis as Fc{dollar}\sb{lcub}\gamma{rcub}{dollar}RII{dollar}\sb\alpha{dollar}, whereas the other transcript was larger. Since it was confirmed, with an Fc{dollar}\sb{lcub}\gamma{rcub}{dollar}RII{dollar}\sb\beta{dollar}-specific probe, that J774a cells do not make Fc{dollar}\sb{lcub}\gamma{rcub}{dollar}RII{dollar}\sb\beta{dollar} mRNA, the larger transcript must encode a novel Fc{dollar}\sb{lcub}\gamma{rcub}{dollar}RII. It is likely that the increased level of binding of the anti-Fc{dollar}\sb{lcub}\gamma{rcub}{dollar}RII mAB 2.4G2 to rIL-6-induced cells represents translation of a Fc{dollar}\sb{lcub}\gamma{rcub}{dollar}R distinct from Fc{dollar}\sb{lcub}\gamma{rcub}{dollar}RII{dollar}\sb\alpha{dollar} or Fc{dollar}\sb{lcub}\gamma{rcub}{dollar}RII{dollar}\sb\beta{dollar}. The existence of such a receptor introduces further complexity to the heterogeneity of the murine Fc{dollar}\sb{lcub}\gamma{rcub}{dollar}R family.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
