Antigen-induced Fc receptor-dependent and -independent B cell desensitization: An elevation in [Ca2+]i is not sufficient and protein kinase C activation is not required for these pathways of surface IgM-mediated desensitization

Alan H. Lazarus, Gordon Mills, Andrew R. Crow, Terry L. Delovitch

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8 Citations (Scopus)

Abstract

The interaction of an Ag ligand with its B cell surface Ig (sIg) receptor can occur via an FcR-dependent or -independent pathway. We previously found that transfected TNP-specific B cells undergo both Ca2+ signaling and desensitization upon interaction with the thymus-dependent Ag TNP-OVA. Similarly, we showed that these B cells can also be desensitized by cross-linking sIg to the FcγR via the formation of an Ag-antibody bridge. Thus, Ag-specific B cells can be desensitized by two different Ag-dependent events, one mediated by Ag-sIg interaction and the other by sIg-FcγR cross-linking. Inas-much as Ag-sIg and sIg-FcγR interactions lead to positive and negative signaling, it was of interest to determine whether B cell desensitization mediated by these interactions occurs by one of the well known signaling pathways in B cells. We found that Ag-induced changes in [Ca2+]i could be readily dissociated from Ag-induced desensitization, indicating that a Ca2+-independent pathway is likely responsible for this pathway of desensitization. To determine if PKC plays a role in B cell desensitization mediated by either Ag or sIg-FcγR interaction, PKC was downregulated by long term exposure to 12-0-tetradecanoylphorbol 13-acetate or inhibited by exposure of cells to staurosporine. The PKC down-regulated and inhibited cells underwent similar Ag- and FcγR-dependent desensitization compared to cells containing active PKC. Taken together, these data indicate that Ag-induced desensitization of B cell signaling likely involves an event(s) that occurs either upstream or independent of Ag-induced elevations in [Ca2+]i and PKC activation.

Original languageEnglish (US)
Pages (from-to)1739-1745
Number of pages7
JournalJournal of Immunology
Volume147
Issue number6
StatePublished - Sep 15 1991
Externally publishedYes

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Fc Receptors
Protein Kinase C
Immunoglobulin M
B-Lymphocytes
Antigens
Staurosporine
Cell Surface Receptors
Tetradecanoylphorbol Acetate
Thymus Gland
Antibody Formation
Down-Regulation
Ligands

ASJC Scopus subject areas

  • Immunology

Cite this

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title = "Antigen-induced Fc receptor-dependent and -independent B cell desensitization: An elevation in [Ca2+]i is not sufficient and protein kinase C activation is not required for these pathways of surface IgM-mediated desensitization",
abstract = "The interaction of an Ag ligand with its B cell surface Ig (sIg) receptor can occur via an FcR-dependent or -independent pathway. We previously found that transfected TNP-specific B cells undergo both Ca2+ signaling and desensitization upon interaction with the thymus-dependent Ag TNP-OVA. Similarly, we showed that these B cells can also be desensitized by cross-linking sIg to the FcγR via the formation of an Ag-antibody bridge. Thus, Ag-specific B cells can be desensitized by two different Ag-dependent events, one mediated by Ag-sIg interaction and the other by sIg-FcγR cross-linking. Inas-much as Ag-sIg and sIg-FcγR interactions lead to positive and negative signaling, it was of interest to determine whether B cell desensitization mediated by these interactions occurs by one of the well known signaling pathways in B cells. We found that Ag-induced changes in [Ca2+]i could be readily dissociated from Ag-induced desensitization, indicating that a Ca2+-independent pathway is likely responsible for this pathway of desensitization. To determine if PKC plays a role in B cell desensitization mediated by either Ag or sIg-FcγR interaction, PKC was downregulated by long term exposure to 12-0-tetradecanoylphorbol 13-acetate or inhibited by exposure of cells to staurosporine. The PKC down-regulated and inhibited cells underwent similar Ag- and FcγR-dependent desensitization compared to cells containing active PKC. Taken together, these data indicate that Ag-induced desensitization of B cell signaling likely involves an event(s) that occurs either upstream or independent of Ag-induced elevations in [Ca2+]i and PKC activation.",
author = "Lazarus, {Alan H.} and Gordon Mills and Crow, {Andrew R.} and Delovitch, {Terry L.}",
year = "1991",
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T1 - Antigen-induced Fc receptor-dependent and -independent B cell desensitization

T2 - An elevation in [Ca2+]i is not sufficient and protein kinase C activation is not required for these pathways of surface IgM-mediated desensitization

AU - Lazarus, Alan H.

AU - Mills, Gordon

AU - Crow, Andrew R.

AU - Delovitch, Terry L.

PY - 1991/9/15

Y1 - 1991/9/15

N2 - The interaction of an Ag ligand with its B cell surface Ig (sIg) receptor can occur via an FcR-dependent or -independent pathway. We previously found that transfected TNP-specific B cells undergo both Ca2+ signaling and desensitization upon interaction with the thymus-dependent Ag TNP-OVA. Similarly, we showed that these B cells can also be desensitized by cross-linking sIg to the FcγR via the formation of an Ag-antibody bridge. Thus, Ag-specific B cells can be desensitized by two different Ag-dependent events, one mediated by Ag-sIg interaction and the other by sIg-FcγR cross-linking. Inas-much as Ag-sIg and sIg-FcγR interactions lead to positive and negative signaling, it was of interest to determine whether B cell desensitization mediated by these interactions occurs by one of the well known signaling pathways in B cells. We found that Ag-induced changes in [Ca2+]i could be readily dissociated from Ag-induced desensitization, indicating that a Ca2+-independent pathway is likely responsible for this pathway of desensitization. To determine if PKC plays a role in B cell desensitization mediated by either Ag or sIg-FcγR interaction, PKC was downregulated by long term exposure to 12-0-tetradecanoylphorbol 13-acetate or inhibited by exposure of cells to staurosporine. The PKC down-regulated and inhibited cells underwent similar Ag- and FcγR-dependent desensitization compared to cells containing active PKC. Taken together, these data indicate that Ag-induced desensitization of B cell signaling likely involves an event(s) that occurs either upstream or independent of Ag-induced elevations in [Ca2+]i and PKC activation.

AB - The interaction of an Ag ligand with its B cell surface Ig (sIg) receptor can occur via an FcR-dependent or -independent pathway. We previously found that transfected TNP-specific B cells undergo both Ca2+ signaling and desensitization upon interaction with the thymus-dependent Ag TNP-OVA. Similarly, we showed that these B cells can also be desensitized by cross-linking sIg to the FcγR via the formation of an Ag-antibody bridge. Thus, Ag-specific B cells can be desensitized by two different Ag-dependent events, one mediated by Ag-sIg interaction and the other by sIg-FcγR cross-linking. Inas-much as Ag-sIg and sIg-FcγR interactions lead to positive and negative signaling, it was of interest to determine whether B cell desensitization mediated by these interactions occurs by one of the well known signaling pathways in B cells. We found that Ag-induced changes in [Ca2+]i could be readily dissociated from Ag-induced desensitization, indicating that a Ca2+-independent pathway is likely responsible for this pathway of desensitization. To determine if PKC plays a role in B cell desensitization mediated by either Ag or sIg-FcγR interaction, PKC was downregulated by long term exposure to 12-0-tetradecanoylphorbol 13-acetate or inhibited by exposure of cells to staurosporine. The PKC down-regulated and inhibited cells underwent similar Ag- and FcγR-dependent desensitization compared to cells containing active PKC. Taken together, these data indicate that Ag-induced desensitization of B cell signaling likely involves an event(s) that occurs either upstream or independent of Ag-induced elevations in [Ca2+]i and PKC activation.

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