Functional studies of IgD-receptor-positive murine T delta cells and soluble IgD-binding factor.
Item
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Title
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Functional studies of IgD-receptor-positive murine T delta cells and soluble IgD-binding factor.
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Identifier
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AAI9510736
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identifier
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9510736
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Creator
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Yang, Yi Jun.
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Contributor
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Adviser: Richard F. Coico
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Date
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1994
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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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Health Sciences, Immunology | Biology, Cell
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Abstract
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The biological role of immunoglobulin D (IgD) has remained enigmatic since it was discovered two decades ago. IgD is found in very low concentration in the serum and is co-expressed with IgM on the majority of mature B lymphocytes. Evidence from previous studies has shown that receptors specific for IgD (IgD-R) are expressed by human CD4{dollar}\sp+{dollar} and CD8{dollar}\sp+{dollar} T cells whereas IgD-R appear to be restricted to the CD4{dollar}\sp+{dollar} T cell population in the mouse. IgD-R are induced in both human and murine T cells by their exposure to cross-linked IgD or lymphokines such as IL-4, IL-2, and IFN-gamma. IgD-R{dollar}\sp+{dollar} T cells (T{dollar}\delta{dollar}) are also found to release IgD-Binding factor (IgD-BF) by similar induction. Previous in vivo functional studies of murine T{dollar}\delta{dollar} cells have demonstrated that up-regulation of these receptors correlates with increased helper activity as measured by enhanced primary and secondary antibody responses to various antigens.;The goal of this study is to gain some insight into the mechanism by which IgD augments antibody responses. By establishing an in vitro assay system, we have been able to reproduce the previous in vivo studies, Furthermore, our results showed that IgD-induced augmentation of humoral antibody response was mediated by physical contact of B cells with antigen-specific TCR bearing T{dollar}\delta{dollar} cells, but not by soluble factors released by T{dollar}\delta{dollar} cells, Our study also revealed that T{dollar}\delta{dollar} cells facilitated antigen presentation by IgD-bearing B cells. Preliminary studies on characterizing IgD-BF and IgD-R demonstrated heterogeneous species of IgD-BF and IgD-R with molecular weights ranging from 20 kDa to 69 kDa, as recognized by both IgD and E11. In conclusion, our studies suggest that IgD plays an important regulatory role in humoral antibody responses by: (1) upon being cross-linked by antigen, inducing IgD-R and functioning as adhesion molecules that facilitate T-B interaction; and (2) upon B cell activation, terminating the T-B interaction by down-regulating expression, the negative effect of which is further augmented by the release and degradation of IgD-BF.
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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.
