Evidence that glycoprotein 96 (B2), a stress protein, functions as a Th2-specific costimulatory molecule.

Banerjee, Pinaki P and Vinay, D S and Mathew, Ajith and Raje, Manoj and Parekh, Vrajesh and Prasad, Durbaka V R and Kumar, Anil and Mitra, Debashis and Mishra, G C (2002) Evidence that glycoprotein 96 (B2), a stress protein, functions as a Th2-specific costimulatory molecule. Journal of immunology (Baltimore, Md. : 1950), 169 (7). pp. 3507-18. ISSN 0022-1767

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Abstract

After the engagement of Ag receptor, most of the Th cells for their optimal activation require a second (costimulatory) signal provided by the APCs. We demonstrate the isolation and characterization of a 99- to 105-kDa protein (B2), from LPS-activated B cell surface, and its function as a Th2-specific costimulatory molecule. Appearance of B2 as a single entity on two-dimensional gel electrophoresis and as a distinct peak in reverse-phase HPLC ascertains the fact that B2 is homogeneous in preparation. Electron microscopy as well as competitive binding studies reveal that (125)I-labeled B2 specifically binds anti-CD3-activated T cell surface and also competes with its unlabeled form. Internal amino acid sequences of B2 are found to be identical with stress protein gp96. The identity of B2 as gp96 is also revealed by immunological characterization and by confocal microscopic colocalization studies of B2 and gp96 on LPS-activated B cells. Confocal imaging studies also demonstrate that gp96 can be induced on B cell surface without association of MHC molecules. Furthermore, the novel role of gp96 in Th cell proliferation skewing its differentiation toward Th2 phenotype has also been established. Ab-mediated blocking of gp96-induced signaling not only abrogates in vitro proliferation of CD4(+) T cells, but also diminishes the secretion of Th2-specific cytokines. Notably, the expression of CD91 (receptor of gp96/B2) is up-regulated on anti-CD3-activated Th cells and also found to be present on Th1 and Th2 subsets.

Item Type:	Article
Additional Information:	Copyright of this article belongs to American Association of Immunologists.
Subjects:	Q Science > QR Microbiology > QR180 Immunology
Depositing User:	Dr. K.P.S.Sengar
Date Deposited:	06 Feb 2012 18:19
Last Modified:	09 Jan 2015 10:46
URI:	http://crdd.osdd.net/open/id/eprint/884

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