Control of 
Integrin Function
LOCALIZATION OF STIMULATORY EPITOPES (*)
- From the (1)Rheumatic Disease Unit Research Laboratory, Departments of Internal Medicine,
- (2)Immunology, and
- (3)Medical Microbiology, University of Manitoba, Winnipeg MB R3A 1M4, Canada
- §To whom correspondence should be addressed: RDU Research Laboratory, RR014 800 Sherbrook St., Winnipeg MB R3A 1M4, Canada. Fax: 204-787-2420; :jwilkin{at}ccu.umanitoba.ca.
Abstract
The β
integrins can be expressed on the surface of cells in a latent form, which is activated by a variety of stimuli. As an approach
to examining the transition to an active receptor, a panel of stimulatory antibodies to β
were produced and characterized. These antibodies induced adherence of the T-leukemic cell line Jurkat to collagen and fibronectin.
Competitive antibody binding assays indicated the existence of at least three distinct epitope clusters A (B3B11, JB1B, 21C8),
B (B44, 13B9), and C(N29) defined by the indicated antibodies. Two antibodies to the A site, JB1B and B3B11, were shown to
localize to positions 671-703 and 657-670, respectively, of the β
. This region is located in an area encompassing a predicted disulfide bond between linearly distant cysteines in β
(Cys
-Cys
). The homologous region of the β
integrin (490-690 and 602-690) has been shown to be one of the sites recognized by stimulatory antibodies to ligand-induced
binding sites. The present results indicate the existence of multiple stimulatory regions and suggest considerable homology
between the locations of β
and β
regulatory sites.
Footnotes
-
↵* This research was supported by grants from the Manitoba Health Research Council, the Medical Research Council, and the Canadian Arthritis Society. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
-
↵1 The abbreviations used are:
- PBS
-
phosphate-buffered saline
- CHO
-
Chinese hamster ovary
- BSA
-
bovine serum albumin
- bp
-
base pair(s).
-
↵2 H. Ni, A. Li, and J. A. Wilkins, unpublished data.
-
↵3J. A. Wilkins, unpublished observations.
-
- Received July 3, 1995.
- Revision received October 13, 1995.
- © 1996 by The American Society for Biochemistry and Molecular Biology, Inc.
