Distinct structural and functional epitopes of the alpha E beta 7 integrin.
Intestinal intraepithelial lymphocytes (iIEL) are predominantly CD3+, CD8+ T lymphocytes located above or adjacent to the mucosal basement membrane. Although they are positioned to interact with intercellular luminal antigen or with enterocytes, the function of iIEL remains unknown. Most (> 85%) of the iIEL express the alpha E beta 7 integrin which appears to be involved in the adhesion of lymphocytes to epithelial cells. We report the characterization of three monoclonal antibodies (mAb) termed alpha E7-1, alpha E7-2, and alpha E7-3, that react with the alpha E beta 7 integrin recognized by the previously described mAb HML-1 as demonstrated by identical sodium dodecyl sulfate-polyacrylamide gel electrophoresis mobility and charge. Flow cytometric analysis of antibody cross-blocking indicated that these mAb recognize distinct epitopes of alpha E beta 7. While all of the mAb were capable of blocking the adhesion of cultured iIEL to a breast epithelial cell line, only HML-1 and alpha E7-1 (which recognize an identical or closely related epitope) were co-stimulatory with suboptimal concentrations of anti-CD3 mAb in inducing proliferation of cultured iIEL. Thus, these mAb appear to recognize functionally distinct epitopes of alpha E beta 7 and will be useful to study relationships between the structure and function of this integrin.
Russell
G J
GJ
Department of Pediatrics, Massachusetts General Hospital, Harvard Medical School, Boston 02114.
Parker
C M
CM
Cepek
K L
KL
Mandelbrot
D A
DA
Sood
A
A
Mizoguchi
E
E
Ebert
E C
EC
Brenner
M B
MB
Bhan
A K
AK
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D002448:Cell Adhesion; D002460:Cell Line; D000939:Epitopes; D016326:Extracellular Matrix Proteins / Q000502:physiology; D006801:Humans; D016023:Integrins / Q000737:chemistry / Q000276:immunology* / Q000502:physiology; D007413:Intestinal Mucosa / Q000276:immunology*; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000737:chemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D008970:Molecular Weight; D016212:Transforming Growth Factor beta / Q000494:pharmacology
D000911:Antibodies, Monoclonal; D000939:Epitopes; D016326:Extracellular Matrix Proteins; D016023:Integrins; D016212:Transforming Growth Factor beta; C070709:integrin alphaEbeta7