Analysis of cell-free human α1 integrin with a monoclonal antibody to the I-domain: Detection in ocular fluid and function as an adhesion substrate

Ilan Bank, Jarmo Kapyla, Aharon Grinbaum, Ram Doolman, Jonathan Bank, Ben Ami Sela

Research output: Contribution to journalArticlepeer-review

Abstract

The α1β1 integrin, an inserted (I) domain containing collagen receptor, is expressed in the cell surface membrane of normal and malignant cells, and may play a role in their migration through tissues or in metastatic spread. Here we report that a functional anti-human α1β1 integrin monoclonal antibody (mAb) (1B3.1) directly and specifically binds plastic bound recombinant human α1 I-domain protein containing the collagen binding site. Detection was diminished by acidification of the I-domain protein but was enhanced by increasing concentrations of Mg2+ cation. Furthermore, we detected binding of the mAb to proteins from the ocular fluids of 6 patients, with the highest concentration, corresponding to 22.1 ng/ml of I-domain, found in a sample from the eye of a patient with metastatic lung adenocarcinoma. Interestingly, we found that both SKNSH neuroblastoma cells and virally transformed human T cells adhered specifically to plastic wells coated with either immobilized collagen IV or α1 I-domain. MAb 1B3.1 inhibited adhesion to collagen IV but not to immobilized I-domain. These results suggest a novel function for cell free α1 I-domain as a substrate for cellular adhesion, which may have relevance in tumor spread in vivo.

Original languageEnglish
Pages (from-to)113-123
Number of pages11
JournalCell Communication and Adhesion
Volume8
Issue number3
DOIs
StatePublished - 2001
Externally publishedYes

Keywords

  • Collagen
  • I-domain
  • Integrins
  • VLA-1
  • α1β1 integrin

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