A small-molecule, tight-binding inhibitor of the integrin α4β1 blocks antigen-induced airway responses and inflammation in experimental asthma in sheep

W. M. Abraham, A. Gill, A. Ahmed, M. W. Sielczak, I. T. Lauredo, Y. Botinnikova, K. C. Lin, B. Pepinsky, D. R. Leone, R. R. Lobb, S. P. Adams

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87 Scopus citations


The leukocyte integrin very late antigen-4 (α4β1, CD49d/CD29) is an adhesion receptor that plays an important role in allergic inflammation and contributes to antigen-induced late responses (LAR) and airway hyperresponsiveness (AHR). In this study, we show that single doses of a new small-molecule, tight-binding inhibitor of α4, BIO-1211, whether given by aerosol or intravenously, either before or 1.5 h after antigen challenge blocks allergen-induced LAR and post-antigen-induced AHR in allergic sheep. Multiple treatments with doses of BIO-1211 that were ineffective when given singly, were protective. BIO-1211 also provided dose-dependent inhibition of the early airway response (EAR) to antigen. In conjunction with the functional protection against the antigen-induced LAR and AHR, sheep treated with BIO-1211 before challenge showed significantly reduced: (1) numbers of eosinophils in bronchoalveolar lavage (BAL), (2) BAL levels of the inflammatory marker tissue kallikrein, and (3) numbers of inflammatory cells (lymphocytes, eosinophils, metachromatic staining cells, and neutrophils) in bronchial biopsies obtained after challenge when compared with corresponding biopsies after vehicle treatment. More importantly, we show for the first time that an inhibitor of α4 was able to reverse post-antigen-induced AHR, thereby decreasing the time of recovery from the normal period of > 9 d to 3 d. Our results show that effective inhibition of antigen-induced airway responses can be achieved with single doses of a potent small-molecule inhibitor of α4 and that such agents may be used therapeutically, as well as prophylactically, to alleviate allergen-induced inflammatory events. These data provide further support and extend the evidence for the role of α4 integrins in the pathophysiologic events that follow airway antigen challenge.

Original languageEnglish (US)
Pages (from-to)603-611
Number of pages9
JournalAmerican journal of respiratory and critical care medicine
Issue number2 I
StatePublished - Jan 1 2000

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine
  • Critical Care and Intensive Care Medicine


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