Abstract
The extracellular matrix protein (ECM) receptor, so-called integrin, may play important roles in cellular migration, proliferation and differentiation, and these receptors may also be implicated in T cell migration, adhesion and activation. We previously reported that integrin-like molecules might be involved in the lymphokine-activated killer (LAK) cell cytolytic activity against some target cells by using a monoclonal antibody (mAb), RMV-7.
Immunoprecipitation and western blotting studies revealed that the antigen recognized by RMV-7 was identical with mouse vitronectin receptor (VNR; αvβ3), but RMV-7 could not bind to αv negative mouse platelets, indicating that RMV-7 recognizes the αv subunit of integrins. In this study, I generated an mAb against the mouse integrin β3 subunit (CD61) to examine the biological functions of the integrin β3 subfamily in the mouse system. After immunization with affinity purified VNR, a hamster mAb, HMβ3, was established by screening mAbs that reacted with T cell hybridoma (αv positive) and platelet (αv negative). HMβ3 reacted with not only T cell hybridomas and platelets but also activated T cells and megakaryocytes. Moreover, adhesion of activated T cells to fibronectin, vitronectin and fibrinogen was strongly inhibited by HMβ3. I conclude that HMβ3 will be useful for studying the physiological role of β3 integrins in vivo.
