Identification and functional characterization of mouse CD29 with a mAb

The ß1 integrin subfamily, alternatively called verylate activation antigen (VLA), has been implicated in variouscellular functions. In this study, we generated a mAb againstthe mouse ß1 subunit (CD29) to examine the functionalproperty of mouse VLA proteins. After immunization with affinity-purifiedmouse VLA-4 (4ß1), a hamster mAb, HMß1-1,was established by screening mAb that reacted with 4-negatlveneuroblastoma C1300. The antigen defined by HMß1-1was widely distributed in various mouse cell lines and HMß1-1immunoprecipitated a 110-120 kDa protein common to VLA-1 andVLA-6, indicating that HMß1-1 recognizes the ß1subunit of mouse integrins. We then examined the inhibitoryeffect of HMß1-1 on VLA-dependent cell adhesion andactivation. HMß1-1 blocked the adhesion of mouse tumorcell lines to extracellular matrix proteins including collagen,laminin and fibronectin. Moreover, splenic T cell proliferationinduced by anti-CD3 mAb and allogeneic mixed lymphocyte responsewere strongly inhibited by HMß1-1 in combination withan anti-LFA-1 mAb. We conclude that HMß1-1 reactivewith mouse CD29 can inhibit VLA-dependent cellular functionsand, thus, would be useful for studying the physiological roleof ß1 integrins in vivo.