The R7-1 monoclonal antibody reacts with human LFA-1α (lymphocyte function-associated antigen 1 alpha) also known as integrin alpha L chain and CD11a. Specifically, this antibody recognizes an epitope within the I-domain of LFA-1α. LFA-1α and CD18 combine to form LFA-1, a 180 kDa glycoprotein and a member of the integrin family. LFA-1 is expressed on the surface of all leukocytes including lymphocytes, monocytes, macrophages, and granulocytes. LFA-1 plays a central role in leukocyte intercellular adhesion through interactions with its ligands, ICAM-1 (CD54), ICAM-2 (CD102), and ICAM-3 (CD50), and also functions in lymphocyte costimulatory signaling. The R7-1 antibody is a neutralizing antibody.