LAIR-2 Background Information Leukocyte-associated immunoglobulin-like receptor 2 (LAIR-2), also called CD306 antigen, is a secreted 152 amino acid member of the immunoglobulin superfamily. LAIR-2 was identified by its similarity to LAIR-1. It may help modulate mucosal tolerance established by the interaction of LAIR-1 with Ep-CAM. Two isoforms have been characterized for this protein. Isoform 1, also called LAIR-2a, is the full length protein. Isoform 2, also called LAIR-2b, is missing the amino acid sequence from 122 and 138.