The IM7 monoclonal antibody specifically reacts with all the isoforms and both alloantigens of the CD44 glycoprotein (Pgp-1, Ly-24). CD44 is expressed on hematopoietic and non-hematopoietic cells, bone marrow myeloid cells, memory T lymphocytes, periphery activated B cells, CD4+ T lymphocytes, and CD8+ T lymphocytes. The periphery B and T lymphocytes upregulate the expression of CD44. CD44 binds to hyaluronan molecules, acting as an adhesion molecule.

The IM7 antibody inhibits collagen-induced arthritis in DBA/1 mice, prevents central nervous system inflammation associated with experimental autoimmune encephalomyelitis, but exacerbates the experimental autoimmune thyroiditis in CBA/J mice.

The IM7 antibody also cross-reacts with dog, human, pig, horse, cat, and cow leukocytes.