CD108 is an 80 kD GPI-linked membrane-bound semaphorin, also known as JMH blood group antigen, semaphorin 7A, H-SEMA, and SEMAL. It contains an Ig-like domain and is expressed at low levels on erythrocytes and lymphocytes. The expression of CD108 on lymphocytes is upregulated upon activation. CD108 is a guidance protein known for immunomodulatory effects that has been shown to enhance central and peripheral axon growth. CD108 interacts with plexin C1. The MEM-150 antibody has been shown to be useful for flow cytometry, Western blotting, and immunoprecipitation.