Semaphorin 7A (SEMA7A)

SEMA7A is a membrane-bound semaphorin that associates with cell surfaces via a glycosylphosphatidylinositol (GPI) linkage. SEMA7A is also known as the John-Milton-Hagen (JMH) blood group antigen, an 80-kD glycoprotein expressed on activated lymphocytes and erythrocytes.

Czopik et al. (2006) found that T cells from immunized Sema7a -/- mice had increased proliferative responses to antigen that were not attributable to Sema7a deficiency on macrophages or dendritic cells. Sema7a -/- mice were prone to die at the onset of experimental autoimmune encephalomyelitis (EAE) and had higher clinical EAE scores compared with wildtype littermates. Delayed-type hypersensitivity responses were also enhanced in Sema7a -/- mice.