Identification of MAGE-1 and MAGE-4 proteins in spermatogonia and primary spermatocytes of testis.

The MAGE genes encoding tumor rejection antigens recognized by CTLs are expressed at the mRNA level in various cancers and in the testis but not in the other normal tissues. The expression of MAGE-1 or MAGE-4 protein in the testicular cells was studied immunohistochemically with the antibodies to the recombinant MAGE-1 or MAGE-4 protein. Both proteins were identified in the nucleus and cytoplasm of spermatogonia and in primary spermatocytes but not in spermatids or Sertoli's cells. Therefore, MAGE proteins are normal tissue antigens compartmentalized in particular testicular cells playing an important role in the early phase of the spermatogenesis.