Structural, cellular and molecular aspects of immune privilege in the testis

Abstract

The testis presents a special immunological environment, considering its property of immune privilege that tolerates alloand auto-antigens. Testicular immune privilege was oncebelievedtobemainlybasedonthesequestrationofantigensfromtheimmunesystem by the blood-testis barrier in the seminiferous epithelium. Substantial evidence supports the view that the combination of physical structure, testicular cells, and cytokines controls immune responses in the testis to preserve the structural and functional integrity of testicular immune privilege. Both systemic immune tolerance and local immunosuppression help maintain the immune privilege status. Constitutive expression of anti-inflammatory factors in testicular cells is critical for local immunosuppression. However, the testis locally generatesanefficientinnateimmunesystemagainstpathogens. Disruptionofthesemechanisms may lead to orchitis and impair fertility. This review article highlights the current understanding of structural, cellular, and molecular mechanisms underlying the unique immune environment of the testis, particularly its immune privilege status. © 2012 Li, Wang and Han.