Manole COJOCARU1,2, Inimioara Mihaela COJOCARU3
Abstract. There are several immune privileged sites including the testis, anterior chamber of the eye, brain, central nervous system, maternal fetal interface of the placenta, hair follicles and some tumors. The testicular environment is not always tolerogenic or immunologically ignorant. The local factors and cellular components of the testis determine the immune response. It is now known that immune cells (antigen presenting cells, T cells and NK cells) involved in mounting an effective immune response are present in the testis. Both endocrine and paracrine networks coordinate to regulate testicular immune privilege. Tregs contribute to testicular immune privilege. The role of androgens in testicular immune regulation has long been underestimated; yet, accumulating evidence now shows that they orchestrate the inhibition of proinflammatory cytokine expression and shift cytokine balance toward a tolerogenic environment. Androgens also regulate the testicular immunoprivileged status. The androgens synthesized by Leydig cells suppress both systemic and testicular immune responses to auto-antigens. Moreover, several negative regulatory immune systems have been found in the testis. In particular, numerous paracrine cytokines, including various anti-inflammatory factors, would contribute to the maintenance of testicular immune privilege. The testis represents a distinct immunoprivileged site where both allo-antigens and immunogenic auto-antigens can be tolerated without evoking detrimental immune responses. Testicular innate immunity is particularly critical when systemic immunity is reduced. Here, we discuss the local cellular innate immune defense system of the testis. Impairment of immune homeostasis in the testis can result in orchitis, an etiological factor of male infertility. This review will focus on immune privilege in the testis.
Keywords: immune cells, immune privilege, immunological microenvironment, blood-testis barrier, innate immunity, testis.
DOI 10.56082/annalsarscimed.2025.2.5
1 Academy of Romanian Scientists, Bucharest, Romania
2 Titu Maiorescu University, Faculty of Medicine, Bucharest, Romania
3 Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
Correspondence: Manole COJOCARU, Academy of Romanian Scientists, Bucharest, Romania; e-mail: manole.cojocaru@yahoo.com
PUBLISHED in Annals of the Academy of Romanian Scientists Series of Medicine, Volume 6, Issue 2