Current challenges in the modern male immune system

The tripartite network, including the nervous, immune, and endocrine systems, plays a significant role in regulatory and effector processes in the male body. On the one hand, males perform their reproduction function by generating spermatozoa in conditions of self-tolerance maintenance because most spermatozoa antigens (“sequestrated antigens”) are unknown to the immune system. On the other hand, in everyday life, a male body encounters hostile external infections, some of which colonize the skin and barrier surfaces and present a cancer threat to male genital tracts. This is human papillomavirus (HPV), the “silent killer”. Therefore, the male immune system has to function in a contradictory situation using either active immune responses, self-tolerance mechanisms, or both simultaneously. This review focused on the functional organization of the male immune system, including its coordination with the nervous and endocrine systems, and immune processes at the level of the whole organism, as well as on obvious changes, which have currently happened. The male immune system should function in conditions of the strong influence of testosterone and biosocial impulses coming from the nervous system. In the last century, researchers obtained data showing a decrease in the male reproduction function because of a stable negative dynamic of spermatozoa count and quality. Nowadays, depressing statistical indicators of male fertility have been published. 15% of couples are unable to conceive a child, where 50% of the causes of infertility relate to males, and up to 15% of male infertility cases are due to immunological disorders. It can be assumed that the male immune system starts to function when self-tolerance is partially lost, and the previous balance has been destroyed. Furthermore, sperm allergy has become a new topic in male immunology.