I was reading Developmental biology by Gilbert and stumbled upon a fact that Sertoli cells provide protection to the developing sperms with no futher explanation.
I googled it and found a few books mentioning that it protects sperms from cell mediated immunity and antisperm antibodies. Yet I found a website called fertilitypedia that said:
Sertoli cells do not only control the process of spermatogenesis, but they are also responsible for creating so called immunologically privileged area in the testicles. It means, that Sertoli cell manage to keep blood separated from seminiferous tubules through the connection between them, called tight junction. Tight junction keeps bloodborne substances from reaching germ cells, so all stages of germ cells are protected from the body immunity. Tight junction also keeps surface antigens found on developing germ cells from eluding into the bloodstream so no autoimmune reaction could happen. Since Sertoli cells form the block between the blood and lumen of seminiferous epithelium, they are also in control of the entry and exit of nutrients, hormones and other chemicals into the tubules of the testis.
I'm unable to verify this explanation from the cited sources as none contain the mentioned information.
So my question, how does it actually protect the sperms?