The 60 kDa heat shock protein in human semen: relationship with antibodies to spermatozoa and Chlamydia trachomatis.

The presence of the 60 kDa heat shock protein (hsp60) in seminal fluid and its relationship to sperm autoimmunity or a localized immune response to Chlamydia trachomatis were examined. Semen from 64 male partners of infertile couples with no history of a chlamydial infection were investigated. Hsp60 was identified by an enzyme-linked immunosorbent assay (ELISA) using a monoclonal anti-hsp60 antibody bound to wells of a microtitre plate and a polyclonal anti-hsp60 antibody for detection. Antisperm antibodies on motile spermatozoa were detected by immunobead binding, while antichlamydial immuno-globulin (Ig) A and IgG in seminal fluid were identified by a commercial ELISA (SeroELISA: Savyon Diagnostics, Beer-Sheva, Israel). RNA was purified from isolated seminal round mononuclear cells and tested for hsp60-specific mRNA by a reverse transcription polymerase chain reaction ELISA. Hsp60 was present in semen from nine (14.1%) men, 12 (18.8%) men had antisperm autoantibodies. 16 (25.0%) were positive for antichlamydial IgA and 17 (26.6%) had detectable hsp60-specific mRNA. The presence of hsp60 in semen correlated with the occurrence of antichlamydial IgA (P = 0.0005), hsp60 mRNA (P = 0.04) and antisperm antibodies (P = 0.05). Thus, hsp60 was present in a soluble form in semen primarily in men with evidence of immune system activation within their genital tract. The role of hsp60 in promoting or inhibiting immune responses within the genital tract remains to be determined.