Document 0850
 DOCN  M9650850
 TI    Immunosuppressive mechanisms in semen: implications for contraception.
 DT    9605
 AU    Kelly RW; Medical Research Council Reproductive Biology Unit, University
       of; Edinburgh Centre for Reproductive Biology, UK.
 SO    Hum Reprod. 1995 Jul;10(7):1686-93. Unique Identifier : AIDSLINE
       MED/96033129
 AB    The immunosuppressive effects of human seminal plasma are mediated by
       several factors. The prostaglandins (PG) of the E series (PGE and
       19-hydroxy PGE) predominate and raise intracellular cAMP in leukocytes.
       By this mechanism they suppress lymphocyte proliferation, natural killer
       (NK) cell activity and are likely to modify cytokine release from
       antigen presenting cells (APC). In this way, acquired and innate
       responses (including immune surveillance) in the reproductive tract will
       be curtailed, at least temporarily, after intercourse. Semen contains
       several inhibitors of complement and a unique reservoirs of CD59, a
       major complement inhibitor, is found on the prostasomes which are
       sub-micron organelles with lipid membranes. The prostasomes also inhibit
       lymphocyte proliferation and the activity of phagocytic cells. Other
       suppressive agents are also present in semen and may exert specific
       effects, for example, transforming growth factor-beta which may inhibit
       primed responses to antigen, and receptors for Fc fraction of
       gamma-globulin which might bind inflammatory agents. A thesis is
       proposed that the balance between maximum chances of survival for
       spermatozoa and minimum chances for micro-organisms has been disturbed
       by an increased use of non-barrier contraception, an increase in
       population mobility and sexual contact and the arrival of new diseases
       such as AIDS. A further major concern is that following infection of
       cells of the cervix with virus, repeated exposure to human seminal
       plasma may accelerate the progression of disease.
 DE    Complement/PHYSIOLOGY  *Contraception  Cytokines/PHYSIOLOGY  Disease
       Progression  Female  Human  Immune System/PHYSIOLOGY  *Immune Tolerance
       Male  Prostaglandins/PHYSIOLOGY  Semen/*IMMUNOLOGY  Sexually Transmitted
       Diseases/PHYSIOPATHOLOGY  JOURNAL ARTICLE  REVIEW  REVIEW, TUTORIAL

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).