Anti-Sperm Antibodies (ASA)
1. Antisperm antibodies?
- They exist; only a couple specific kinds can cause infertility, but w in vitro fertilization not
much research is done on them anymore.
2. What can fertilization be stopped by?
- Anti-sperm Abs (ASAs), which block binding of sperm to the zona pellucida and can be
produced by both genders.
3. What is the incidence of sperm autoimmunity in infertile couples?
- 9-36% (male/autoantigenic=8-21%, female/isoantigenic=6-23%).
4. What do female repro tracts protect against?
- Invading pathogens, but should not attack sperm cells or the developing embryo. Protects
against infectious agents. Protects establishment and maintenance of pregnancy. Acts adversely
on fertility by generating ASAs.
5. Do ASAs fix complement? Which isotypes are they primarily?
- No, both are primarily of the IgA and IgG-4 isotype.
6. What might happen if IgG-3 is present in the female reproductive tract?
- Complement activation and sperm damage may result.
7. What do ASAs in the cervical mucus do in regards to fertility?
- Can interfere via various mechanisms: inhibition of sperm migration into/through the cervical
canal, complement-dependent damage (IgG-3) of sperm membrane damage, phagocytosis of Abbound sperm by phagocytic cell (IgA, IgG), pregnant women with ASAs may have higher rate of
spontaneous abortion.
8. If a concurrent infection in the female genital tract, what might happen to the sperm?
- They might become "innocent bystanders." Women with PID have high incidence of ASAs.
9. Why might ASAs arise in women?
- Because of a deficiency of one or more of the immunosuppressive factors in the partner's
semen.
10. What generates the immune response to sperm?
- After exposure to sperm in both fertile and infertile women.
11. How is an immune response elicited in fertile women?
- ASAs elicit the production of anti-idiotypic Abs which neutralize the ASA response.
12. How is an immune response elicited in infertile women?
- Anti-idiotypic Ab production is weak/absent.
13. What is anti-idiotype?
- An Ab that binds to the Ag-combining site of another Ab to either suppress or enhance the
immune response, in this case essentially neutralizing Abs.
14. How does the insufficiency to neutralize the ASA response result in infertility?
- 1) An inherent lack of anti-idiotypic Ab response to the ASA production.
- 2) A hyperimmunization with sperm Ags as a concurrent event with pre-existing infection.
15. Two sperm Ag's with a role in immuno-infertility?
- FA-1 - acrosome reaction.
- CS-1 - sperm-derived protein, causes initial zygote cleavage.
16. When does tolerance to auto-Ags develop in males?
- In the early stages of development and sperm cells are not formed until puberty. Thus, spermspecific Ags are not recognized as "self" by the adult immune system-> an immune response can
be generated against them.
17. When does ASA binding to sperm occur?
- Only after ejaculation.
18. Blood-testis barrier?
- Isolates sperm antigens from blood.
- Prevents anti-sperm Abs from entering testes.
19. What are the causes and what is asthenospermia?
- Reduced sperm motility or progression.
Causes:
- antisperm antibodies (breach of blood-testis barrier)
- immotile cilia
- leucocytospermia (infection/inflammation)
- prolonged abstinence
20. What is the Huhner test?
- A post-coital test done to examine the cervical mucus to see if it is "hostile" to sperm.
21. For a patient undergoing the Huhner test, instructions should the nurse give the patient?
- Have intercourse during estimated time of ovulation and be present for the test within 2-8 hours
after intercourse.