Wh. Kutteh et al., ANTISPERM ANTIBODIES (ASAS) IN INFERTILE MALES - SUBCLASS DISTRIBUTION OF IGA ANTIBODIES AND THE EFFECT OF AN IGA1 PROTEASE ON SPERM-BOUND ANTIBODIES, American journal of reproductive immunology [1989], 31(2-3), 1994, pp. 77-83
PROBLEM: (1) To determine the IgA subclass distribution of antibodies
in the serum and on the sperm of infertile male patients. (2) To deter
mine the effect of an IgA1 protease on the binding of IgA antisperm an
tibodies (ASA). METHOD: Fifteen infertile males with ASA in serum (10)
or on sperm (5) were recruited for this study. Duration of infertilit
y was at least one year. Monoclonal antibodies to human IgA1 and IgA2
were conjugated to immunobeads. The distribution of IgA1 and IgA2 subc
lass ASA was determined for positive serum and sperm samples. The effe
cts of an IgA1 protease (isolated from Neisseria meningitidis strain H
F13) on sperm-bound antibodies was evaluated by immunobead binding. RE
SULTS: In serum, the IgA1 subclass ASA was predominate (91%) when comp
ared with IgA2 (9%) subclass. Direct sperm-bound antibodies displayed
a distribution more characteristic of the secretory immune system with
IgA1 accounting for 63% and IgA2 accounting for 37% of the total IgA
ASA. Enzyme treatment dramatically reduced the amount of serum IgA ant
ibodies bound to sperm (P < 0.05). Similarly, a significant reduction
in direct sperm-bound antibodies was observed after enzymatic treatmen
t with no loss in sperm motility. CONCLUSIONS: (1) Although IgA1 direc
t sperm-bound antibodies were dominant, when compared with serum there
was a higher proportion of IgA2 subclass, which suggests a local prod
uction of IgA. (2) Specific IgA1 protease treatment is capable of redu
cing the amount of immunobead-detectable IgA on sperm. Hamster oocyte
sperm-penetration assays are ongoing to determine if this treatment mi
ght improve sperm penetration rates.