P. Saragueta et al., IMMUNOGLOBULINS FROM HUMAN FOLLICULAR-FLUID INDUCE THE ACROSOME REACTION IN HUMAN SPERM, Molecular reproduction and development, 39(3), 1994, pp. 280-288
The ability of human follicular fluid (hFF), retrieved from women unde
rgoing IVF to induce the acrosome reaction (AR) in human sperm has bee
n documented by several laboratories. However, the nature of the activ
e factors in the hFF and the physiological meaning of the AR induction
are highly controversial. We performed a three step purification sche
me for hFF and all the fractions were screened for the AR-inducing act
ivity. AR activity was associated with a protein fraction of M(r) > 18
0 kD that on further analysis under PAGE was found to be composed by s
ubunits of apparent M(r) 50,000 and 29,000. The N-terminal sequences o
f these bands showed a 100% homology with the heavy and light chains o
f human IgG. A polyclonal antibody raised against the purified protein
and anti-human IgG were both able to suppress the acrosome reaction-i
nducing activity of crude hFF. However, neither normal human serum nor
a purified preparation of human IgG were able to mimic the AR-inducin
g activity of hFF. We concluded that the AR-inducing activity of hFF i
s, at least in part, due to the presence of antisperm antibodies. (C)
1994 Wiley-Liss, Inc.