A NEW PREDICTIVE TEST FOR IN-VITRO FERTILIZATION BASED ON THE INDUCTION OF SPERM ACROSOME REACTION BY N-ACETYLGLUCOSAMINE-NEOGLYCOPROTEIN

Neoglycoproteins with N-acetylglucosamine residues (BSA-GlcNAc) induced specifically the acrosome reaction (AR) in human spermatozoa, Our objective was to investigate the relationship between this phenomenon and the in-vitro fertilization (IVF) rate, Sperm suspensions from IVF protocols were incubated with BSA-GlcNAc (t), using calcium ionophore (i) or medium alone (c) as positive or negative controls, When the normalized AR percentage ratio (STIM) (%ARt-%ARc): (%ARi-%ARc) was compared with fertilization rate in 31 couples from our IVF programme, a positive correlation was found (r = 0.46, P < 0.01), The fertilization rate in patients with STIM greater than or equal to 0.2 was higher than in non-responders (STIM < 0.2); 72 +/- 7% compared with 5 +/- 3%, The overall predictive value of this test for adequate fertilization rate ( > 30%) was 87%, sensitivity 91% and specificity 78%, False positives were 9% and false negatives 22%, For successful fertilization rates ( > 60%), the results were: overall predictive value, 84%; sensitivity 100%; specificity 64%, False positives were 23% and no false negatives were found. The results indicated that the induction of AR in human spermatozoa by GlcNAc-neoglycoproteins could be used to predict their fertilizing ability in vitro.