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) induce d specifically the acrosome reaction (AR) in human spermatozoa, Our ob jective was to investigate the relationship between this phenomenon an d the in-vitro fertilization (IVF) rate, Sperm suspensions from IVF pr otocols were incubated with BSA-GlcNAc (t), using calcium ionophore (i ) or medium alone (c) as positive or negative controls, When the norma lized AR percentage ratio (STIM) (%ARt-%ARc): (%ARi-%ARc) was compared with fertilization rate in 31 couples from our IVF programme, a posit ive 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 ov erall predictive value of this test for adequate fertilization rate ( > 30%) was 87%, sensitivity 91% and specificity 78%, False positives w ere 9% and false negatives 22%, For successful fertilization rates ( > 60%), the results were: overall predictive value, 84%; sensitivity 10 0%; specificity 64%, False positives were 23% and no false negatives w ere found. The results indicated that the induction of AR in human spe rmatozoa by GlcNAc-neoglycoproteins could be used to predict their fer tilizing ability in vitro.