SPERM-ASSOCIATED AND CIRCULATING IGA AND IGG CLASSES OF ANTIBODIES RECOGNIZE DIFFERENT ANTIGENS ON THE HUMAN SPERM PLASMA-MEMBRANE

IgA and IgG antibodies eluted from the surface of spermatozoa obtained from 11 infertile men were used to analyse the antigens defined by ea ch class of sperm-associated antibodies. An enhanced chemiluminescent Western blot technique was developed to detect the low concentrations of immunoglobulins present in the eluted samples. The same analysis wa s performed with the sperm membrane-specific antibodies isolated from the sera of 8 of the patients included in the study. Sperm-eluted anti bodies reacted with a total of 18 protein bands migrating with molecul ar masses of between 110 and 18 kDa. Individual antibody-binding patte rns differed. Furthermore, IgA and IgG antibodies from any one patient recognised different sets of antigens. In spite of the apparent heter ogeneity of the antigens defined by sperm-associated antibodies, the m ajority of these antibodies reacted with three protein zones of 68/64, 37/36 and 20/18 kDa. The antigens defined by the sperm surface-specif ic antibodies obtained from the sera of eight infertile patients diffe red from one patient to another and, in the majority of the patients, differed from those defined by the corresponding sperm-associated anti bodies. Nevertheless, two protein zones of 68/64 and 20/18 kDa were re cognised by both local and systemic antibodies in 6 and 4 patients. re spectively. (C) 1997 Elsevier Science Ireland Ltd.