Identification and characterization of a sperm peptide antigen recognized by a monoclonal antisperm autoantibody derived from a vasectomized mouse

A monoclonal autoantibody (MAb) to mouse sperm was established from a vasectomized mouse. The MAb, termed 4A11, reacted exclusively to mouse and rat live sperm tail, without any cross-reaction with sperm of other mammalian species or any somatic organ tissues in the mouse. MAb 4A11 significantly inhibited in vitro fertilization of mouse ova. Western blotting showed a single band of 67 kDa as the corresponding antigen protein of MAb 4A11. By screening a mouse testis cDNA library with MAb 4A11, one positive clone (964bp) was obtained. DNA sequence of the clone showed no homology with any previously reported mammalian genes, but showed 54% homology with a bacterial gene of sucrose-specific phosphotransferase enzyme II. The rabbit antisera raised to the recombinant protein of the 4A11 cDNA gene showed reaction to mouse, rat, hamster and guinea-pig sperm.