Epitope selection to male specific antigens for sex selection in swine

Immunological approaches to gender selection have been contemplated since the discovery of the family of male-specific H-Y antigens found only on the surface of male cells. H-Y antigens are able to elicit an immune reaction when cells or tissues from a male donor are grafted to a female recipient. We describe here the development and testing of an inexpensive approach using polyclonal antibodies against four specific H-Y outer membrane proteins male enhanced antigen 1 (MEA 1), male enhanced antigen 2 (MEA 2), sex determining region Y (SRY) and testis determining factor (TDF). Epitopes based on hydrophilic primary sequences of the proteins were synthesized, N-terminal biotin-labeled, linked to streptavidin and mixed with a Ribi adjuvant prior to immunization in rabbits. The antiserum was tested to determine affinity to swine spermatozoa using anti-motility, flow cytometry and motility and sedimentation chambers. Fluorescent microscopy and fluorescent in situ hybridization (FISH) was used to identify the percentage of motile spermatozoa that contained the Y chromosome. We found that the polyclonal antibodies had high affinity to the spermatozoa leading to a cessation of motility. Furthermore, the majority of these non-motile spermatozoa contained the Y chromosome. We conclude that the use of polyclonal antiserum against synthetic H-Y peptide antigens may be an inexpensive and simple means to inhibit the motility of swine spermatozoa bearing the Y chromosome.