It is possible to develop antibodies to sperm. Almost always, sperm antibodies are generated by the man producing the sperm. Most commonly, sperm antibodies are generated after vasectomy. The areas of the testicles where sperm are formed, and the entire tract that delivers the sperm as ejaculate is immunologically isolated from the rest of the body. Proteins on the surface of sperm are never in contact with the body to either be recognized as part of “self” or, under normal conditions, be deemed as foreign material. Performing a vasectomy interrupts the normal barrier between the portion of the body which produces sperm and conducts them to the exterior at the time of ejaculation. Once the barrier is breached, the body’s immune system discovers a new set of proteins, and believes them to be foreign invaders. Therefore, the immune system begins to make antibodies. Antibodies are large proteins which attach to sperm, and can interfere with motility or cover the head of the sperm, so as to interfere with the acrosome reaction.
To explain the last term, the sperm head is covered by a packet of enzymes called the acrosomal cap. As part of the process the sperm undergoes to be able to fertilize an egg, the outer membrane of the acrosomal cap breaks down, releasing the enzymes. Enzymes of the acrosomal cap change the membrane covering the sperm head behind the acrosomal cap allowing the sperm head membrane to fuse with an egg cell membrane. Once fusion of these 2 membranes occurs, the boundary between sperm head and egg disappears, and chromosomes of the sperm enter the egg to fertilize it. If the sperm head is covered by antibodies, none of these processes can occur.
Trauma to the male reproductive tract can also cause a defect in the barrier between the sperm production area and the immune system. Men are vulnerable to sports injuries. Occasionally, a testicle can twist on its blood supply. The result can be painful loss of a testicle, but even if the testicle can be saved, there is likely to be damage. Even less commonly, a testicle my not descend from the fetal abdominal cavity into the scrotum. In addition to the increased risk of developing an aggressive cancer, if not surgically corrected, there is potential for injury to the structure of the testicle.
How do we go about testing for antibodies? The really reliable test is a kit available to specialist in male fertility. It is the ImmunoBead® test. Antibodies to the 3 basic groups of human antibodies are coated on microscopic latex particles. A suspension of these latex particles are incubated with sperm form the male patient. If there are antibodies on the sperm, the latex particles are caused to clump together by antibodies to the antibodies on the sperm. This direct ImmunoBead® test is very sensitive and specific for antibodies made by a man to his own sperm.
Very rarely, a woman will make antibodies to her husband’s sperm. The cause of such circumstance is highly speculative. We really do not know the cause. There is a test for that. If a woman does have antibodies to sperm, those antibodies will be in circulation in her blood. If we incubate her serum with donor sperm that are known not to have antibodies, her antibodies will attach to the donor sperm. Now, we can perform an ImmunoBead® test to look for antibodies.
Problems with sperm antibodies can be overcome. By far, the most reliable way to do that is to use the technologies of in vitro fertilization (IVF). If we remove sperm and eggs to the laboratory, antibodies a woman may make to her husband’s sperm will not have a chance to attack the sperm. Just performing intrauterine insemination to bypass cervical mucus is not very reliable. Antibodies will be in her uterus and fallopian tubes, too. Much more commonly, the man has produced antibodies to his own sperm. In such a case, it will likely be necessary to really help the sperm by literally injecting them into the eggs. This process is called intra-cytoplasmic sperm injection or ICSI. ICSI is commonly performed today for a variety of male factor issues.
We have come a long way from the early days of the Franklin-Dukes test to try to identify problems related to antibodies to sperm. We have a much better understanding of the problems, and much improved means of treatment. Even so, many myths endure, often delaying meaningful management.
Dr. Jacobs is a Reproductive Endocrinologist, practicing in
Barry Jacobs, M.D., 4323 M. Josey Lane, Suite #201, Carrollton, TX 75010 www.texasfertility.com