Veterinary Topics: Recognize, remember, and respond

Transfer factor could be link to using body’s own defense system to promote better health
by Kenneth L. Marcella, D.V.M.

THERE always seems to be one yearling that just does not do as well as his pasture mates. In the same environment as all the others, with the same amount and types of stress, he is the one who gets the respiratory infection. Or he has the worst and most persistent skin irritations when others have just a few scales and scabs that quickly heal.

Consider the broodmare that becomes pregnant each year but always develops a uterine infection that takes a lot of time and trouble to clear up. She and the yearling are most likely to have immune systems that are weaker than average and that are affected by viruses, bacteria, and other potentially damaging agents that would not trouble a normal horse.

Why resistance occurs

Immunotherapy is the field of medicine that deals with the immune system and tries to use the normal body defense mechanism to treat and prevent diseases, while seeking to help sensitive or weaker horses respond as would a normal individual. Immunotherapy was predicted to be one of the most rapidly expanding areas of science in the past decade, and great advances were expected. Through our ability to manipulate the body’s immune system, we were going to make people and animals healthier and increase the quality and length of life.

Also expected were immune-mediated advances that would make doctors less reliant on antibiotics. Over the years, through misuse and overuse of antibiotics, and the simple development of genetic resistance, many types of pathogenic (disease-causing) bacteria have become immune to antibiotics that were able to kill them less than ten to 20 years ago. Antibiotic-resistant staphylococcus organisms are a particular problem in humans, which is complicating everything from simple skin infections to organ transplants.

Veterinary medicine has fared somewhat better because many simple antibiotics (such as penicillin) still work reasonably well in animals, but it is only a matter of time before resistance starts to affect horses. Through immunotherapy, veterinarians would prescribe an immune stimulant and let these pumped-up body defenses do the rest. This method of manipulating the body was expected to provide better health for patients, while it decreased the potential for the development of antibiotic resistance.

Unfortunately, these miracle immune agents have not appeared. A few products help the body deal with infection and stress but not at the level that was expected. Until now.

Passed on immunity

Transfer factor is a newly released immune agent that could be the long-awaited miracle link to using the body’s own defense system to promote better health. "It is our ability to create a really healthy immune system that I think represents the greatest potential gains in health in the world," said Richard Bennett, Ph.D., an infectious disease immunologist from California.

The immune system provides humans and animals with the ability to recognize, remember, and respond to potentially harmful agents. Through different parts of the immune system (see sidebar), a horse can produce antigen against an invading virus, can use white blood cells to fight off a bacterial cold, or can even use specialized tissue cells to kill molds, fungi, and even some cancer types.

In 1949, Dr. H. Sherwood Lawrence, a researcher working on tuberculosis, found he could transfer immunity between patients using components of white blood cells, the body’s first line of defense against disease and a major component of the immune system. Lawrence found the key element in this passed-on immunity was part of the lymphocyte cell; he called this component "transfer factor."

This discovery was not actively pursued, however, until the late 1980s. At that time, colostrum (the first nursing milk produced by humans and animals) was discovered to contain significant amounts of transfer factor. It had been well established that breast-fed infants were healthier than infants fed a nutritionally complete synthetic formula. The importance of absorption of adequate colostrum by foals had been universally accepted. Researchers put these facts together and postulated that the transfer factor in colostrum potentially stimulated the immune systems of young humans and animals, and the transferred immune protection made these infants healthier.

The exact mechanism of action of transfer factor has yet to be established, but it is known that the molecule is a lymphokine. The two most well-known lymphokines are interferon and interleukin--both potent immune agents. These lymphokines are protein messengers and, while they do not kill bacteria or hunt down viruses, they are whistle-blowers for the entire immune system. They play a role in activating and mobilizing antibodies and in stimulating the process by which more immune cells are produced. Transfer factor is the most potent messenger found to date, and it has three distinct effects on the immune system.

Effects on immune system

Transfer factor helps the body recognize antigens. Molly Metz, D.V.M., a consultant for 4Life Research, the company that holds the patent for extracting transfer factor from its most available source, cow colostrum, points out that 200 milligrams of transfer factor has the potential for recognizing hundreds of pathogens. Metz adds that not only can transfer factor be specific for an individual bacterium or virus to which the animal producing the colostrum has been exposed, but it also can stimulate a multivalent response.

In this type of response, transfer factor activates lymphocytes against several strains of bacteria or several types of viruses all from a single initial message. "This is the really exciting part of immunotherapy in general and of transfer factor specifically from a practicing veterinary standpoint," said Metz.

4Life Research has found that, by exposing cattle to various bacteria and viruses, the animals can produce transfer factor that will stimulate immunity to other related strains of bacteria and viruses that are much more damaging to other species. Transfer factor is not species-specific, so lymphokines produced in cattle are capable of stimulating equally well equine or human immune systems.

"The other really exciting aspect of transfer factor," said Metz, "is the time sequence." Most types of antibody protection, such as that seen with vaccine use, take ten to 14 days to develop optimally. "Transfer factor," according to Metz and substantiated by research, "activated that same immunity in 24 hours."

If transfer factor can produce such boosts in 24 hours, then its use as a pre-travel protectant, heavy training protectant, or post-exposure treatment is tremendous.

Racehorses, who are prone to travel stress and exposure to viruses and bacteria, should be vaccinated on a regular schedule. Transfer factor allows for more rapid production and can be used well before race-day medication rules come into play. A horse, for example, could be given transfer factor on Monday through Thursday and legally race on Saturday.

What else it does

Transfer factor also carries out other important functions:

Natural killer-cell inductor. Natural killer cells are nonspecific cells that seek out and destroy infected or diseased cells and cells invaded by viruses. Transfer factor increases natural killer-cell activity 250% and is nonspecies specific.

It is believed that this aspect of transfer factor is related to the significant improvements seen in certain cancer patients that have used it.

Suppressor of immune function. It is paradoxical that the same product can both stimulate and suppress immune function, but the proper function of the immune system relates to the specific signals it is given.

Transfer factor can stimulate the release of antigens in response to a viral challenge or it can stimulate the release of T-suppressor cells when the immune system overreacts. Autoimmune diseases, chronic obstructive pulmonary disease (COPD or heaves), and various allergic reactions are all situations where the body’s immune system has overreacted to antigenic stimulation. Transfer factor works in these situations because it can slow down this overactive response.

Reduced use of antibiotics

While discussions of the immune system tend to be fairly technical, the practical advantages of a potent new immune stimulant such as transfer factor are clear. The ability to stimulate the horse’s own body to attack and destroy bacteria and viruses will reduce the amounts and types of antibiotics that may need to be used by veterinarians.

It is crucial to retain antibiotics that are still functional for veterinarians and to use them in a way that will maintain their effectiveness for as long as possible.

Horses suffering from such chronic diseases as Cushing’s syndrome, laminitis, colitis, and cancers ranging from sarcoids to melanomas also may benefit. Chronic reproductive infections may benefit from this type of immune boost. Because the immune system seeks to heal the body from within and to make it more resistant from attack from without, any immune improvement means better health in general. This is the long-awaited promise from the field of immunotherapy and perhaps transfer factor will finally deliver.

THE BODY has two principal immune defense systems: humoral (through the blood) and cellular (specialized cells in body tissue).

Specialized cells in the liver, spleen, lymph nodes, and bone marrow produce cells that, in turn, produce antibodies. These cells are exposed to a potentially damaging agent, such as a virus, which they recognize as not part of the body and potentially irritating to the horse. Recognition is important because some viruses seek to enter the body and cause problems by hiding in normal cells or by using other techniques to keep the body from being alerted to their presence.

Once the foreign particle is recognized, the immune system is programmed to remember what type of problem this specific invader can cause and which specific antibodies are necessary to fight it. Exposure to damaging agents (pathogens) begins to occur soon after birth. Humans and animals catalog these pathogens for later reference.

Immunoglobulins (specific antibodies) potentially can recognize huge numbers of antigens when the body releases them into the bloodstream in response to a medical threat. This is the basis of the humoral response.

Other cells called lymphocytes are responsible for cellular-based immunity. These cells produce lymphokines that control hypersensitivity or allergic reactions. These lymphokines also are responsible for the rejection of transferred foreign tissue and the recognition and rejection of tumor cells. Together, the humoral and cellular portions of the immune system seek to keep the body free of infectious agents and invading unwanted cells.

--Kenneth L. Marcella, D.V.M