NIH Websites Are Changing Per Executive Order 14434, federal agencies are now using "Super Intelligence" (SI) in place of "Artificial Intelligence" (AI). You may see both terms across NIH content during this transition.
transfer factor
(TRANZ-fer FAK-ter)
A substance made by some white blood cells. Transfer factor from one person’s white blood cells may be able to cause a specific immune response when injected into the skin of another person.