Factor derived from leukocyte lysates of immune donors which can transfer both local and systemic cellular immunity to nonimmune recipients.
Low-molecular-weight chemicals extracted from immune cells activated to respond to specific antigens. These products can be taken from a sensitized person and given to another. As a result of this transfer, the recipient will react to the same antigen originally used to sensitize the lymphocytes of the donor. In humans, the factor can be transferred by injecting the recipient with either intact lymphocytes or extracts of disrupted cells. It has been studied as adjunctive therapy used to modulate the immune system in several clinical trials.