Transfer factors are immune molecules that cause antigen

Antigen

An antigen is a foreign molecule that, when introduced into the body, triggers the production of an antibody by the immune system. The immune system will then kill or neutralize the antigen that is recognized as a foreign and potentially harmful invader. These invaders can be molecules such as...

-specific cell-mediated immunity

Cell-mediated immunity

Cell-mediated immunity is an immune response that does not involve antibodies but rather involves the activation of macrophages, natural killer cells , antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen...

, primarily delayed hypersensitivity and the production of lymphokine

Lymphokine

Lymphokines are a subset of cytokines that are produced by a type of immune cell known as a lymphocyte. They are protein mediators typically produced by T cells to direct the immune system response by signalling between its cells...

s, as well as binding to the antigens themselves. They have a molecular weight of approximately 5000 Daltons

Atomic mass unit

The unified atomic mass unit or dalton is a unit that is used for indicating mass on an atomic or molecular scale. It is defined as one twelfth of the rest mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state, and has a value of...

 and are composed entirely of amino acid

Amino acid

Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...

s. Transfer factors were discovered by Henry Sherwood Lawrence. They are promoted as being able to cure a variety of conditions, though they have not been proven to work.

Uses

Transfer factors have been promoted as a treatment for a large number of diseases and health concerns but have not been proven effective in the treatment of most of these conditions. It may help immunize

Immunization

Immunization, or immunisation, is the process by which an individual's immune system becomes fortified against an agent ....

 children with leukemia

Leukemia

Leukemia or leukaemia is a type of cancer of the blood or bone marrow characterized by an abnormal increase of immature white blood cells called "blasts". Leukemia is a broad term covering a spectrum of diseases...

 against shingles

Herpes zoster

Herpes zoster , commonly known as shingles and also known as zona, is a viral disease characterized by a painful skin rash with blisters in a limited area on one side of the body, often in a stripe...

. The United States Food and Drug Administration regulates transfer factors as a dietary supplement and has issued a warning notice

FDA Warning Letter

The United States Food and Drug Adminstration defines a Warning Letter as "...a correspondence that notifies regulated industry about violations that FDA has documented during its inspections or investigations...

 to a website selling transfer factors that they have not been proven to be effective or safe in the treatment of any condition, nor have there been any biological licenses or New Drug Application

New drug application

The New Drug Application is the vehicle in the United States through which drug sponsors formally propose that the Food and Drug Administration approve a new pharmaceutical for sale and marketing...

s produced for the substance.

Side effects

Human-derived transfer factor appears to be safe for use (though ineffective) for up to two years and bovine-derived transfer factor for up to three months. Side effects include fever

Fever

Fever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in...

 and swelling and pain at the injection site. Concern has been raised over the possibility of catching Bovine spongiform encephalopathy

Bovine spongiform encephalopathy

Bovine spongiform encephalopathy , commonly known as mad-cow disease, is a fatal neurodegenerative disease in cattle that causes a spongy degeneration in the brain and spinal cord. BSE has a long incubation period, about 30 months to 8 years, usually affecting adult cattle at a peak age onset of...

(Mad Cow Disease) or other diseases from animal-derived products. Transfer factors are contraindicated for women who are pregnant or breastfeeding.