Forssman

Forssman antigen is a heterophile antigen, meaning an antigen that is present in more than one species. It is a glycolipid, a lipid with a carbohydrate attached.

Forssman antigen is found on the surface of cells in a variety of animals, including guinea pigs, sheep, horses, dogs, and cats, as well as in some bacteria and parasites. However, it is absent in humans, rabbits, rats, and mice, with some exceptions dependent on tissue type. Its presence and distribution vary widely.

The presence or absence of Forssman antigen is a key factor in certain immunological reactions, particularly in the production of heterophile antibodies. Heterophile antibodies are antibodies that react with antigens from different species. In the case of Forssman antigen, individuals lacking the antigen (such as humans) can produce antibodies against it if exposed to cells or substances containing it.

The clinical significance of Forssman antigen and its associated antibodies lies in their potential to interfere with diagnostic tests or to cause pathological reactions in certain situations. For example, the presence of Forssman antibodies can complicate the interpretation of serological tests.