FOOD ALLERGY: ALLERGEN AND ADJUVANTS

Posted by admin on April 20, 2009 under Allergies | Be the First to Comment

An allergen is essentially the same thing as an antigen, except that it happens to cause an allergic reaction in a particular person. The proteins in cow’s milk, for example, are antigens to most of us, but for the child with cow’s-milk allergy they are allergens. The main difference between an antigen and an allergen is not in the molecule itself but in the way the individual’s immune system reacts to it.

Having said that, it does seem that some foods are more ‘allergenic’ – more likely to cause allergies – than others. Certain foods turn up again and again as the culprits in food allergy, while other commonly eaten foods are rarely en-

countered. Why this is so, no-one can say at present, but there are several possible explanations.

Perhaps these apparently more allergenic foods contain compounds with very unusual and distinctive chemical features that are ‘easily recognized’. Such compounds might induce IgE antibodies more readily than others, although it is far from certain that the structure of antigens can exert such an influence over the immune system. The whole question of how the body scrutinizes incoming antigens and regulates its response to them is still very poorly understood. As yet no-one can say what role the chemical make-up of antigens plays.

An alternative explanation is that such foods contain substances which stimulate an immune response, known collectively as adjuvants. Adjuvants are used in the laboratory as a way of inducing immune responses for research purposes. These adjuvants are mostly derived from bacteria, but there are also adjuvants found in some plants. The extent to which these occur in foods, and their potential for stimulating IgE rather than other types of antibody, is unknown.

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