Crossed radio-immunoisoelectric focusing as a method of identifying isoallergens: Identification of isoallergens in rat urine extracts

A method of 2-dimensional radio-immunoelectrophoresis to detect directly the presence of ‘isoallergens’ in complex allergenic (skin test) extracts is described. This procedure, in which the components are separated by isoelectric focusing in agarose gel in the first dimension is therefore basically similar to that of crossed radio-immunoelectrophoresis, and hence has been termed crossed radio-immunoisoelectric focusing. The method has been applied to the allergens present in rat urine and has verified the presence of the cross-reacting α 2-euglobulin and prealbumin components in (at least) 3 and 2 isoallergenic forms respectively.