Specificity in the recognition of crystals by antibodies.

We show that IgG molecules isolated from the serum of rabbits injected with crystals of monosodium urate monohydrate, magnesium urate octahydrate and allopurinol, can each catalyze the nucleation of the same type of crystal to which they were exposed. These results generalize previous findings related to monosodium urate monohydrate and assess the idea that the invasion of a foreign crystal into an organism may amplify a population of antibodies which bear in their binding sites an imprint of the crystal surface structure. Such antibodies can further act as nucleating templates which accelerate crystal formation in vitro. Antibodies isolated from rabbits injected with sodium urate crystals do not cross-react or cross-react only to a low extent with antibodies isolated from rabbits injected with crystals of either magnesium urate or allopurinol. These results indicate a high specificity of the elicited antibodies, as these can distinguish between nuclei of crystals having similar molecular and structural characteristics.