IMMUNO-REACTIVE REAGENT, MANUFACTURE THEREOF AND APPLICATION THEREOF FOR MEASURING IMMUNO-REACTIVE SPECY

摘要

A reagent useful in the determination of an immunoreactive species comprises water-insoluble particles having tracer molecules associated therewith. Bound to the outer surface of the particles are: (1) receptor molecules which are reactive with the species, and (ii) molecules of a protein having a pI less than about 6, and which protein is not reactive with either the species or the receptor molecules. The weight ratio of the receptor molecules to the low pI protein molecules is from about 100:1 to about 1:10. This reagent is useful in agglutination and other immunological reactions. A method of preparing the reagent includes providing a suspension of the particles and contacting them with the receptor molecules and low pI protein so as to attach both to the particles. The protein is present in the suspension in an amount such that substantially all of it is attached to the particles. The reagent thus prepared can be used, for example, in agglutination assays for the determination of a multivalent immunoreactive species, such as Streptococcus A antigen.