The use of filter paper chromatograms to demonstrate antigen-antibody reactions.

The interaction of antigen and antibody in vitro is customarily conducted in a liquid or semiliquid environment. Demonstrable reactions may occur in the form of different serological phenomena depending largely on the physicochemical forces involved and the circumstances surrounding the admixture of antigen and antibody. The use of filter paper by Castaneda (1950) to demonstrate the presence of a Brucella antigenantibody system introduced a technique in which paper and not a serological test tube constituted the milieu in which the reaction took place. The technique featured the use of a stained Brucella antigen placed on the surface of filter paper which was observed to resist the washing effect of a stream of isotonic saline in the presence of Brucella immune serum. The phenomenon which took place in less than one minute was called "surface fixation" and was not observed to occur in the presence of normal or heterologous immune serum. The observations made were confined to the demonstration of this interaction between Brucella antigen and antibody. The present study was designed primarily to explore the capacity of stained antigens prepared from known pathogenic strains of bacteria to facilitate by means of paper chromatograms the detection and measurement of in vitro agglutinin reactivity. A second consideration concerned the possible extension of the technique to a practical role in diagnostic bacteriology.