Solid-phase radioimmunoassay for detection of plague antigen in animal tissue.

A rapid and sensitive radioimmunoassay for the detection of soluble Yersinia pestis fraction I antigen using antibody-coated beads and radiolabeled immunoglobulin was applied to spleen-liver extracts, rendered noninfectious by either treatment or filtration, from rodents dead of plague. The procedure was capable of detecting nanogram amounts of soluble plague antigen.