Specificity for tail fibers of a humoral crab factor neutralizing T2 bacteriophage

It is now becoming clear that invertebrates, animals lacking the ability to make humoral antibodies, are capable of recognizing self from non-self. In several instances this recognition is manifest in normal ("unimmunized") animals by a rapid clearance of certain foreign materials from the circulation One example of such a rapid innate reaction involves the clearance of T2 bacteriophage from the blue crab (1). Other studies have indicated that blue crab plasma contained a factor capable of neutralizing in vitro T2 bacteriophage and hence, by inference, was responsible for the in vivo clearance reaction with this virus (2). The purpose of the work undertaken here was to establish the nature of the specificity of this in vitro neutralizing factor. The strategy involved utilizing purified T2 bacteriophage tail fibers to inhibitthe neutralization of T2 bacteriophage by crab plasma.