Use of Normal Mouse Serum to Detect Indirect Plaque-Forming Cells

Abstract

Abstract The introduction of a plaque technique for the identification and enumeration of cells synthesizing antibodies capable of lysing erythrocytes marked a major technical advance in immunology (1). The potential of the technique was significantly expanded by the introduction of antiglobulin reagents which permit the detection of additional plaque-forming cells (PFC)2 thought to be synthesizing 7S immunoglobulins (2, 3). However, the precise nature of these so-called indirect plaques was established only with considerable difficulty owing in large part to the problem of preparing anti-heavy chain sera of sufficiently high specificity. Indeed, only a fraction of the available antiglobulin reagents is completely suitable for the positive identification of IgG PFC, and those that have proven useful are reliable only at optimal concentrations that must be determined for individual sera. Of special concern in the selection of antisera is their tendency to inhibit the development of IgM plaques, a phenomenon which is observed frequently even with optimal dilutions of the reagents (3).