Immunoperoxidase detection of immunoglobulins in cells of immunoproliferative diseases. A comparison between conjugate and nonconjugate (PAP) procedures.

Two immunoperoxidase procedures, direct conjugate and peroxidase-antiperoxidase (PAP) nonconjugate, were compared by studying surface and cytoplasmic immunoglobulins in identical smeared or embedded material from patients having various conditions involving B-cell proliferation. The direct procedure was carried out with affinity-purified antibodies; the PAP procedure was carried out with commercially available antisera and in some experiments by also using purified antibodies as a primary layer. This study confirms the feasibility of both procedures for staining human B cells, although surface immunoglobulins were not visualized in tissue sections. By comparing the phenotypes obtained with both procedures, this study also emphasizes the need for highly specific reagents and the possible shortcoming represented by contaminating specificities present in the first serum layer of the PAP procedure. Diluting primary antiserum was effective in eliminating such unwanted specificities, but at the same time could alter the genuine phenotype of cells. This study emphasizes the need for highly specific reagents such as solid-phase immunoadsorbed antibodies.