A new technique for detecting the immediate precursor of the antigen reactive cell in mouse bone marrow

Abstract

A liquid culture system was developed which supports the production of anti-TNP plaque-forming cells from early precursor cells in the bone marrow of mice. In mouse bone marrow there exists a subpopulation of cells which can be triggered by a polyclonal activator (dextran sulfate) to differentiate into antigen reactive cells (ARC), which can then undergo oligoclonal expansion and maturation in the presence of a thymus independent antigen (TNP-LPS) to yield anti-TNP plaque-forming cells. Under optimal conditions 100–600 anti-TNP plaque-forming cells are obtained per 5 × 10 5 bone marrow cells plated. We refer to these as P-PFC, plaque-forming cells which arise from early precursor cells (pre-ARC) in the bone marrow. The use of hydroxyurea either in vivo or in vitro to destroy cycling cells and Ficoll-metrizoate continuous gradient density columns to obtain bone marrow small lymphocytes suggested that the progeny of cells detected in the P-PFC assay arose from resting small lymphocyte precursors.