Synthesis of antibody and immunoglobulins without detectable antibody function in cells responding to horseradish peroxidase.

The kinetics of immunoglobulin-synthesizing cells (IFC) and antibody-forming cells (AFC) are compared in the popliteal nodes of mice challenged, in the hind footpads, with horseradish peroxidase (PO) in Freund's complete adjuvant. A rise in the number of IFC without antibody function precedes the appearance of AFC. IFC reach peak numbers 7 days before AFC. Control experiments show that the majority of IFC without antibody function are responding to PO and not to adjuvant. Kinetic and radioautographic data suggest that IFC arise by division and differentiation; however, the doubling time of AFC is too rapid to be accounted for by cell division alone. Double staining techniques revealed the presence of immunoglobulin and antibody in different compartments of the same cell in 5 to 15% of the AFC. It is postulated that some AFC are recruited, possibly from cells already synthesizing immunoglobulin determinants.