Cells binding the antigen keyhole limpet haemocyanin in the peripheral blood and in the lymphocyte cultures of non-immune and immunized human subjects.

Abstract

Cells binding the antigen Keyhole limpet haemocyanin (KLH) were detected among human peripheral blood leucocytes and antigen-stimulated cultured lymphocytes. They were detected by their formation of rosettes with antigen-coated human O red blood cells. In the peripheral blood 0·13% of the lymphocytes of non-immune and 0·80% of the lymphocytes of immune subjects were antigen binding. In KLH-stimulated cultures of the lymphocytes of non-immune subjects there were 0·1% antigen-binding cells and in those of immune subjects there were 8·5% antigen-binding cells. Binding was specific. Thus, lymphocytes from phytohaemagglutinin- and streptolysin O-stimulated cultures did not bind KLH-coated red blood cells and did not form rosettes with KLH-stimulated lymphocytes. Incubation of KLH-stimulated lymphocytes with heterologous anti-immunoglobulin serum revealed that the KLH receptor was related to IgM. Addition of metabolic blocking agents (puromycin, cycloheximide, actinomycin-D and arabinosyl cytosine) to KLH-stimulated lymphocyte cultures revealed that the generation of antigen-binding cells required both DNA and protein synthesis. After primary immunization of normal human subjects, antigen-binding cells were detected in their appropriate lymphocyte cultures at 7 days and reached their maximum level at 21 days, in five of the six kinetically followed individuals and at 14 days in the other. This data represents the first report of the generation of antigen-binding cells in lymphocyte cultures demonstrated by the rosette method. These methods should be useful in the study of a variety of immunological problems in man.