Plaque-Forming Cells in Man I. Basic Technical Results Obtained with the Protein A Technique.

This paper describes the results obtained using an indirect protein A plaque-forming-cell (PFC) assay applied to human peripheral blood lymphocytes (PBL) activated with pokeweed mitogen (PWM). A maximal-response was obtained after 6 days of culture with regard to the three major classes of immunoglobulin (Ig) investigated. No difference was found between females and males. T and B lymphocytes mixed in ratios varying from 1:8 to 8:1 and unfractionated cells were investigated. A maximal PFC response of isolated lymphocytes was found in cultures of 1:4 T/B reconstituted suspensions of untreated cells, whereas the maximal response of untreated B and 2000-rad-irradialed T lymphocytes was found in cultures with a 4:1 T/B ratio. The number of plaques developed in cultures of unfractionated cells exceeded the response of 4:1 T/B reconstituted untreated lymphocytes but was far below the number of PFC developed in cultures of untreated B and 2000-rad-irradiated T lymphocytes. Normal donors developed approximately 70 × 10³ PFC/10⁶ cells. The viability was 85% alter the incubation period. No difference was found in the PFC response of cultures of separated, reconstituted T/B lymphocytes set up in autologous and allogeneic combinations. [ABSTRACT FROM AUTHOR]