Plaque-forming cells in man. I. Basic technical results obtained with the protein A technique

Area of Science:

• Immunology
• Cell Biology

Background:

• Human peripheral blood lymphocytes (PBL) play a crucial role in adaptive immunity.
• Understanding T and B lymphocyte interactions is vital for dissecting immune responses.
• Pokeweed mitogen (PWM) is a common stimulant for lymphocyte activation and differentiation.

Purpose of the Study:

• To investigate the optimal T/B lymphocyte ratios for immunoglobulin production using an indirect protein A plaque-forming cell (PFC) assay.
• To compare the PFC response in unfractionated, reconstituted, and irradiated lymphocyte cultures.
• To assess the influence of sex and cell source (autologous vs. allogeneic) on lymphocyte responses.

Main Methods:

• Indirect protein A plaque-forming cell (PFC) assay was employed.
• Human peripheral blood lymphocytes (PBL) were activated with pokeweed mitogen (PWM).
• T and B lymphocytes were mixed at various ratios (1:8 to 8:1) and compared with unfractionated cells. Irradiated T lymphocytes were used to assess T-cell dependency.

Main Results:

• Maximal immunoglobulin (Ig) response was achieved after 6 days of culture.
• Optimal PFC response for untreated T/B lymphocytes occurred at a 1:4 T/B ratio.
• Untreated B cells with irradiated T cells showed maximal response at a 4:1 T/B ratio, exceeding unfractionated cells but lower than reconstituted untreated cells.

Conclusions:

• Specific T/B lymphocyte ratios significantly influence the magnitude of the PFC response.
• T-cell help, even from irradiated cells, is crucial for optimal B-cell activation and Ig production.
• The PFC assay is a reliable method for quantifying B-cell activation and immunoglobulin class-specific antibody production in human PBL.