Human leucocyte responses in vitro. I. Transformation of purified T lymphocytes with and without addition of partially purified monocytes

Abstract

Highly purified Fc receptor-negative T lymphocytes were obtained by filtration of human blood mononuclear cells through Ig–anti-Ig columns. Monocyte-enriched cells were isolated by density centrifugation in bovine serum albumin solutions. The proliferative in vitro response of the purified T lymphocytes was investigated with and without the addition of monocyte-enriched cells, after stimulation by allogeneic cells, phytohaemagglutinin (PHA), pokeweed mitogen (PWM), purified protein derivative (PPD), Candida albicans, Staphylococcus aureus, E. coli and tetanus toxoid.

The results were as follows:

(1) Fc receptor-negative T lymphocytes respond autonomously, and are the main source of proliferative cells found after stimulation by allogeneic cells and optimal doses of PHA, PWM and PPD. Addition of monocyte-enriched cells increases the responses, presumably by a non-specific feeder-effect in the cultures.

(2) Stimulation of Fc receptor-negative T lymphocytes by C. albicans, S. aureus, E. coli and tetanus toxoid requires the presence of autologous monocytes in the cultures, whereas allogeneic monocytes do not support the responses.

(3) Fc receptor-negative T lymphocytes are the main proliferating cells found after stimulation by C. albicans, whereas other cells (B-lymphocytes and/or Fc receptor-positive T lymphocytes) may be responsible for a substantial part of the proliferation elicited by S. aureus, E. coli and tetanus toxoid.

(4) Fc receptor-negative T lymphocytes can stimulate allogeneic cells in mixed lymphocyte culture, but monocyte-enriched cells and unfractionated mononuclear cells are better in this respect.