A Modified Flow Microcalorimeter Adapted for the Study of Human Leucocyte Phagocytosis

Abstract

A modified flow microcalorimeter is described, in which the sample fluid that passes through the instrument is in contact only with Teflon®. The heat production (H.P.) from samples with leucocytes and thrombocytes in heparin-dextran-plasma was determined and found to agree with earlier findings using a similar system with gold tubings. A substantial increase of H.P. was found when the leucocytes were phagocytizing certain bacteria or polystyrene latex particles. The increase was related to the number of particles added. When leucocytes were prepared from defibrinated serum, they had no or only very little H.P., although they retained their capacity for phagocytosis, and when stimulated, showed similar H.P. as leucocytes prepared in heparinplasma. It is suggested that the low H.P. corresponds to a resting condition of the leucocytes, and that it was observed because the measurements were made with minimal mechanical disturbance of the cells.

Key Words:

• Calorimetry
• leucocyte metabolism
• phagocytosis