Neutrophil granulocyte function in vitro. Evaluation of a fluid-phase leucocyte-bacteria reaction system.

Abstract

A modified method for evaluation of human neutrophil granulocyte function in vitro, based upon the combined determination of total and intracellular surviving bacteria in a reaction system of leucocytes and Staphylococcus aureus, is described. Analysis of the system reveals a close relationship between the processes of ingestion and intraleucocytic killing on a functional level, and points towards dependence of intraleucocytic killing rate upon the rate of ingestion. Defects in intraleucocytic killing are disclosed readily by an increase in the number of surviving intracellular bacteria which will not be caused by increased ingestion under normal conditions. Greatly impaired ingestion will cause an increase in total surviving bacteria with a near normal number of intracellular surviving bacteria. On the basis of these studies it can be concluded that this type of method is particularly suitable for the detection of defects in intraleucocytic killing whereas defects in ingestion are less readily disclosed.