Evaluation of phagocytic and bactericidal activities of neutrophil granulocytes. Determination of viable extracellular bacteria by their incorporation of 14C-leucine and 3H-thymidine.

A method for evaluation of human neutrophil granulocyte function based on the combined determination of total and extracellular bacteria is described. The total number of surviving bacteria is assessed by the determination of colony forming units (CFU) after hypotonic lysis of granulocytes. Extracellular viable bacteria can be determined by the incorporation of 14C-leucine or 3H-thymidine into bacterial macromolecules since there is a linear relationship between macromolecular synthesis and bacterial number and insignificant amounts of both 14C-leucine and 3H-thymidine is taken up by intracellular viable organisms. This method might be suitable for the differentiation of defects in phagocytosis and intracellular killing of various bacteria.