Monocyte chemotaxis: a method for routine in vitro investigation using lactic dehydrogenase as a marker enzyme

Using the cytoplasmic enzyme lactic dehydrogenase (LDH) as a marker, a method for routine measurements of highly purified monocyte chemotaxis is described. Standardization of this assay was carried out in order to achieve objective and reproducible results. The LDH-method showed a good correlation with both the 51Cr-chemotactic assay and the leading-front technique. The sensitivity of the LDH-method could be compared with the 51Cr-assay and was significantly higher compared to the leading-front technique. Being objective, inexpensive and requiring only a photometer as equipment, the LDH-method was proved to be suitable for routine investigations of monocyte chemotaxis as a part of monocyte functional activity in laboratories engaged in leukocyte research.