Leukocidin - a substance produced by Staphylococcus; toxic effect on cells. The ability to develop leukocidin depends on virulence of culture.
There are three types of leukocidin: first acts on leukocytes rabbit; the second has a toxic effect on leukocytes rabbit and person and is not valid for leukocytes Guinea pigs, mice and sheep; the third has a negative effect on the leucocytes of man, rabbit, Guinea pigs and mice, not active against the leukocyte count sheep. The toxic effects of various types L. varies from minor damage to morph, structures of leukocyte to complete lysis of white blood cells. Killed L. leukocytes lose the ability to recover (discolor) methylene blue. Based on this "biocapacity" method of determining L. Pathogenic staphylococci produce leukocidin with titers ranging from 1 : 200 to 1 : 1000 ("bioskopima" method). Serum of animals immunized with staphylococci aureus, acquires the ability in vitro to neutralize L.
Cm. also Staphylococci.