Leukotoxins

LEUKOTOXINS are formed in the serum of an animal as a result of immunization with leukocytes and belong to cytotoxins, i.e., cellular poisons. L. are at the same time leukolysins, since under the influence of serum possessing leukotoxic properties, leukocytes are not only killed but also dissolved. Similar to hemolytic effect, the leukotoxic effect of serum represents the result of the combined action of two substances present in the immune serum (resp. two properties of such serum): amboceptor and complement. L. possess specificity, i.e., they dissolve only those leukocytes with which immunization was performed. Leukocidin is a substance produced by staphylococci as well as streptococci (streptoleukocidin); first discovered by Van de Velde in the pleural exudate of rabbits infected with staphylococcus; it is also contained in cultures of old staphylococcus and streptococcus; under the influence of leukocidin, leukocytes die and then undergo dissolution. The ability to produce leukocidin corresponds to the degree of virulence of the culture. When immunizing animals with staphylococcus, their serum acquires the ability to neutralize in vitro the leukocidin produced by staphylococcus (immun-leukocidins).