ANTI-ENZYME IMMUNITY 267 



fibrinolytic factor. Le Mar and Gunderson (1940), testing the activity 

 of fibrinolytic factor of /?-liemolytic streptococci from human and veter- 

 inary strains (swine, dog, sheep, guinea pig, rabbit, fox, duck and 

 pigeon, bovine and horse) against their homologous fibrin and cross- 

 testing against each of the other fibrins, reported that the group of 

 streptococci of human origin was more actively lytic than any other, 

 attacking all fibrins to some degree. Lysis of human fibrin by strepto- 

 cocci, however, was most rapid and complete of all. Likewise, each 

 group of veterinary organisms attacked human fibrin more quickly and 

 dissolved it more completely than it did its own homologous fibrin. 

 Prolonged incubation (96 hours) of cultures enhanced the lytic power 

 of most of the strains of streptococci. Complete lysis of fibrin occurred 

 in 75 per cent of the tests in less than 30 minutes when 96 hour 

 cultures were used as source of fibrinolytic factors. 



Madison (1935) reported that of 132 strains of staphylococci, 80 

 per cent of all strains originally isolated from internal human lesions 

 were capable of liquefying human fibrin. Approximately 90 per cent 

 of all strains isolated from superficial human infections, however, 

 and all strains from veterinary lesions were inactive by the same 

 in vitro technique (see also Madison and Dart, 1936). Neter (1937) 

 reported that staphylococci from human sources may produce fibrino- 

 lytic factor dissolving human as well as animal plasma clots. Of 43 

 strains of hemolytic Sta'phylococcus aureus six produced the fibrino- 

 lytic factor. On the other hand, of 10 strains of non-hemolytic staph- 

 ylococci none produced the factor. Staphylococcal factor was specifi- 

 cally neutralized by staphylococcus antiserum. It was antigenically 

 different from the factor elaborated by Streptococcus hemolyticus. 

 Neter and Witebsky (1936) and Witebsky and Neter (1936) re- 

 ported that of 78 strains of pneumococcus, 31 strains produced, while 

 47 strains did not produce the fibrinolytic factor. Several strains of 

 Escherichia coli, B. lactis aero genes, B. friedlaenderi, B. fjocyaneus 

 and B. froteus were reported to produce this factor when cultured in 

 meat-infusion broth containing 2 per cent glucose. 



The observation by Neter and Witebsky (1936) that the cultures 

 of many organisms which had been grown in a medium containing 2 

 per cent glucose possess anticoagulant and fibrinolytic activities, has 

 been found by Tillett (1937) and Zinsser and Williams (1949) to be 

 due to a pH below 5.0 resulting from the breakdown of glucose. 



