ANTIBODIES AGAINST RESPIRATORY ENZYMES 



397 



not against luciferin. The antibody was destroyed at 70°C. but not at 

 61 °C. by heating for thirty minutes. Absence of luminescence was 

 used as the criterion for testing the presence of anti-luciferase in the 

 sera of rabbits immunized with a luciferase-containing extract from 

 Cyfridina hilgendorfi, an ostracod crustacean. The serum of a normal 

 rabbit recently injected with luciferase produces a bright light with 

 luciferin when tested at intervals for three to four hours. The lumi- 

 nescence gradually becomes less and disappears in ten hours. The lucif- 

 erase is destroyed in some way in the normal rabbit. The same rabbit 

 after receiving seven repeated injections of luciferase over a period of 

 twenty days was tested at intervals in the same manner, and it was 

 found that in immune serum the luciferase remained in the blood for 

 less than three hours. 



The antiluciferase content of the immune serum was tested as fol- 

 lows: The luciferase (100 mg. of material in 15 ml. of 0.8 per cent 

 sodium chloride) was mixed with varying amounts of immune serum; 

 the mixture was allowed to stand for 15 minutes and then 15 drops 

 of fresh luciferin (100 mg. of material in 0.8 per cent sodium 

 chloride) solution were added as in the following table. 



Table XXII 



The results show that the ability of luciferase to produce light with 

 luciferin can be completely prevented provided enough immune 

 serum is added. Five minutes were sufficient for complete suppression 

 of the luminescent power of one drop of luciferase mixed with eight 

 drops of immune serum. 



The rabbits immunized with luciferase solution, which also con- 

 tained oxyluciferin, showed no unequivocal evidence of having de- 

 veloped an anti-luciferin. 



