ANTIBODIES AGAINST RESPIRATORY ENZYMES 391 



offer two possible explanations to account for the increased phos- 

 phatase level following the infection: (a) the damage inflicted on 

 various organs by the toxic eff^ects of the infection throwing the tissue- 

 bound phosphatases into the blood stream; and (b) the autolysis of the 

 infectious agent liberating bacterial phosphatases and thereby causing 

 an increase in the serum phosphatase level of the infected host. In 

 view of the fact that in non-infectious diseases involving damage to 

 normal tissues and organs there is an increase in serum phosphatase 

 level, it may seem possible that the first alternative explanation is a 

 more plausible one. However, the amount of enzyme derived from the 

 autolysis of an infective agent could be sufficient to affect the 

 phosphatase level of the serum. Phosphatase elaborated in amounts 

 comparable to those of toxins elaborated during an infection could be 

 expected to affect the phosphatase levels of serum. 



If we accept the first explanation, it is necessary to assume that 

 the decrease of serum phosphatase level with the increasing titer of 

 agglutinin is due to the inhibition by agglutinins of the toxic or enzyme 

 processes of the infectious agent which are responsible for the specific 

 damage to the tissues causing the liberation of bound phosphatases. 

 If, on the other hand, we accept the second alternative explanation, we 

 must consider the decrease in phosphatase level with the increase of 

 agglutinin titer as due to the specific combination of the bacterial 

 phosphatase with the specific antibody present in the agglutinating 

 serum and thereby its elimination from the infected system. One. 

 may also point out the possibility that the antibody to bacterial 

 phosphatase present in the agglutinating serum could inhibit or 

 reduce the synthesis of phosphatase by the agglutinated bacteria. In 

 this connection, it is interesting to note that the animals treated with 

 living Br. abortus are afforded protection against abortion. Dead ba- 

 cilli are found to be valueless in this respect (Topley and Wilson, 

 1936). Huddleson (1943) has reported that a crushed cell fraction 

 produced active immunity in guinea pigs. This property of the active 

 fraction was susceptible to heat and antiseptics. In this respect living 

 bacteria and their fractions obtained from them behaved like enzymes. 

 Any one of the above explanations would seem to require that the 

 enzymatic activities of the immunizing agents remain intact when used 

 for active immunization. Only under these conditions would highly 

 effective homologous antibodies seem to form. 



