Difficulties in producing antibodies to purified Propionibacterium acnes exocellular enzymes

Attempts were made to produce antisera to purified preparations of Propionibacterium acnes lipase, hyaluronate lyase and acid phosphatase in rabbits. Antiserum to lipase (neutralizing titre I:32) was produced using conventional methods. Lipase (30 micrograms) in Freund's complete adjuvant (FCA) was injected into multiple sites thrice at weekly intervals. Antibody levels were boosted by i.v. injections of 30 micrograms in saline at 2-weekly intervals for 2 months. Such regimes failed to raise antibodies to hyaluronate lyase and acid phosphatase. In order to produce antiserum to hyaluronate lyase, rabbit mononuclear cells were incubated with 45 micrograms of hyaluronate lyase in vitro (I h at 37 degrees C) prior to injection subcutaneously above the rabbit ankle joint. Simultaneous injections of hyaluronate lyase in FCA (45 micrograms) were administered into the footpad and thigh. Three treatments at weekly intervals produced an antiserum with a neutralizing titre of I:256. A similar regime failed to raise antibodies to acid phosphatase. Antibodies to P. acnes lipase and hyaluronate lyase also neutralize the enzymes produced by P. granulosum. The neutralization curves suggest that the enzymes produced by both species are related antigenically but not identical.