Antibody titers to Propionibacterium acnes cell wall carbohydrate in nodulocystic acne patients.

In order to determine which structures in Propionibacterium acnes are most antigenic to severe acne patients, we studied the specificity of anti-P. acnes antibodies in serum from 15 nodulocystic acne patients and 5 normals. Complement fixation titers to P. acnes cell wall fractions were determined using guinea pig serum as a complement source. The mean titers of patients and normals to whole cells were 39.6 and 3 (p less than 0.1); to crude cell wall, 138 and 8 (p less than 0.01); and to protein and nucleic acid-free cell wall, 225 and 9.33 (p less than 0.001), respectively. The mean precipitin titer to P. acnes cytosol was 12.7 for patients and 0 for normals. Immunoelectrophoresis of cytosol from 8 P. acnes strains were developed with each of the 15 patient sera. A single broadly migrating anionic antigen was detected. The antigen was also present in P. acnes culture supernatants. Sephadex G-100 chromatography of cytosol revealed a single peak of antigenic reactivity at Mr = 100,000. Three patients' sera revealed a second weakly reacting antigen in the cytosol preparation. Twentyfold concentration of immunoglobulin from patient sera failed to reveal any other antigenic reactivities. The antigen was found to be resistant to nuclease, pronase, and lysozyme treatment; was precipitable with 70% ethanol; and was destroyed by sodium m-periodate--findings that are consistent with a carbohydrate structure.