CHEMICAL AND IMMUNOLOGICAL COMPOSITION OF SURFACE STRUCTURES OF LISTERIA MONOCYTOGENES.

Osebold, John W. (University of California, Davis), Ole Aalund, and Clarence E. Chrisp. Chemical and immunological composition of surface structures of Listeria monocytogenes. J. Bacteriol. 89:84-88. 1965.-A proteinlike surface substance was demonstrated on Listeria monocytogenes when an explanation was sought for the inagglutinability of some somatic antigens. The serological behavior of live bacteria and organisms subjected to heat, formalin, and trypsin was compared. The agglutination-inhibiting phenomenon was most pronounced with heat-killed (100 C) antigens. Trypsinization eliminated inagglutinability and increased sensitivity. Substances released by the enzyme had an ultraviolet-absorption peak at 260 mmu and showed a spot on paper chromatograms compatible with polypeptide. Inagglutinable cells combined with antibody because they could readily absorb antibodies from serum. After reaction with anti-Listeria serum, inagglutinable cells could be agglutinated by the addition of antiglobulin serum. It was hypothesized that heat inactivation of cells denatured the proteinaceous surface layer which interferred with the formation of a visible agglutination product but did not eliminate antigen-antibody reaction.