Resistance to neutrophil killing. Aa is resistant to intracellular killing by neutrophils due to the production of catalase and superoxide dismutase. Some spirochetes can resist intracellular killing by preventing fusion of lysosomes with the phagosome. Aa produces an immunosuppressive factor that inhibits critical functions of lymphoid cells such as blastogenesis, antibody production and cytokine synthesis. This factor also selectively activates T-suppressor cells.
Some spirochetes can also selectively inhibit the proliferative response of lymphocytes.
Host Factors in Periodontal Diseases Immunopathology. As in many infections, the pathology associated with periodontitis may be caused by immunopathogenic mechanisms. The immune system can contribute to periodontal damage through anaphylactic reactions, immune complex mediated hypersensitivity, and delayed type hypersensitivity. Although difficult to definitively prove, there appears to be a genetic component to susceptibility to some periodontal diseases, in particular LJP and generalized prepuberal periodontitis. In many LJP patients the neutrophils lack the surface molecule GP110 that is required for an efficient chemotactic response.