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Biphasic protection against bacterial infection in mice induced by vaccination of Propionibacterium acnes
Abstract:
A single intraperitoneal injection of the phenol-treated cells of Propionibacterium acnes into mice showed nonspecific resistance against subsequent lethal doses of an intraperitoneal challenge of Klebsiella pneumoniae, Staphylococcus aureus, and Streptococcus pyogenes. The protection showed a biphasic pattern. The maximum protection, designated as the early phase protection, was seen in mice injected with P. acnes vaccine 1 to 2 days before the challenge, whereas the late phase protection was seen in mice vaccinated 16 to 22 days before the challenge. The activity of the reticuloendothelial system in mice after vaccination also showed a biphasic pattern with the peak on days 4 and 12. The delayed activation of the reticuloendothelial system lasted up to 3 weeks and coincided with the period of the late phase protection. The early phase resistance was markedly impaired by the treatment with hydrocortisone and carrageenan, but not by the treatment with anti-thymocyte serum, actinomycin D, or cyclophosphamide. The number of peritoneal polymorphonuclear leukocytes in vaccinated mice increased on days 1 to 2. The number of macrophages also increased at 2 to 21 days after vaccination and reached its maximum on day 14. Total activities of acid phosphatase, Nitro Blue Tetrazolium reduction, and the phagocytic activities of peritoneal exudate cells were also enhanced on and after day 1 after the injection of P. acnes vaccine.
Insights
Propionibacterium acnes (P. acnes) vaccination induces biphasic, nonspecific resistance against bacterial infections in mice. This immune enhancement involves early and late phases, with distinct reticuloendothelial system activity patterns.
Area of Science:
- Immunology
- Microbiology
- Infectious Diseases
Background:
- Propionibacterium acnes (P. acnes) is a bacterium known to modulate the immune system.
- Understanding non-specific resistance mechanisms is crucial for developing broad-spectrum antimicrobial strategies.
Purpose of the Study:
- To investigate the non-specific immune resistance induced by P. acnes vaccination in a murine model.
- To characterize the temporal pattern and underlying mechanisms of P. acnes-mediated protection against bacterial challenge.
Main Methods:
- Mice were intraperitoneally injected with phenol-treated P. acnes cells.
- Subsequent challenge with lethal doses of Klebsiella pneumoniae, Staphylococcus aureus, and Streptococcus pyogenes.
- Assessment of immune cell activity, reticuloendothelial system function, and the impact of immunosuppressive agents.
Main Results:
- P. acnes vaccination conferred biphasic protection against lethal bacterial challenge.
- Early phase protection (1-2 days post-vaccination) was sensitive to hydrocortisone and carrageenan.
- Late phase protection (16-22 days post-vaccination) correlated with enhanced reticuloendothelial system activity and increased macrophage populations.
Conclusions:
- P. acnes vaccination induces a complex, biphasic immune response conferring non-specific resistance.
- The early and late phases of protection involve distinct immunological mechanisms.
- This study highlights P. acnes as a potential agent for modulating host defense against diverse bacterial pathogens.