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Immunogenicity of Corynebacterium pseudotuberculosis and the effect of adjuvants in mice
Abstract:
Intraperitoneal inoculation of CF1 mice with 100 micrograms, 200 micrograms, or 300 micrograms whole cell (WC) or 250 micrograms, 500 micrograms, or 1000 micrograms cell wall (CW) of Corynebacterium pseudotuberculosis induced varying degrees of protection after intravenous challenge of immunity with 7.2 X 10(4) CFU of C. pseudotuberculosis. Generally, the degree of protection increased with the dose of WC or CW. However, intraperitoneal inoculation of mice with 100 micrograms, 200 micrograms, or 300 micrograms heat-killed Mycobacterium bovis BCG; 50 micrograms, 150 micrograms, or 300 micrograms of either muramyl dipeptide (MDP) or trehalose dimycolate (TDM); or 350 micrograms, 700 micrograms or 1400 micrograms Corynebacterium parvum did not induce resistance to intravenous inoculation of 7.4 X 10(4) CFU of C. pseudotuberculosis. The protection induced by 500 micrograms CW was enhanced by adding 100 micrograms BCG, 150 micrograms MDP, or 350 micrograms C. parvum but protection induced in mice by 300 micrograms of WC was not enhanced by adding any adjuvants.
Insights
Corynebacterium pseudotuberculosis whole cell (WC) and cell wall (CW) vaccines protected mice against infection, with higher doses offering more protection. Other tested adjuvants like BCG, MDP, TDM, and C. parvum did not provide protection alone but enhanced CW vaccine efficacy.
Area of Science:
- Immunology
- Microbiology
- Vaccine Development
Background:
- Corynebacterium pseudotuberculosis is an opportunistic pathogen causing significant economic losses in livestock.
- Developing effective vaccines against C. pseudotuberculosis is crucial for animal health.
- Understanding the immunomodulatory properties of bacterial components is key to vaccine design.
Purpose of the Study:
- To evaluate the protective efficacy of whole cell (WC) and cell wall (CW) vaccines derived from Corynebacterium pseudotuberculosis against homologous challenge.
- To investigate the potential of various adjuvants, including Mycobacterium bovis BCG, muramyl dipeptide (MDP), trehalose dimycolate (TDM), and Corynebacterium parvum, in enhancing vaccine-induced protection.
- To determine the dose-dependent effects of WC and CW vaccines on protection levels.
Main Methods:
- CF1 mice were intraperitoneally inoculated with varying doses of C. pseudotuberculosis WC or CW.
- Mice were subsequently challenged intravenously with a lethal dose of C. pseudotuberculosis.
- The efficacy of different adjuvants (BCG, MDP, TDM, C. parvum) was assessed by co-administration with WC or CW vaccines.
- Protection was evaluated based on survival rates and reduction in bacterial load post-challenge.
Main Results:
- Intraperitoneal administration of C. pseudotuberculosis WC and CW induced dose-dependent protection against intravenous challenge.
- Higher doses of WC and CW generally resulted in increased levels of protection.
- Heat-killed BCG, MDP, TDM, and C. parvum alone did not confer resistance to C. pseudotuberculosis infection.
- The protective effect of 500 micrograms of CW vaccine was significantly enhanced by co-administration with BCG, MDP, or C. parvum.
- However, the protection induced by 300 micrograms of WC vaccine was not improved by the addition of any tested adjuvants.
Conclusions:
- Corynebacterium pseudotuberculosis WC and CW fractions possess intrinsic protective antigen(s) against homologous challenge.
- The efficacy of CW-based vaccines can be potentiated by specific adjuvants like BCG, MDP, and C. parvum.
- WC vaccines may not benefit from the addition of these particular adjuvants, suggesting different immunogenic properties or optimal adjuvant combinations are required.
- Further research into the specific components and mechanisms of WC and CW vaccines is warranted for optimized vaccine development against C. pseudotuberculosis infections.