Related Experiment Videos
Salmonella. typhi OMPs induced immunomodulation in peritoneal macrophages
D R Kashyap1, S Sood, R P Tiwari
1Department of Microbiology, Panjab University, Chandigarh-160014, India.
Abstract:
The immunomodulatory properties of outer membrane proteins (OMPs) from S. typhi Ty2 were studied in mouse model at 72 hr and 20 days post-infection. Inspite of reduction in the number of macrophages and their protein content observed in the immunized group vis-à-vis infected group, OMPs activated macrophages showed significant upregulation of NO. At 20 days post infection, the level remained almost the same suggesting the prolonged cytotoxic and cytostatic activity due to the long lasting effects of OMPs activated macrophages. Higher activity of SOD in these aged cells pointed out towards the protective efficacy of OMPs to keep the macrophages themselves away from the noxious effects of O2-. Lower level of acid phosphatase in the macrophages from immunized mice group indicated the involvement of oxygen dependent rather than oxygen independent killing process. The enhanced uptake of organisms and their killing could be related to the production of oxygen and nitrogen radicals in the OMPs immunized group.
Insights
Outer membrane proteins (OMPs) from S. typhi Ty2 activate macrophages, enhancing their ability to kill bacteria. These activated macrophages exhibit prolonged cytotoxic effects and are protected from oxidative damage.
Area of Science:
- Immunology
- Microbiology
- Cellular Biology
Background:
- Salmonella typhi outer membrane proteins (OMPs) are key virulence factors.
- Understanding OMP immunomodulatory effects is crucial for developing effective vaccines and therapies.
Purpose of the Study:
- To investigate the immunomodulatory properties of S. typhi Ty2 OMPs in a mouse model.
- To assess the impact of OMPs on macrophage activation, bacterial killing, and oxidative stress.
Main Methods:
- Mice were immunized with S. typhi Ty2 OMPs and infected.
- Macrophage counts, protein content, nitric oxide (NO) production, superoxide dismutase (SOD) activity, and acid phosphatase levels were measured at 72 hours and 20 days post-infection.
Main Results:
- OMP-activated macrophages showed increased NO production, indicating enhanced cytotoxic and cytostatic activity.
- Higher SOD activity in OMP-treated macrophages suggested protection against oxidative stress.
- Lower acid phosphatase levels indicated a shift towards oxygen-dependent bacterial killing mechanisms.
Conclusions:
- S. typhi Ty2 OMPs effectively activate macrophages, leading to enhanced bacterial uptake and killing.
- OMP-induced macrophage activation involves both oxygen-dependent and independent pathways, with prolonged protective effects.