Related Experiment Videos
Monoclonal antibody-mediated protection and neutralization of motility in experimental Proteus mirabilis infection
R C Harmon1, R L Rutherford, H M Wu
1Research and Development, Cutter-Biological, Berkeley, California.
Abstract:
A panel of monoclonal antibodies with specificity for a wound isolate of Proteus mirabilis was established. Of nine antibodies studied in detail, three were broadly reactive with various Proteus isolates, while six reacted in a serotype-specific fashion with the strain used for immunization. Five of the six serotype-specific antibodies were reactive with lipopolysaccharide. The sixth serotype-specific antibody, 4-F (immunoglobulin G1 [IgG1]), was potently protective in a burn wound sepsis model and recognized a protein antigen. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot (immunoblot) analysis were used to determine that 4-F was reactive with flagellar protein. Approximately 1.3 micrograms of the antibody was sufficient to provide protection against 8 50% lethal doses of wound isolate, and approximately 26 micrograms provided full protection against challenge with 333 50% lethal doses. In vitro test results indicated that 4-F inhibited the motility of the wound isolate, and in vivo testing showed that it inhibited dissemination of the inoculum from the burn site to the liver and spleen. Whereas the antibody was highly effective in preventing the death of mice subsequent to challenge at a burn site, no protection was seen following an intraperitoneal challenge. These results may therefore indicate that the protection observed in the burn model is solely a reflection of the capacity of 4-F to neutralize bacterial motility.
Insights
A novel monoclonal antibody, 4-F (immunoglobulin G1), effectively protected against Proteus mirabilis wound infections by neutralizing bacterial motility. This antibody targets flagellar protein, showing potent protection in a burn wound sepsis model.
Area of Science:
- Immunology
- Microbiology
- Infectious Diseases
Background:
- Proteus mirabilis is a significant opportunistic pathogen, particularly in wound infections.
- Developing targeted therapies against specific bacterial virulence factors is crucial for combating infections.
Purpose of the Study:
- To establish and characterize monoclonal antibodies against a wound isolate of Proteus mirabilis.
- To evaluate the protective efficacy of a specific antibody (4-F) in a burn wound sepsis model.
Main Methods:
- Generation and screening of monoclonal antibodies against Proteus mirabilis.
- Serotyping and antigen characterization (lipopolysaccharide, flagellar protein) using Western blot.
- Assessment of antibody efficacy in a murine burn wound sepsis model (in vivo) and bacterial motility assays (in vitro).
Main Results:
- Six of nine monoclonal antibodies were serotype-specific, with five targeting lipopolysaccharide.
- The antibody 4-F (IgG1) recognized flagellar protein and demonstrated potent protection in a burn wound model.
- 4-F inhibited bacterial motility in vitro and prevented dissemination from the burn site in vivo, but not after intraperitoneal challenge.
Conclusions:
- Monoclonal antibody 4-F confers protection against Proteus mirabilis burn wound sepsis primarily by neutralizing bacterial motility.
- Targeting flagellar protein with specific antibodies represents a potential therapeutic strategy for P. mirabilis infections.