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Updated: Aug 30, 2026
Laboratory Techniques Used to Maintain and Differentiate Biotypes of Vibrio cholerae Clinical and Environmental Isolates
Published on: May 30, 2017
Macrophage distinguishes Vibrio cholerae hemolysin from its protease insensitive oligomer by time dependent and
Avijit Ray1, Kausik Chattopadhyay, Kalyan K Banerjee
1Division of Immunology and Vaccine Development, National Institute of Cholera and Enteric Diseases, P-33, CIT Road, Scheme XM, 700 010, Kolkata, India.
Abstract:
The monomeric and oligomeric forms of Vibrio cholerae hemolysin (HlyA), a membrane damaging toxin that forms transmembrane pentameric diffusion channels in target eukaryotic membrane, show a pronounced difference in protease susceptibility, presumably due to masking of sensitive peptide bonds during oligomerization. In this work, we examined if resistance of a protein to proteolytic processing affects the expression of costimulatory molecules, CD80 and CD86, on macrophage exposed to the same antigen. The murine peritoneal cavity macrophages expressed both CD80 and CD86 after 24 h of incubation with HlyA monomer but failed to express the costimulatory molecules when treated with the HlyA oligomer. The expression of CD80 molecule on macrophage after 48 h by the HlyA oligomer that failed to express the costimulatory molecules after 24 h indicates that proteolytic processing plays a decisive role in expression of CD80 and CD86 on cell surface.
Insights
Vibrio cholerae hemolysin (HlyA) oligomers resist protease digestion more than monomers. This resistance impacts macrophage costimulatory molecule expression, suggesting proteolytic processing is key for CD80 and CD86 presentation.
Area of Science:
- Immunology
- Microbiology
- Molecular Biology
Background:
- Vibrio cholerae hemolysin (HlyA) is a pore-forming toxin.
- Monomeric and oligomeric HlyA exhibit differential protease susceptibility.
- Costimulatory molecules CD80 and CD86 are crucial for macrophage activation.
Purpose of the Study:
- To investigate the effect of HlyA's proteolytic resistance on macrophage costimulatory molecule expression.
- To determine if protein processing influences antigen presentation by macrophages.
Main Methods:
- Treatment of murine peritoneal macrophages with monomeric and oligomeric HlyA.
- Analysis of CD80 and CD86 expression on macrophages via incubation assays.
- Time-course assessment of costimulatory molecule expression.
Main Results:
- Macrophages expressed CD80 and CD86 upon incubation with HlyA monomer within 24 hours.
- Macrophages failed to express CD80 and CD86 when treated with HlyA oligomer at 24 hours.
- Delayed expression of CD80 was observed with HlyA oligomer treatment after 48 hours.
Conclusions:
- Proteolytic processing of HlyA significantly influences the expression of macrophage costimulatory molecules CD80 and CD86.
- Resistance to proteolytic degradation by HlyA oligomers impairs the presentation of these immune signaling molecules.
- This suggests a critical role for protein processing in regulating immune cell activation pathways.
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