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The effect of Pseudomonas aeruginosa on the immunogenicity of enterobacterial common antigen
Abstract:
Pseudomonas aeruginosa produces a factor (PF) which alters the enterobacterial common antigen (ECA). Its effect on the immunogenicity of two types of immunogenic ECA, namely, the ethanol-soluble preparation freed of lipopolysaccharide and the LPS-coupled form from the R-mutant E. coli 014 was investigated. The antibody response following intravenous immunization was determined by means of the hemagglutination test. It is shown that PF abolishes the immunogenicity of the former but not of the latter. PF obtained from a strain of P. maltophilia yielded the same results. Antiserum against Pseudomonas aeruginosa of types 1 and 6 neutralizes PF produced by either type. These results suggest that PF alters the lipid part and not the haptenic determinant of ECA and that this activity is neutralized by P. aeruginosa antiserum of either type 1 or type 6. This interpretation is compatible with the identification of PF as a lipase.
Insights
Pseudomonas aeruginosa produces a factor that alters the enterobacterial common antigen (ECA). This factor abolishes the immunogenicity of one ECA type but not another, suggesting it targets the lipid component.
Area of Science:
- Microbiology
- Immunology
- Biochemistry
Background:
- Enterobacterial common antigen (ECA) is a conserved antigen in Gram-negative bacteria.
- Pseudomonas aeruginosa produces a factor (PF) that modifies ECA.
- The immunogenicity of ECA can vary depending on its preparation and association with lipopolysaccharide (LPS).
Purpose of the Study:
- To investigate the effect of Pseudomonas factor (PF) on the immunogenicity of two distinct forms of enterobacterial common antigen (ECA).
- To determine if PF alters the antibody response to ECA.
- To explore the neutralizing capacity of anti-Pseudomonas aeruginosa antiserum against PF.
Main Methods:
- Preparation of two immunogenic ECA types: ethanol-soluble and LPS-coupled.
- Intravenous immunization of animals with ECA preparations.
- Assessment of antibody response using the hemagglutination test.
- Testing the effect of PF from Pseudomonas aeruginosa and Pseudomonas maltophilia.
Main Results:
- PF abolished the immunogenicity of the ethanol-soluble ECA preparation.
- PF did not abolish the immunogenicity of the LPS-coupled ECA.
- PF from P. maltophilia exhibited similar effects.
- Antiserum against P. aeruginosa types 1 and 6 neutralized PF.
Conclusions:
- PF alters the lipid portion of ECA, not the haptenic determinant.
- The activity of PF is neutralized by specific anti-Pseudomonas aeruginosa antiserum.
- PF is likely a lipase, based on its activity and neutralization by antiserum.