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Phospholipase D-neutralization in serodiagnosis of Arcanobacterium haemolyticum and Corynebacterium
B Skalka1, I Literák, P Chalupa
1Department of Microbiology, Masaryk University Medical School, Brno, Czech Republic.
Abstract:
Phospholipase D (PLD) neutralization was used to examine sera of humans (n = 40) with a spontaneous infection by Arcanobacterium haemolyticum, sheep and goats (n = 76 and 79 respectively) with a spontaneous infection by Corynebacterium pseudotuberculosis, mice (n = 26) experimentally immunized with PLD from A. haemolyticum (PLD-A) and mice (n = 28) experimentally immunized with PLD from C. pseudotuberculosis (PLD-C). PLD-A and PLD-C were also used as neutralizing antigens. A positive result of neutralization was due to an inhibition of the haemolytic synergism with the equi factor from Rhodococcus equi. The titres of sera neutralizing the homologous PLD were always significantly higher than those neutralizing the heterologous PLD. The proportion of sera that were able to neutralize the homologous PLD in sheep, goats and mice immunized with PLD-A significantly exceeded the proportion of sera that neutralized the heterologous PLD. The antigenic properties of PLD-A and PLD-C were similar but not identical.
Insights
Antibodies targeting Phospholipase D (PLD) from Arcanobacterium haemolyticum and Corynebacterium pseudotuberculosis show higher neutralization of their homologous targets. This indicates distinct antigenic properties between PLD-A and PLD-C.
Area of Science:
- Microbiology
- Immunology
- Veterinary Medicine
Background:
- Phospholipase D (PLD) is an important virulence factor in bacteria like Arcanobacterium haemolyticum and Corynebacterium pseudotuberculosis.
- Neutralizing antibodies against bacterial PLD can be crucial for developing effective vaccines and diagnostics.
Purpose of the Study:
- To investigate the antigenic similarities and differences between PLD from A. haemolyticum (PLD-A) and C. pseudotuberculosis (PLD-C).
- To assess the neutralizing antibody responses in humans, sheep, goats, and mice against homologous and heterologous PLD.
Main Methods:
- Sera from infected humans, sheep, goats, and experimentally immunized mice were tested for PLD neutralization.
- PLD-A and PLD-C were used as neutralizing antigens, with neutralization confirmed by inhibition of hemolytic synergism with the equi factor from Rhodococcus equi.
Main Results:
- Titers of sera neutralizing homologous PLD were significantly higher than those neutralizing heterologous PLD.
- In sheep, goats, and mice immunized with PLD-A, the proportion of sera neutralizing homologous PLD significantly exceeded those neutralizing heterologous PLD.
- The antigenic properties of PLD-A and PLD-C were found to be similar but not identical.
Conclusions:
- PLD from A. haemolyticum and C. pseudotuberculosis possess distinct antigenic epitopes, leading to higher homologous antibody neutralization.
- The findings suggest that while cross-protection might occur, targeting specific PLD variants could be more effective for therapeutic or prophylactic interventions.