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Platelet microbicidal activity is an important defense factor against viridans streptococcal endocarditis
J Dankert1, J Krijgsveld, J van Der Werff
1Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands. M.J.Beets@amc.uva.nl
The Journal of Infectious Diseases
|August 9, 2001
Summary
Platelet microbicidal activity is crucial for fighting infective endocarditis (IE) caused by viridans streptococci (VS). Enhancing this platelet defense mechanism could improve host resistance against this serious heart infection.
Area of Science:
- Immunology
- Microbiology
- Cardiovascular Medicine
Background:
- Infective endocarditis (IE) is a serious infection of the heart lining, often caused by viridans streptococci (VS).
- Platelets play a role in host defense, but their specific contribution to combating VS-induced IE is not fully understood.
Purpose of the Study:
- To investigate the role of platelet microbicidal activity in host defense against infective endocarditis (IE) caused by viridans streptococci (VS).
- To determine if resistance to platelet microbicidal factors influences the development of IE.
Main Methods:
- Compared the susceptibility of blood and oral VS isolates from patients with and without IE to platelet releasates.
- Investigated the effect of neutralizing platelet microbicidal activity in two experimental IE models.
- Assessed the impact of vaccination with platelet components on experimental IE outcomes.
Main Results:
- VS isolates from the blood of IE patients and oral VS isolates showed increased resistance to platelet releasates compared to VS from bacteremic patients without IE.
- Vaccination with platelet components neutralized platelet microbicidal activity and increased susceptibility to experimental IE in rabbits.
- Antibodies generated recognized key platelet microbicidal proteins like thrombocidin-1 and -2.
Conclusions:
- Platelet-released microbicidal activity is a significant host defense mechanism against infective endocarditis caused by viridans streptococci.
- Resistance to platelet microbicidal factors is associated with a higher risk of developing IE.
- Targeting or enhancing platelet microbicidal function may represent a therapeutic strategy for IE.