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Natural and immune cytolysis of canine distemper virus-infected target cells
Abstract:
Natural and immune cytolysis of canine distemper virus (CDV)-infected target cells in vitro is described. Lymphocytes expressing natural cytotoxicity were found in specific-pathogen-free beagle dogs and in beagle-coonhound crosses before vaccination with CDV and indefinitely after vaccination, when the ephemeral immune lymphocyte-mediated cytotoxicity (ILMC) had declined. In contrast to the natural lymphocyte-mediated cytotoxicity, the ILMC was genetically restricted, could not be blocked by CDV-specific antibody, and was effective against measles virus-infected as well as CDV-infectd target cells. Lymphocyte populations were depleted of Fc receptor and surface immunoglobulin-bearing cells by rosetting techniques and tested in comparison. An antibody-dependent cell-mediated cytotoxicity was demostrated against CDV-infected target cells that were preincubated with CDV antibody when Fc receptor-bearing lymphocytes were not removed. The ILMC was measurable for approximately 10 days beginning at 6 days post-vaccination. In contrast, CDV antibody measured by virus neutralization and humoral cytotoxicity was detectable by 6 days postvaccination and persisted at peak levels for at least 5 months.
Insights
Natural and immune cell responses to canine distemper virus (CDV) were studied. Natural cytotoxicity persists post-vaccination, unlike transient immune lymphocyte-mediated cytotoxicity (ILMC).
Area of Science:
- Immunology
- Virology
- Cellular Cytotoxicity
Background:
- Canine distemper virus (CDV) infection poses a significant threat to canine health.
- Understanding the immune response to CDV is crucial for vaccine development and efficacy.
- In vitro studies are essential for dissecting specific immune mechanisms against viral infections.
Purpose of the Study:
- To describe and compare natural and immune-mediated cytolysis of CDV-infected cells.
- To characterize the kinetics and specificity of immune lymphocyte-mediated cytotoxicity (ILMC) post-vaccination.
- To investigate the role of Fc receptor-bearing lymphocytes in antibody-dependent cell-mediated cytotoxicity (ADCC).
Main Methods:
- In vitro assessment of natural and immune cytolysis using CDV-infected target cells.
- Depletion of lymphocyte populations (Fc receptor and surface immunoglobulin-bearing cells) via rosetting techniques.
- Measurement of CDV antibody levels using virus neutralization and humoral cytotoxicity assays.
Main Results:
- Natural lymphocyte-mediated cytotoxicity was present before and persisted long after CDV vaccination.
- Immune lymphocyte-mediated cytotoxicity (ILMC) was transient, genetically restricted, and effective against both CDV and measles virus.
- Antibody-dependent cell-mediated cytotoxicity (ADCC) was demonstrated against CDV-infected cells.
- CDV-specific antibodies were detectable early post-vaccination and persisted for at least 5 months, unlike the short-lived ILMC.
Conclusions:
- Distinct lymphocyte populations mediate natural and immune responses to CDV infection.
- ILMC plays a temporary role in viral clearance, while humoral immunity provides long-lasting protection.
- Fc receptor-bearing cells are critical for ADCC in the context of CDV infection.