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Acquired chemotactic inhibitors during infection with guinea pig cytomegalovirus
Abstract:
Factors involved in neutrophil and monocyte migrations were serially studied in strain 2 guinea pigs undergoing initial cytomegalovirus infection and sham-inoculated controls. All studies remained unchanged in uninfected animals. Monocyte migrations and neutrophil spontaneous migration remained unchanged in infected animals. However, transient abnormalities occurred early in infection, comprising a decrease in neutrophil-directed migration towards C5-derived chemotactic fractions (C5-fr) and a decrease in the chemotactic activity of zymosan-activated plasma. Consequently, the presence of neutrophil- and chemotaxin-directed inhibitors in plasma was investigated. Normal neutrophils, C5-fr, Escherichia coli-derived bacterial factor, and the synthetic peptide F-met-leu-phe were first incubated with control or infected plasmas and then assayed for directed migration and lysosomal enzyme release. Results indicated the de novo appearance of both neutrophil- and chemotaxin-directed inhibitory activities in plasma during early infection. The neutrophil-directed inhibition was heat stable (56 degrees C for 120 min) and nonspecific (responses to all chemotaxins were inhibited). The chemotaxin-directed inhibition was heat stable and C5-fr specific. The cytomegalovirus-induced inhibitors may be important in the enhanced susceptibility to concurrent opportunistic infections.
Insights
Cytomegalovirus infection in guinea pigs causes temporary plasma inhibitors that impair neutrophil migration. These inhibitors may increase susceptibility to secondary infections.
Area of Science:
- Immunology
- Virology
- Cell Biology
Background:
- Neutrophil and monocyte migration are crucial for immune response.
- Cytomegalovirus (CMV) infection can impact host immune function.
Purpose of the Study:
- To investigate the effects of initial cytomegalovirus infection on neutrophil and monocyte migration in guinea pigs.
- To identify potential inhibitory factors in plasma during CMV infection.
Main Methods:
- Serial studies of neutrophil and monocyte migration in CMV-infected and control guinea pigs.
- Assays for chemotactic activity using C5-derived chemotactic fractions and zymosan-activated plasma.
- Incubation of neutrophils with plasma from infected/control animals to test for inhibitory activities.
Main Results:
- Monocyte migration and spontaneous neutrophil migration remained unchanged.
- Transient decrease in neutrophil-directed migration and plasma chemotactic activity early in infection.
- De novo appearance of heat-stable, non-specific neutrophil inhibitors and C5-specific chemotaxin inhibitors in plasma.
Conclusions:
- Initial CMV infection induces transient plasma inhibitors affecting neutrophil function.
- These CMV-induced inhibitors may contribute to increased susceptibility to opportunistic infections.