Related Experiment Videos
Absence of monocyte procoagulant activity during the immune response to influenza virus
Abstract:
The ability of mononuclear phagocytes (MPh) to manifest procoagulant activity (PCA) resulting in the formation of fibrin is thought to be a key MPh effector function in tissue repair. The present study addresses the question of whether monocyte PCA is confined to tissue hypersensitivity reactions or is a general correlate of all immune responses. We show here that PCA is not the obligate outcome when the immune system is stimulated. In particular, under in vitro conditions in which a mitogen (phytohemagglutinin) or an antigen (purified protein derivative of tuberculin) elicits good PCA responses, incubation with influenza virus does not result in the generation of PCA, although other parameters of response to the virus appear to be intact. Moreover, influenza virus can cause suppression of PCA when cultures are stimulated with either phytohemagglutinin, purified protein derivative of tuberculin, or endotoxin, conditions which would otherwise result in good PCA responses. This lack of PCA persists throughout the culture period and is not caused by an effect of influenza virus on the viability of either MPh or leukocytes in general.
Insights
Mononuclear phagocytes (MPh) do not always produce procoagulant activity (PCA) during immune responses. Influenza virus can inhibit MPh PCA, even when other immune functions remain intact.
Area of Science:
- Immunology
- Cell Biology
- Hematology
Background:
- Mononuclear phagocytes (MPh) exhibit procoagulant activity (PCA), forming fibrin, which is crucial for tissue repair.
- The role of MPh PCA in various immune responses beyond hypersensitivity reactions is not fully understood.
Purpose of the Study:
- To investigate whether MPh PCA is a universal outcome of immune system stimulation.
- To determine if influenza virus influences MPh PCA during immune responses.
Main Methods:
- In vitro incubation of leukocytes with mitogens (phytohemagglutinin), antigens (purified protein derivative of tuberculin), endotoxin, or influenza virus.
- Assessment of procoagulant activity (PCA) generation.
- Evaluation of leukocyte viability.
Main Results:
- Stimulation with mitogens or antigens elicited PCA, but influenza virus did not.
- Influenza virus suppressed PCA generation in cultures stimulated by other agents.
- The observed lack of PCA was not due to reduced MPh or leukocyte viability.
Conclusions:
- Procoagulant activity (PCA) is not an obligatory response of mononuclear phagocytes (MPh) to all immune stimuli.
- Influenza virus can actively suppress MPh PCA, indicating a specific immunomodulatory effect.
- These findings suggest a complex regulation of MPh procoagulant function during viral infections.