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An In vitro Model to Study Immune Responses of Human Peripheral Blood Mononuclear Cells to Human Respiratory Syncytial Virus Infection
Published on: December 10, 2013
Functional Impairment of Mononuclear Phagocyte System by the Human Respiratory Syncytial Virus
Karen Bohmwald1, Janyra A Espinoza1, Raúl A Pulgar1
1Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.
Abstract:
The mononuclear phagocyte system (MPS) comprises of monocytes, macrophages (MΦ), and dendritic cells (DCs). MPS is part of the first line of immune defense against a wide range of pathogens, including viruses, such as the human respiratory syncytial virus (hRSV). The hRSV is an enveloped virus that belongs to the Pneumoviridae family, Orthopneumovirus genus. This virus is the main etiological agent causing severe acute lower respiratory tract infection, especially in infants, children and the elderly. Human RSV can cause bronchiolitis and pneumonia and it has also been implicated in the development of recurrent wheezing and asthma. Monocytes, MΦ, and DCs significantly contribute to acute inflammation during hRSV-induced bronchiolitis and asthma exacerbation. Furthermore, these cells seem to be an important component for the association between hRSV and reactive airway disease. After hRSV infection, the first cells encountered by the virus are respiratory epithelial cells, alveolar macrophages (AMs), DCs, and monocytes in the airways. Because AMs constitute the predominant cell population at the alveolar space in healthy subjects, these cells work as major innate sentinels for the recognition of pathogens. Although adaptive immunity is crucial for viral clearance, AMs are required for the early immune response against hRSV, promoting viral clearance and controlling immunopathology. Furthermore, exposure to hRSV may affect the phagocytic and microbicidal capacity of monocytes and MΦs against other infectious agents. Finally, different studies have addressed the roles of different DC subsets during infection by hRSV. In this review article, we discuss the role of the lung MPS during hRSV infection and their involvement in the development of bronchiolitis.
Insights
The mononuclear phagocyte system (MPS), including monocytes, macrophages, and dendritic cells, plays a critical role in the early immune response to human respiratory syncytial virus (hRSV). These cells are vital for viral clearance and controlling inflammation in hRSV-induced bronchiolitis.
Area of Science:
- Immunology
- Virology
- Respiratory Medicine
Background:
- The mononuclear phagocyte system (MPS), comprising monocytes, macrophages (MΦ), and dendritic cells (DCs), is crucial for innate immunity against pathogens like human respiratory syncytial virus (hRSV).
- hRSV is a major cause of severe lower respiratory tract infections, particularly in infants and the elderly, leading to bronchiolitis, pneumonia, and potentially asthma.
- MPS cells in the airways are among the first responders to hRSV infection, influencing both viral clearance and immunopathology.
Purpose of the Study:
- To review and discuss the multifaceted roles of the lung mononuclear phagocyte system during hRSV infection.
- To elucidate the involvement of MPS components in the pathogenesis of hRSV-induced bronchiolitis and reactive airway diseases.
- To highlight the importance of alveolar macrophages (AMs) as key sentinels in the early innate immune response to hRSV.
Main Methods:
- This is a review article, synthesizing findings from existing scientific literature.
- Analysis of studies focusing on the cellular and molecular interactions between hRSV and MPS components.
- Examination of the contribution of monocytes, macrophages, and dendritic cells to inflammation and immune responses during hRSV infection.
Main Results:
- Alveolar macrophages are essential for early hRSV recognition, viral clearance, and control of immunopathology, despite the importance of adaptive immunity.
- Monocytes, MΦs, and DCs significantly contribute to acute inflammation associated with hRSV-induced bronchiolitis and asthma exacerbation.
- hRSV infection can impair the phagocytic and microbicidal functions of monocytes and MΦs against other pathogens, and different DC subsets play distinct roles.
Conclusions:
- The lung mononuclear phagocyte system is central to the host's defense against hRSV, influencing disease severity and outcomes.
- Understanding the dynamics of MPS cells in hRSV infection is critical for developing effective therapeutic strategies against respiratory infections and related airway diseases.
- Further research into the specific functions of different MPS subsets, particularly DCs, in hRSV infection is warranted.
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