Chitosan alters inactivated respiratory syncytial virus vaccine elicited immune responses without affecting lung histopathology in mice.

Abstract

Chitosan is a polysaccharide capable of augmenting immune responses with a proven safety record in animals and humans. These properties make it a potentially attractive agent for the prevention and treatment of infectious disease. Infection by respiratory syncytial virus (RSV) is the leading cause of serious lower respiratory disease in young children throughout the world. There is no licensed vaccine available against RSV whereas inactivated vaccine is known to cause enhanced respiratory disease instead of protection. Here, we investigated whether chitosan administered one or three days post-infection could protect animals against RSV infection and whether it could alter immune responses or immunopathology induced by inactivated RSV vaccine when administered twice before RSV infection. We found chitosan could modestly protect animals against RSV infection when given post-infection, while, in conjunction with inactivated RSV vaccine when given pre-infection, it could significantly reduce RSV infection in mice. Further mechanistic investigation revealed that chitosan enhanced antigen-specific immune responses through augmenting the induction of regulatory T cells, lung resident T cells and neutralizing antibodies while reversing Th2-skewed immune responses induced by inactivated RSV vaccine but, surprisingly, failing to reverse lung histopathology. Overall, this study sheds more light on the molecular mechanisms underlying inactivated RSV vaccine-induced disease.

• Authors: Abenaya Muralidharan, Marsha S Russell, Louise Larocque, Caroline Gravel, Simon Sauvé, Ze Chen, Changgui Li, Wangxue Chen, Terry Cyr, Michael Rosu-Myles, Lisheng Wang, Xuguang Li
• Journal: Vaccine (Vaccine) Vol. 37 Issue 30 Pg. 4031-4039 (07 09 2019) ISSN: 1873-2518 [Electronic] Netherlands
• PMID: 31186190 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Crown Copyright © 2019. Published by Elsevier Ltd. All rights reserved.

Chemical References

• Antibodies, Neutralizing
• Respiratory Syncytial Virus Vaccines
• Chitosan

Topics

• Animals
• Antibodies, Neutralizing (metabolism)
• Chitosan (therapeutic use)
• Enzyme-Linked Immunosorbent Assay
• Female
• Flow Cytometry
• Lung (pathology, virology)
• Mice
• Mice, Inbred BALB C
• Respiratory Syncytial Virus Infections (immunology, prevention & control)
• Respiratory Syncytial Virus Vaccines (therapeutic use)
• Respiratory Syncytial Virus, Human (drug effects, immunology, pathogenicity)
• T-Lymphocytes (metabolism)
• T-Lymphocytes, Regulatory (metabolism)