Ally, adversary, or arbitrator? The context-dependent role of eosinophils in vaccination for respiratory viruses and subsequent breakthrough infections

J Leukoc Biol. 2024 Jan 30:qiae010. doi: 10.1093/jleuko/qiae010. Online ahead of print.ABSTRACTEosinophils are a critical type of immune cell and central players in Type 2 immunity. Existing literature suggests that eosinophils also can play a role in host antiviral responses, typically Type 1 immune events, against multiple respiratory viruses, both directly through release of antiviral mediators and indirectly through activation of other effector cell types. One way to prime host immune responses towards effective antiviral responses is through vaccination, where typically a Type 1-skewed immunity is desirable in the context of intracellular pathogens like respiratory viruses. In the realm of breakthrough respiratory viral infection in vaccinated hosts, an event in which virus can still establish productive infection despite pre-existing immunity, eosinophils are most prominently known for their link to vaccine-associated enhanced respiratory disease (VAERD) upon natural respiratory syncytial virus (RSV) infection. This was observed in a pediatric cohort during the 1960s following vaccination with formalin-inactivated RSV (FI-RSV). More recent research has unveiled additional roles of the eosinophil in respiratory viral infection and breakthrough infection. The specific contribution of eosinophils to the quality of vaccine responses, vaccine efficacy, and antiviral responses to infection in vaccinated hosts remains largely unexplored, especially regarding their potential ro...
Source: Journal of Leukocyte Biology - Category: Hematology Authors: Source Type: research