Flu Virus Attenuates Memory Clearance of Pneumococcus via IFN-?-Dependent Th17 and Independent Antibody Mechanisms.

ABSTRACT: Bacterial coinfection is a major cause of influenza-associated mortality. Most people have experienced infections with bacterial pathogens commonly associated with influenza A virus (IAV) coinfection before IAV exposure; however, bacterial clearance through the immunological memory response (IMR) in coinfected patients is inefficient, suggesting that the IMR to bacteria is impaired during IAV infection. Adoptive transfer of CD4⁺ T cells from mice that had experienced bacterial infection into IAV-infected mice revealed that memory protection against bacteria was weakened in the latter. Additionally, memory Th17 cell responses were impaired due to an IFN-?-dependent reduction in Th17 cell proliferation and delayed migration of CD4⁺ T cells into the lungs. A bacterium-specific antibody-mediated memory response was also substantially reduced in coinfected mice, independently of IFN-?. These findings provide additional perspectives on the pathogenesis of coinfection and suggest additional strategies for the treatment of defective antibacterial immunity and the design of bacterial vaccines against coinfection.

SUBMITTER: Li N 

PROVIDER: S-EPMC7683269 | biostudies-literature | 2020 Dec

REPOSITORIES: biostudies-literature