Hematopoietic-specific targeting of influenza A virus reveals replication requirements for induction of antiviral immune responses

Abstract

A coordinated innate and adaptive immune response, orchestrated by antigen presenting cells (APCs), is required for effective clearance of influenza A virus (IAV). Although IAV primarily infects epithelial cells of the upper respiratory tract, APCs are also susceptible. To determine if virus transcription in these cells is required to generate protective innate and adaptive immune responses, we engineered IAV to be selectively attenuated in cells of hematopoietic origin. Incorporation of hematopoietic-specific miR-142 target sites into the nucleoprotein of IAV effectively silenced virus transcription in APCs, but had no significant impact in lung epithelial cells. Here we demonstrate that inhibiting IAV replication in APCs in vivo did not alter clearance, or the generation of IAV-specific CD8 T cells, suggesting that cross-presentation is sufficient for cytotoxic T lymphocyte activation. In contrast, loss of in vivo virus infection, selectively in APCs, resulted in a significant reduction of retinoic acid-inducible gene I-dependent type I IFN (IFN-I). These data implicate the formation of virus replication intermediates in APCs as the predominant trigger of IFN-I in vivo. Taking these data together, this research describes a unique platform to study the host response to IAV and provides insights into the mechanism of antigen presentation and the induction of IFN-I.

Swift and Strong NK Cell Responses Protect 129 Mice against High-Dose Influenza Virus Infection

“…A variety of host cells, including ciliated epithelial cells, type I and II alveolar cells, and immune cells, are infected by IAV within the respiratory tract (1)(2)(3)(4). IAV-infected cells are eliminated through two major mechanisms: viral replication-mediated apoptosis or necrosis (5,6) and immune system-mediated viral clearance (7,8).…”

Insights into RNA Interference as Antiviral Defense

“…The group of human miRNAs including miR-28, miR-125b, miR-150, miR-223 and miR-382 targets 3' end of HIV-1 mRNAs and significantly decrease HIV-1 replication in n resting CD4 + T cells [40]. Similarly, mir-let-7c, mir-192 and mir-142 inhibit influenza virus replication [41][42][43].…”

Plasmacytoid Dendritic Cells Require Direct Infection To Sustain the Pulmonary Influenza A Virus-Specific CD8 T Cell Response

“…Recently, Langlois et al described an IAV containing four perfect targeting sequences for a hematopoietic cell-specific microRNA (miR-142) at the 3= end of the nucleocapsid protein (NP) mRNA of A/PR/8/34 (142t-IAV) (14). As miR-142 is exclusively expressed in cells of hematopoietic origin (15), the NP mRNA is targeted for degradation, efficiently restricting replication of this virus within hematopoietic cells (14).…”

“…As miR-142 is exclusively expressed in cells of hematopoietic origin (15), the NP mRNA is targeted for degradation, efficiently restricting replication of this virus within hematopoietic cells (14). While early RIG-I-mediated type I IFN production was reduced following infection with 142t-IAV, similar viral titers and clearance rates, weight loss, and accumulation of IAV-specific CD8 T cells were observed following infection with 142t-IAV compared to a control A/PR/8/34 (ctrl-IAV) containing random nucleotides instead of the miR142 targeting sequence (14). Further, even though the frequency of CD45 ϩ CD11c ϩ that are hemagglutinin positive (HA ϩ ; i.e., infected) is significantly reduced in 142t-IAV infected mice compared to ctrl-IAV-infected mice, this virus does not appear to be attenuated.…”