The gut-lung axis in influenza A: the role of gut microbiota in immune balance

Abstract

Influenza A, the most common subtype, induces 3 to 5 million severe infections and 250,000 to 500,000 deaths each year. Vaccination is traditionally considered to be the best way to prevent influenza A. Yet because the Influenza A virus (IAV) is highly susceptible to antigenic drift and Antigenic shift, and because of the lag in vaccine production, this poses a significant challenge to vaccine effectiveness. Additionally, much information about the resistance of antiviral drugs, such as Oseltamivir and Baloxavir, has been reported. Therefore, the search for alternative therapies in the treatment of influenza is warranted. Recent studies have found that regulating the gut microbiota (GM) can promote the immune effects of anti-IAV via the gut-lung axis. This includes promoting IAV clearance in the early stages of infection and reducing inflammatory damage in the later stages. In this review, we first review the specific alterations in GM observed in human as well as animal models regarding IAV infection. Then we analyzed the effect of GM on host immunity against IAV, including innate immunity and subsequent adaptive immunity. Finally, our study also summarizes the effects of therapies using probiotics, prebiotics, or herbal medicine in influenza A on intestinal microecological composition and their immunomodulatory effects against IAV.

Activation of Antiviral Host Responses against Avian Influenza Virus and Remodeling of Gut Microbiota by rLAB Vector Expressing rIL-17A in Chickens

“…This study is in line with the previous findings, where IAV infection causes a marked alteration of gut microbiota mainly by decreasing the level of probiotic bacteria and increasing the level of pathogenic bacteria. 66 However, several shreds of evidence suggest that the intestinal microbiota composition in chickens impacts both local and systemic immune responses, influencing antiviral host defenses. 20,67 In addition to the indirect effect of microbiota in mediating local and systemic immune responses via interferons (IFNs), interleukins (ILs), and virus-specific antibodies, available reports also suggest the role of gut microbial metabolites, such as short-chain fatty acids, in the regulation of the antiviral immune responses in chickens.…”

Pediococcus pentosaceus MIANGUAN2 Alleviates Influenza Virus Infection by Modulating Gut Microbiota and Enhancing Short-Chain Fatty Acid Production

“…Recent studies have extensively investigated the involvement of the gut-lung axis mechanism in the effect of gut microbiota on pulmonary infection [ 17 , 18 ]. Some evidence indicates that gut microbiota-derived metabolites are potential mediators of the gut-lung axis that play a pivotal role in protecting the host against respiratory virus infections.…”