The Host's Immune Responses Against Viruses: How We Know Our Own Bodies and How Our Bodies Defend Themselves from Viruses

Background: Viral infections pose a significant threat to health worldwide, requiring a coordinated and effective immune response to limit and eventually eliminate viral infection. The purpose of this review is to examine the different ways by which the immune system responds, both by innate and adaptive pathways, against viral infections, along with the mechanisms by which viruses evade host immune responses. Method: A systematic literature review was performed with an organized search through the following databases; PubMed, Scopus, Web of Science and ScienceDirect. The search was for studies published between 2015-2025. The final number of included articles was 45 as determined by established inclusion/exclusion criteria. Outcomes: The research results suggest that innate immunity is the first line of defense and that recognition patterns are detected by pattern recognition receptors (PRRs) such as Toll-like receptors (TLRs) and RIG-I like receptors (RLRs) resulting in the creation of Type I interferons and activation of antiviral- pathways. Adaptive immunity provides a more specific immune response via Cytotoxic T Cell (CTL), Helper T Cells (TH) and Antibody producing B Cells. Notwithstanding these immune responses, many viruses have evolved to evade detection with numerous methods, including antigenic variation, immune suppression and latency. In conclusion, host immune responses during a viral infection involve many different and complex interactions between all of the different components of the immune system. Understanding host immunity and immune system interactions during a viral infection is critical for developing effective vaccines and antiviral therapies. There is also a need for further research into the development of immunotherapies and targeting the virus' ability to escape from host immune defenses.