The human immune system undergoes numerous changes with age, collectively termed as immunosenescence. These alterations impact thymic activity, T cell function, B cell function, innate immune response, inflammation, cytokine production, immune surveillance, vaccine responsiveness, immunity balance, and the gut microbiome. An understanding of these changes helps devise strategies to maintain immune health in older individuals and minimize susceptibility to infections and age-related diseases.

The gut microbiome, a community of trillions of microorganisms in the gastrointestinal tract, plays a fundamental role in shaping the human immune system. These microbes contribute to immune development, activate the innate immune system, produce anti-inflammatory substances, enhance gut barrier function, offer antimicrobial defense, influence systemic immune responses and regulate the adaptive immune system. Imbalances in the gut microbiome can result in autoimmune diseases and allergies, affirming the indispensable role of the microbiome in overall immune health.

Basic research helps develop vaccines and immunotherapies by identifying antigen targets, designing vaccines that mimic natural infections and mRNA-based ones, and creating adjuvants to enhance immune responses. Insights into immune dysregulations aid in developing immunotherapies and monoclonal antibodies for various diseases. The understanding of varied immune responses also supports the development of personalized immunotherapies.