Help is on the way: critical roles of CD4 + T cells in infection and vaccination.

The July 2023 issue contains a Special Feature about CD4 T cells in infection and vaccination. CD4 T helper cells are composed of many specialized subsets that play critical roles in immune memory. These cells have been somewhat overshadowed in the infectious disease and vaccination literature by their CD8 counterparts and B cells/antibodies, which have been easier to study with available techniques. Therefore, we designed this issue to shine a light on some of the latest knowledge on how CD4 T cells contribute to protective immunity. This Special Feature includes both original research and review articles on techniques to study CD4 T-cell subsets and their roles in influenza A virus or human papilloma virus infection, sepsis and following vaccination to severe acute respiratory syndrome coronavirus 2. This collection highlights how new techniques are enabling rapid knowledge gain on how these cells underpin key aspects of the generation of effective immune responses, information that will be essential for the treatment and prevention of infectious diseases.