Tripping on Acid: Trans-Kingdom Perspectives on Biological Acids in Immunity and Pathogenesis
Figure 2
Acid's role in initiating adaptive immunity.
An antigen-presenting cell activated by innate PRR will present peptide antigen generated in acidic vesicles to a helper T cell via MHC class II. Activated by this presentation of specific antigen, the helper T cell can then mediate many different immune effector functions, depending on the subtype of helper CD4+ T cell, context, and signals from the APC. Five such major immune effector pathways are suggested here.