Do we know the Th1/Th2/Th17 determinants of vaccine response?

Evaluation of: Kamath AT, Mastelic B, Christensen D et al. Synchronization of dendritic cell activation and antigen exposure is required for the induction of Th1/Th17 responses. J. Immunol. 188(10), 4828-4837 (2012). The determinants of Th1/Th2/Th17 responses elicited by vaccine formulations are largely undefined and are an intense area of research. Most of the present licensed alum-adjuvanted subunit vaccines fail to elicit Th1/Th17 immune responses, and Th2 antibody responses are weak and often require repeated immunizations. Moreover, such responses are not sufficient for eliminating intracellular pathogens. Th1 responses have been traditionally elicited by live-attenuated, vector-based or Toll-like receptor ligand-adjuvanted formulations for optimal stimulation of the innate immune system and immunomodulation. The linkage of adjuvant and antigen (Ag) physically, and/or in a formulation, is essential to overcome systemic effects of the adjuvant and elicit Th1/Th17 responses. The role of delivery systems for codelivery of adjuvant and Ag to the same dendritic cell has gained acceptance. The milieu in which dendritic cells process and present Ag to naive CD4(+) T cells determines their polarization into different subsets.