CD2 and TLR4 agonist
As adaptive cellular immune response, saponins interact directly with the CD2 surface receptor of T cells directly promoting their activation. QS-21 is identified as a potential TLR4 agonist.
Humoral and Cellular response
Saponins are capable of inducing antigen cross-presentation by professional antigen-presenting cells, promoting presentation to CD8+ T cells via MHC-I and favoring the cytotoxic response. These mechanisms of action drive both humoral and cellular responses.
Innate and adaptive response
Saponin adjuvants generate a biological effect, in both innate cellular and adaptive immune responses. Saponins are an immunostimulatory adjuvant. Saponins induce infiltration of pro-inflammatory cells, release of DAMPs at the site of inoculation and activation of migratory and resident lymph node antigen presenting cells.
