Provided are variants of saponins that are found in Quillaja saponaria (QS) Molina tree bark that are chemically modified to distinguish them from naturally occurring parent saponins. The modified saponins have increased adjunctive activity compared to the unmodified parent saponins. Defined structures allow for comparisons of the modifying groups with respect to their respective adjunct activity and permit characterized vaccine formulations that have one or more defined saponins.

Disclosed herein are compounds of the formulas (A-I) and (B) that may be useful for activating invariant natural killer T (iNKT) cells. According to certain disclosed embodiments activation of iNKT cells induces production of one or more cytokines, such as IFN, IL-2, IL-4, IL-6 and TNF, and results in reduction of senescent cells.

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Disclosed herein are compounds of the formulas (A-I) and (B) that may be useful for activating invariant natural killer T (iNKT) cells. According to certain disclosed embodiments activation of iNKT cells induces production of one or more cytokines, such as IFN, IL-2, IL-4, IL-6 and TNF, and results in reduction of senescent cells.

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