IF a sequential senolytic-priming immunotherapy protocol—two cycles of dasatinib (5 mg/kg) plus quercetin (50 mg/kg) via oral gavage administered at weeks −4 and −2 (prior to vaccination), followed immediately by GPNMB peptide vaccination (50 μg with AddaVax adjuvant, prime at week 0, boosts at weeks 2 and 4)—is administered to naturally aged female and male C57BL/6J mice (20–22 months), targeting senescent cell clearance across liver, kidney cortex, visceral adipose tissue, and aortic endothelium,

THEN at week 8 post-vaccination initiation, the sequential combination arm will achieve:

• ≥40% reduction in p16Ink4a+ cell burden across ≥3 tissue compartments (vs. vehicle), exceeding the ≥25% threshold set by either monotherapy alone,
• Anti-GPNMB IgG titers >1:4000 by ELISA (at least 2-fold higher than vaccination-alone controls),
• Significantly elevated NK cell degranulation (CD107a+) and granzyme B secretion by flow cytometry compared to either monotherapy,
• ≥35% reduction in circulating SASP factors (IL-6, MCP-1, PAI-1) sustained to week 8,

measured by p16Ink4a immunohistochemistry (automated QuPath digital quantification), serum ELISA for IgG titers and SASP markers, and flow cytometry of splenic and peripheral NK cells,

BECAUSE of the following step-by-step causal chain:

1. SASP-driven immune suppression limits vaccine efficacy in aged hosts. In 20–22-month-old C57BL/6J mice, the abundant SASP burden—characterized by elevated IL-6, MCP-1, TGF-β, and PAI-1—creates a chronic low-grade inflammatory milieu that functionally exhausts NK cells, suppresses their degranulation capacity (CD107a), and impairs dendritic cell antigen presentation, directly constraining the humoral and cellular immune response to any peptide vaccination (Suda et al., Nature Aging, 2021, as cited in the evidence set). [SPECULATIVE: the mechanistic link between SASP-mediated NK exhaustion and impaired anti-GPNMB IgG titering in aged mice has not been directly demonstrated but is supported by established NK cell immunosenescence literature.]

2. D+Q pre-treatment reduces bulk SASP and senescent cell burden pharmacologically, independent of host immune function. The combination of dasatinib (tyrosine kinase/dependence receptor inhibition) and quercetin (BCL-2/BCL-xL antagonism) disrupts SCAP networks in senescent cells across liver, kidney cortex, and visceral adipose, rapidly reducing p16Ink4a+ cell burden by ~30–50% and substantially lowering circulating IL-6 and MCP-1 within days of administration (as described in the evidence set referencing Xu et al., Nature Medicine, 2018; Hickson et al., Cell Metabolism, 2019). This clearance is immune-independent, functioning even in the immunosenescent aged host.

3. SASP reduction by D+Q pre-treatment rescues NK cell functional competence. By lowering the chronic SASP-driven cytokine environment prior to vaccination, D+Q pre-treatment is predicted to restore NK cell surface NKG2D receptor density, improve CD10...

SENS category: GlycoSENS