CD38 Peptide Vaccine Reverses Aging Signs in Mice With a Few Doses
A new vaccination strategy targeting CD38 improved physical function, cognition, metabolism, and NAD+ levels in aging mice — with just a few injections.
Summary
Researchers at Tsinghua University developed a peptide vaccine targeting CD38, a protein that accumulates with age and depletes NAD+. Administered to middle-aged mice, the vaccine induced strong antibody and T-cell responses, selectively eliminated CD38+ myeloid cells in the spleen, improved grip strength and cognitive performance, enhanced glucose tolerance and oxygen consumption, and boosted liver NAD+/NADH ratios. It also reduced senescent cell burden and senescence-associated gene expression in the liver. Unlike daily supplements such as NMN or metformin, this vaccine approach requires only a few doses while delivering lasting immune-mediated benefits, representing a promising new anti-aging strategy.
Detailed Summary
Aging drives NAD+ depletion, metabolic dysfunction, and cellular senescence — problems that currently require daily pharmacological intervention to address. Vaccination offers a fundamentally different approach: train the immune system once (or a few times) to continuously suppress a disease-causing target. This study explores whether a peptide vaccine against CD38, the enzyme primarily responsible for age-related NAD+ decline, could ameliorate aging phenotypes in mice.
The researchers screened three candidate epitopes from the CD38 protein and identified the N-terminal sequence ANYEFSQV (amino acids 2–9) as the most immunogenic. This peptide, conjugated to keyhole limpet hemocyanin (KLH) and formulated with alum adjuvant, generated the highest antibody titers and avidity indices (>60%) in both young and aged mice. A prime-boost vaccination protocol was then applied to C57BL/6J mice starting at 12 months of age, with healthspan assessments conducted between 15 and 20 months.
Vaccinated mice showed robust and sustained IgG antibody responses and a strong T-cell immune profile, with significantly elevated IFN-γ-secreting (Th1) and IL-4-secreting (Th2) splenocytes upon CD38 peptide stimulation. Critically, flow cytometry revealed selective depletion of CD38+ myeloid cells (CD11b-hi CD11c-mid) in the spleen — the cell population previously implicated in driving age-associated NAD+ decline — without broadly disrupting other immune cell subsets. CD38+ myeloid cell proportions in liver tissue also trended lower in vaccinated animals.
Functionally, vaccinated mice demonstrated improved grip strength, enhanced balance beam performance, and better spatial memory in Morris water maze tests compared to KLH controls. Metabolically, they showed improved glucose tolerance (IPGTT), increased oxygen consumption and energy expenditure in metabolic cage studies, and reduced adiposity markers. Liver tissue analysis revealed a significantly elevated NAD+/NADH ratio, decreased senescent cell counts (SA-β-gal staining), and reduced mRNA expression of senescence-associated secretory phenotype (SASP) genes including p21, p16, IL-6, and MMP3. Proteomic profiling of liver tissue confirmed enhanced oxidative phosphorylation pathway activity and suppressed glycolysis — consistent with a metabolically younger phenotype.
These findings position CD38-targeting vaccination as a viable multi-benefit anti-aging strategy. By harnessing the immune system's memory to continuously deplete CD38+ myeloid cells, the vaccine mimics the benefits of CD38 inhibitors (like 78c) and anti-CD38 antibodies (like daratumumab) but with greater durability and fewer doses. The approach is mechanistically distinct from senolytics and previous anti-aging vaccines (CD153, GPNMB) by targeting NAD+ metabolism upstream rather than removing senescent cells directly.
Key Findings
- CD38 peptide ANYEFSQV generated the highest antibody titers and avidity (>60%) in both young and aged mice.
- Vaccination selectively depleted CD38+ myeloid cells in the spleen, the key drivers of age-related NAD+ decline.
- Vaccinated mice showed improved grip strength, balance, and spatial memory versus controls at 18–20 months.
- Liver NAD+/NADH ratio increased significantly; senescent cell counts and SASP gene expression decreased.
- Metabolic cage analysis showed enhanced oxygen consumption and reduced glycolysis, consistent with rejuvenated metabolism.
Methodology
C57BL/6J mice received subcutaneous prime-boost injections of KLH-conjugated CD38 peptide with alum adjuvant starting at 12 months old; healthspan was assessed between 15–20 months. Endpoints included ELISA antibody titers, flow cytometry immunophenotyping, metabolic cage analysis, IPGTT, Morris water maze, liver proteomics, LC-MS NAD+/NADH quantification, and senescence biomarkers (SA-β-gal staining and qPCR of SASP genes).
Study Limitations
The study was conducted exclusively in male C57BL/6J mice, limiting generalizability to females and other species. The vaccine's effects on lifespan extension were not assessed, and the optimal dosing schedule for humans remains unknown. Potential off-target immune effects on CD38-expressing plasma cells and NK cells were not fully characterized.
Enjoyed this summary?
Get the latest longevity research delivered to your inbox every week.