This study describes the construction of a carrier-free self-assembled spherical peptide nanovaccine (termed MAP NVs) that co-delivers an adjuvant and an antigenic peptide. The Toll-like receptor 4 (TLR4) agonist monophosphoryl lipid A (MPLA) was covalently linked to a MUC1-targeting amino acid motif (Maa) to form MPLA-Maa monomer molecules. These MPLA-Maa monomers were then allowed to self-assemble with a Leu-His modified MUC1 epitope polypeptide (LMP) to form the final nanovaccine system.
The design purpose was to produce a self-carried formulation in which adjuvant and antigen are integrated into the same nanostructure, avoiding separate carrier materials, and to promote antigen presentation and T cell–mediated antitumor immunity.
MAP NVs were characterized for basic nanoparticle properties. The mean particle size was reported as 169.85 ± 4.05 nm, with a polydispersity index (PDI) of 0.308 ± 0.021. The surface charge (Zeta potential) measured −19.10 ± 1.00 mV. Stability testing in vitro indicated that the MAP NVs remained stable for more than 10 days. These parameters indicate a nanoscale spherical construct with moderate dispersity and a net negative surface charge under the measurement conditions described.
Cellular assays demonstrated that MAP NVs significantly promoted maturation and activation of dendritic cells. The nanovaccine increased secretion of tumor necrosis factor-α (TNF-α) in vitro, consistent with engagement of innate immune signaling via the MPLA component. Enhanced dendritic cell activation is presented as a central mechanism by which the nanovaccine improves downstream adaptive immune responses.
Antitumor activity was evaluated in the B16-MUC1 experimental melanoma model in mice. Treatment with MAP NVs produced notable antitumor effects: tumor growth was significantly inhibited, and survival of tumor-bearing mice was prolonged relative to control groups. The reported in vivo findings support efficacy of the co-delivery strategy in an established preclinical melanoma model bearing the MUC1 antigen.
Mechanistic analyses linked the observed tumor control to T cell–mediated immunity. MAP NVs effectively activated T cell responses, promoting proliferation of both CD4+ and CD8+ T cells. The formulation also induced the generation of CD8+ central memory T cells, an outcome associated with longer-term immune surveillance.
After antigen restimulation in treated animals, secretion levels of TNF-α and interferon-γ (IFN-γ) were significantly elevated, indicating that MAP NVs not only trigger acute effector responses but also establish immune memory capable of recall responses. These cytokine changes are consistent with enhanced Th1-type and cytotoxic T lymphocyte activity contributing to antitumor effects.
The authors conclude that a self-assembled, carrier-free spherical peptide nanovaccine co-delivering MPLA and a modified MUC1 peptide (LMP) was successfully constructed and characterized. By promoting dendritic cell activation and enhancing T cell immune responses, the MAP NVs system exhibited significant antitumor activity in a B16-MUC1 melanoma model and induced durable immune memory features such as CD8+ central memory T cells and elevated TNF-α and IFN-γ upon restimulation.
The work provides a technical approach and experimental basis for further development of nanovaccines against tumors, demonstrating that covalent adjuvant–antigen conjugation followed by self-assembly with an antigenic peptide can generate a stable, effective nanovaccine without an external carrier. Specific translational steps, safety data, dosing regimens, and broader efficacy across tumor types were not detailed in the abstract and therefore are not reported here.
Overall, the study highlights co-delivery of MPLA and MUC1-derived peptide within a self-carried nanoparticle as a promising strategy to elicit dendritic cell activation, robust CD4+ and CD8+ T cell responses, tumor growth inhibition, prolonged survival in a preclinical model, and induction of long-lasting immune memory.