Neutrophil-Mimetic Apoptotic Vesicles as an Immunoengineering Strategy for Leishmaniasis Vaccination: A Preclinical Concept and Validation Roadmap

This preprint proposes a preclinical immunoengineering concept for leishmaniasis vaccination based on engineered neutrophil-mimetic apoptotic vesicles or apoptotic-cell-mimetic nanoparticles. The central hypothesis is that a delivery platform can deliberately exploit the phagocytic/efferocytic uptake routes associated with apoptotic neutrophil clearance, while overriding the normally tolerogenic “silent clearance” context through pattern-recognition receptor danger signaling. The proposed platform would carry Leishmania amastigote-stage antigens, such as A2, KMP-11, HASPB, selected multi-epitope constructs, or broader amastigote antigen mixtures, within or on biodegradable vesicular/nanoparticle carriers. The external surface would be tuned to promote uptake by macrophages and dendritic cells through phosphatidylserine-enriched apoptotic-cell/neutrophil-like mimicry. In parallel, the construct would include immunostimulatory adjuvant cues such as CpG ODN, Poly(I:C), MPL/GLA-like TLR4 agonism, or other PRR-agonist strategies to promote dendritic-cell maturation, IL-12 production, IFN-gamma-biased Th1/Tc1 polarization, and macrophage parasite-killing activity. The document presents the biological rationale, antigen and adjuvant logic, expected immune mechanism, candidate platform architecture, proposed in vitro and in vivo validation roadmap, control groups, measurable success criteria, and major failure modes. The manuscript is intended as an open hypothesis and research proposal for qualified immunologists, parasitologists, nanomedicine researchers, vaccine-adjuvant specialists, and veterinary leishmaniasis laboratories. It does not report original experimental data and does not make clinical efficacy or treatment claims.