A Mathematical Modeling Framework for a Periodic Subcutaneous Tolerogenic Immune Training Vaccine (LSTIV) to Promote Donor-Specific Tolerance in Solid Organ Transplantation: A Hypothesis-Generating Theoretical Study with Explicit Assumptions and Limitations

This manuscript proposes a conceptual, hypothesis-generating framework for a periodic subcutaneous tolerogenic immune training vaccine (LSTIV) administered monthly or quarterly. The LSTIV is hypothesized to support donor-specific immune tolerance in solid organ transplantation by promoting the expansion and stabilization of donor-specific regulatory T cells (Tregs), tolerogenic dendritic cells (tolDCs), and associated peripheral tolerance circuits. We present a multi-compartment ordinary differential equation (ODE) model of immune-graft dynamics incorporating periodic forcing, calibrated using parameter ranges reported in peer-reviewed literature. Numerical simulations (using scipy.integrate.solve_ivp with adaptive stepping and positivity constraints), global sensitivity analysis (Monte Carlo sampling, partial rank correlation coefficients, Sobol indices), Bayesian uncertainty quantification, and explicit falsifiability criteria are included. Under the stated model assumptions, periodic LSTIV administration is predicted to support a Treg-to-effector T cell (Teff) ratio exceeding 8--10 and a graft health index G(730) approaching 0.90 (monthly dosing) versus approximately 0.25 (no intervention). Predictions are compared qualitatively with observational registry data (OPTN/SRTR). A dedicated limitations section acknowledges model simplifications, parameter uncertainty, and the gap between theoretical modeling and clinical translation. All code, derivations, and data are provided for reproducibility. This work is intended as a theoretical exploration to generate testable hypotheses, not as proof of clinical efficacy.