BCG vaccination with adjunctive APRIL immunotherapy reduces tuberculosis relapse in mice.

Bacille Calmette-Guérin (BCG) provides limited protection against tuberculosis relapse. We investigated whether adjunctive immunotherapy targeting B cells enhances BCG-mediated protection in a murine model of latent tuberculosis. While BCG alone had modest effects, adjunctive immunotherapy with recombinant APRIL significantly reduced relapse. Protection was associated with selective remodeling and activation of marginal-zone B cell compartments, whereas effects on T cell populations were comparatively modest. These findings support further investigation of B cell-targeted immunomodulation to improve durable immune control and reduce tuberculosis relapse.