Minipigs as a neonatal animal model for tuberculosis vaccine efficacy testing

Many vaccines against childhood diseases are administered early after birth, but vaccine development studies frequently test efficacy in adult rather than in neonatal animal models. In countries with endemic tuberculosis (TB), Bacillus Calmette-Guerin (BCG) is administered as part of the neonatal vaccine regimen because it prevents against the disseminated form of TB in children, although it has variable efficacy against pulmonary TB. Several promising new vaccines against TB are currently being tested in adult animal models. Here we evaluated neonatal piglets as an animal model to test vaccine efficacy. For this purpose, minipigs were vaccinated or not with BCG 48 h after birth and their immune response followed longitudinally until adolescence. We characterized the memory and activation phenotype of T cells, cytokine profile, and monocyte activation in response to BCG stimulation from 4 weeks of age into adolescence- age of 24 weeks. Immunological responses in vaccinated and non-vaccinated animals were further monitored upon infection with a low dose exposure to Mycobacterium tuberculosis strain HN878 via the aerosol route. Comparing the immunological response elicited by BCG vaccination in minipigs vs similar studies in infants, suggest that minipigs have the potential to serve as an effective neonatal animal model for vaccine development.