Airway T cells are a correlate of i.v. Bacille Calmette-Guerin-mediated protection against tuberculosis in rhesus macaques.

Bacille Calmette-Guerin (BCG), the only approved Mycobacterium tuberculosis (Mtb) vaccine, provides limited durable protection when administered intradermally. However, recent work revealed that intravenous (i.v.) BCG administration yielded greater protection in macaques. Here, we perform a dose-ranging study of i.v. BCG vaccination in macaques to generate a range of immune responses and define correlates of protection. Seventeen of 34 macaques had no detectable infection after Mtb challenge. Multivariate analysis incorporating longitudinal cellular and humoral immune parameters uncovered an extensive and highly coordinated immune response from the bronchoalveolar lavage (BAL). A minimal signature predicting protection contained four BAL immune features, of which three remained significant after dose correction: frequency of CD4 T cells producing TNF with interferon γ (IFNγ), frequency of those producing TNF with IL-17, and the number of NK cells. Blood immune features were less predictive of protection. We conclude that CD4 T cell immunity and NK cells in the airway correlate with protection following i.v. BCG. [Display omitted] • An i.v. Bacille Calmette-Guerin (BCG) dose-ranging study generated a range of protection against tuberculosis in macaques • Immune measurements from blood and BAL were integrated for correlates analysis • Multivariate analysis of BAL features revealed a highly coordinated immune network • Tuberculosis-specific CD4 Th1/Th17 and NK cells in the airway correlated with protection Vaccination with intravenous Bacille Calmette-Guerin (i.v. BCG) protects macaques from tuberculosis. Using a dose-ranging i.v. BCG strategy, Darrah, Zeppa, Wang, et al. elicited graded immune responses and 50% protection in macaques. Multivariate analysis of longitudinal cellular and humoral parameters identified antigen-specific CD4 T cells and NK cells in the airway as strong correlates of protection. [ABSTRACT FROM AUTHOR]