The Diversity Outbred Mouse Population Is an Improved Animal Model of Vaccination against Tuberculosis That Reflects Heterogeneity of Protection

Abstract

Many studies of Mycobacterium tuberculosis infection and immunity have used mouse models. However, outcomes of vaccination and challenge with M. tuberculosis in inbred mouse strains do not reflect the full range of outcomes seen in people. Previous studies indicated that the novel Diversity Outbred (DO) mouse population exhibited a spectrum of outcomes after primary aerosol infection with M. tuberculosis. Here, we demonstrate the value of this novel mouse population for studies of vaccination against M. tuberculosis aerosol challenge. Using the only currently licensed tuberculosis vaccine, we found that the DO population readily controlled systemic Mycobacterium bovis BCG bacterial burdens and that BCG vaccination significantly improved survival across the DO population upon challenge with M. tuberculosis. Many individual DO mice that were vaccinated with BCG and then challenged with M. tuberculosis exhibited low bacterial burdens, low or even no systemic dissemination, little weight loss, and only minor lung pathology. In contrast, some BCG-vaccinated DO mice progressed quickly to fulminant disease upon M. tuberculosis challenge. Across the population, most of these disease parameters were at most modestly correlated with each other and were often discordant. This result suggests the need for a multiparameter metric to better characterize “disease” and “protection,” with closer similarity to the complex case definitions used in people. Taken together, these results demonstrate that DO mice provide a novel small-animal model of vaccination against tuberculosis that better reflects the wide spectrum of outcomes seen in people. IMPORTANCE We vaccinated the Diversity Outbred (DO) population of mice with BCG, the only vaccine currently used to protect against tuberculosis, and then challenged them with M. tuberculosis by aerosol. We found that the BCG-vaccinated DO mouse population exhibited a wide range of outcomes, in which outcomes in individual mice ranged from minimal respiratory or systemic disease to fulminant disease and death. The breadth of these outcomes appears similar to the range seen in people, indicating that DO mice may serve as an improved small-animal model to study tuberculosis infection and immunity. Moreover, sophisticated tools are available for the use of these mice to map genes contributing to control of vaccination. Thus, the present studies provided an important new tool in the fight against tuberculosis.

Automatic discovery of clinically interpretable imaging biomarkers for Mycobacterium tuberculosis supersusceptibility using deep learning

“…We showed that supersusceptible DO mice develop pulmonary TB with large necrotizing granulomas and abundant M.tb bacilli, while those that survive longer develop non-necrotic lymphocyte-rich granulomas. Published elsewhere, we confirmed that DO mice are not immune deficient or highly susceptible to other mycobacteria, and they generate antigenspecific immunity against M.tb [16,23,24]. Together, these results support our conclusion that DO mice are a valuable animal model of TB.…”

Aging, But Not Sex and Genetic Diversity, Impacts the Pathobiology of Bacterial Endophthalmitis

“…In a longitudinal study, J:DO mice were found to be more susceptible to Mycobacterium tuberculosis, as they exhibited increased lung bacterial load and pathology and died 80 days post-infection, whereas B6 mice survived until 113 days. 47 Although no sex-based differences were observed in innate responses, S. aureusinfected J:DO mouse eyes had slightly elevated levels of IL-1β and CXCL2/MIP2 as compared to C57BL/6 mice, whereas TNF-α and IL-6 levels were similar. In systemic bacterial infections, diversity outbred mice have been shown to evoke a strong chemokine response.…”

“…The J:DO founders were derived from eight inbred strains, including traditional laboratory strains such as C57BL/6 and A/J, as well as three wild-derived mice strains (CAST/EiJ, PWK/PhJ, and WSB/EiJ) through collaborative cross. [45][46][47] As these mice have been used to account for genetic diversity in bacterial and viral infections, 46,47 S. aureus endophthalmitis was induced in both male and female J:DO mice (6-8 weeks old). Our time-course study revealed that, like C57BL/6 mice, J:DO mice developed severe endophthalmitis resulting in a time-dependent increase in corneal haze, anterior chamber opacity, and hypopyon (Fig.…”

Tuberculosis biomarkers discovered using Diversity Outbred mice

“…One third of DO mice are supersusceptible (SS) to Mtb, developing early-onset disease within 8 weeks of aerosol infection by ~25 bacilli, significantly reducing survival compared to age-and sex-matched non-infected DO mice or to Mtb-infected C57BL/6J inbred mice ( Figure 1A). The SS phenotype is consistent across sexes, institutions, and aerosol infection methods 11,25 .…”

“…Disease onset in SS DO mice began as early as 4 days afterMtb infection and peaked at 18 days post-infection (C).Immune deficiency does not explain early-onset TB in the DO population. DO mice generate Mtb antigen specific TH1 immunity, respond to M. bovis BCG vaccination without developing BCGosis11,16,25 and generate TH2 and TH17 immune mediators (Supplemental Figures). Our prior work identified three neutrophil chemokines (CXCL1, CXCL2, CXCL5) that diagnosed SS DO mice with modest accuracy11 .…”