Biology subjects

Fleegle, J. D.

Publications and source records attributed to Fleegle, J. D..

4 recordsLinked to original sources

bioRxiv2026

In vitro dormancy models improve ability to predict treatment response in severe marmoset tuberculosis lesions

Tuberculosis lesions are structurally and physiologically heterogeneous, creating microenvironments that restrict antibiotic penetration and alter bacterial susceptibility. This heterogeneity remains a major impediment to shortening tuberculosis treatment, as it is difficult to predict which regimens will sterilize bacteria in these hard-to-treat lesion niches. Many in vitro systems and commonly used animal models fail to recapitulate the necrotic, caseous lesion pathology associated with treatment failure and relapse. Here, we show that resource-efficient in vitro assays engineered to mimic key lesion microenvironments, including those with lipid-rich, caseum-like matrices with controlled oxygenation and pH, generate drug-response metrics that predict lesion-level treatment responses in a non-human primate model. We stratified individual marmoset lesions by baseline 2-deoxy-2-[18F] fluoro-D-glucose ([18F] FDG) positron emission tomography/computed tomography (PET/CT) features, then quantified drug potency and interactions across three lipid-induced dormancy (LIDs) conditions under both equipotent and lesion pharmacokinetic-informed dosing schemes. LIDs-based and pharmacokinetic-informed measurements aligned more closely with treatment responses in severe lesions than conventional in vitro data and recapitulated interaction patterns consistent with known regimen performance. Integrating imaging-derived and in vitro features in multivariate, sequential computational models improved predictive accuracy over baseline imaging alone and identified a subset of informative in vitro metrics. Together, these results establish a scalable framework linking lesion-mimicking assays to lesion-specific outcomes, enabling earlier, more cost-effective prioritization of pre-clinical regimens aimed at sterilizing hard-to-treat tuberculosis lesions and shortening therapy.

molecular biology↗

bioRxiv2022

IL-10 suppresses T cell expansion while promoting tissue-resident memory cell formation during SARS-CoV-2 infection in rhesus macaques

The pro- and anti-inflammatory pathways that determine the balance of inflammation and viral control during SARS-CoV-2 infection are not well understood. Here we examine the roles of IFN{gamma} and IL-10 in regulating inflammation, immune cell responses and viral replication during SARS-CoV-2 infection of rhesus macaques. IFN{gamma} blockade tended to decrease lung inflammation based on 18FDG-PET/CT imaging but had no major impact on innate lymphocytes, neutralizing antibodies, or antigen-specific T cells. In contrast, IL-10 blockade transiently increased lung inflammation and enhanced accumulation of virus-specific T cells in the lower airways. However, IL-10 blockade also inhibited the differentiation of virus-specific T cells into airway CD69+CD103+ TRM cells. While virus-specific T cells were undetectable in the nasal mucosa of all groups, IL-10 blockade similarly reduced the frequency of total TRM cells in the nasal mucosa. Neither cytokine blockade substantially affected viral load and infection ultimately resolved. Thus, in the macaque model of mild COVID-19, the pro- and anti-inflammatory effects of IFN{gamma} and IL-10 have no major role in control of viral replication. However, IL-10 has a key role in suppressing the accumulation of SARS-CoV-2-specific T cells in the lower airways, while also promoting TRM at respiratory mucosal surfaces.

immunology↗

bioRxiv2021

CD4 T cells are rapidly depleted from tuberculosis granulomas following acute SIV co-infection

The HIV-mediated decline in circulating CD4 T cells correlates with increased the risk of active tuberculosis (TB)1-4. However, HIV/Mycobacterium tuberculosis (Mtb) co-infected individuals also have an increased incidence of TB prior to loss of CD4 T cells in blood3,5, raising the possibility that HIV co-infection leads to disruption of CD4 T cell responses at the site of lung infection before they are observed systemically. Here we used a rhesus macaque model of SIV/Mtb co-infection to study the early effects of acute SIV infection on CD4 T cells in pulmonary Mtb granulomas. Two weeks after SIV co-infection CD4 T cells were dramatically depleted from granulomas, before significant bacterial outgrowth, disease reactivation as measured by PET-CT imaging, or CD4 T cell loss in blood, airways, and lymph nodes. Mtb-specific CD4 T cells, CCR5-expressing, in granulomas were preferentially depleted by SIV infection. Moreover, CD4 T cells were preferentially depleted from the granuloma core and lymphocyte cuff relative to B cell-rich regions, and live imaging of granuloma explants showed that SIV co-infection reduced T cell motility. Thus, Mtb-specific CD4 T cells in pulmonary granulomas may be decimated before many patients even experience the first symptoms of acute HIV infection.

immunology↗

bioRxiv2021

Functional inactivation of pulmonary MAIT cells following 5-OP-RU treatment of non-human primates

Targeting MAIT cells holds promise for the treatment of different diseases and infections. We previously showed that treatment of Mycobacterium tuberculosis infected mice with 5-OP-RU, a major antigen for MAIT cells, expands MAIT cells and enhances bacterial control. Here we treated M. tuberculosis infected rhesus macaques with 5-OP-RU intratracheally but found no clinical or microbiological benefit in M. tuberculosis infected macaques. In fact, after 5-OP-RU treatment MAIT cells did not expand, but rather upregulated PD-1 and lost the ability to produce multiple cytokines, a phenotype resembling T cell exhaustion. Furthermore, we show that vaccination of uninfected macaques with 5-OP-RU+CpG instillation into the lungs also drives MAIT cell dysfunction, and PD-1 blockade during vaccination partly prevents the loss of MAIT cell function without facilitating their expansion. Thus, in rhesus macaques MAIT cells are prone to the loss of effector functions rather than expansion after TCR stimulation in vivo, representing a significant barrier to therapeutically targeting these cells.

immunology↗