Tuberculosis Imaging Program

National Institute Of Allergy And Infectious Diseases

Investigators

Linked publications, trials & patents

Abstract

The major activities of this research project in the past have centered around using our optimized methods and procedures for imaging rhesus macaques, NZW rabbits, and common marmosets on PET/CT scanners while conducting a variety of chemotherapy and basic immunology experiments in Mtb models. We have also optimized the imaging of mice on the LFER scanner to fulfill the need in the Tuberculosis Research Section (TRS), but because of the resolution and speed of the unit, it is not ideal for mice. The experiments in 2023 included finishing up short term Mtb infections of unvaccinated rhesus macaques with the Vaccine Research Center (VRC) as well as rabbit, marmoset, and mouse infections with Mtb with TRS to examine efficacy or penetration of potential anti-tubercular compounds into MTB lesions. Experiments involving Sars-Cov-2 infection of macaques was also completed with the T-cell biology section (TBS) and members of the LID. As the ABSL-3 closure has extended significantly, no new experiments have started although many are planned. When possible, we applied automated image analysis methods that segregate low- and high-density ranges using a whole lung technique. We have working with multiple extramural partners during this time to assist in the analysis of their Mtb-infection models imaging data. Some specific projects where we contributed and are now published are mentioned below: We assisted TRS in investigating the myxobacterial antibiotic myxovalargin by conducting tolerability studies in mice. Myxovalargin was not tolerable in MTB-infected mice although nave mice survived short term exposure. Myxovalargin killed MTB through inhibiting translation initiation by occluding the ribosome exit. This unique mechanism of action seemed to be a viable target, but the compound needs improvement to be used in vivo (PMID 36603206). In collaboration with TRS and investigators at Rutgers University, we continued to use rabbits and MTB lesions from the rabbit model to elucidate the drug penetration into caseum as a mimic of human lesions and drug activity in this nutrient-limiting hypoxic condition. In 2023, we specifically examined Bedaquiline (BDQ) and 2 newer diarylquinolines TBAJ876 and TBAJ587, that target the MTB adenosine triphosphate (ATP) synthase enzyme in MTB infected rabbits and found that the new drug candidates had more rapid penetration and faster wash-out periods than BDQ. One of these achieved high enough penetration into the center of large (3-5 cm) lesions to exceed the concentration necessary to kill at least 90% of resident MTB in the 2 week assay, while the approved drug BDQ and the other compounds diffusion was inadequate in large lesions. Both of the new diarylquinolines exhibited superior bactericidal activity against caseum-resident bacteria than BDQ and were reported to be more active in regimens as substitutes for BDQ (PMID 37017524). In Sars-CoV-2 investigations with the RNA Viruses Section of LID and TBS, they used rhesus macaques to demonstrate the activity of a live-attenuated parainfluenza-virus-vectored vaccine candidate expressing SARS-CoV-2 prefusion-stabilized spike (S) protein (B/HPIV3/S-6P) (PMID: 3642362). As we assisted the team with clinical assays of the infected macaques as they demonstrated that SARS-CoV-2 replication was undetectable in airways and lung tissues of immunized macaques. The immunized macaques made S-specific antibodies which efficiently neutralized SARS-CoV-2 variants of concern of alpha, beta, and delta lineages and induced systemic and pulmonary S-specific CD4+ and CD8+ T cell responses, including tissue-resident memory cells in the lungs.