Protocol for analyzing BCG-induced trained immunity in murine bone marrow-derived macrophages.

Bacillus Calmette-Guérin (BCG), the only licensed tuberculosis vaccine, provides non-specific protection against non-tuberculosis diseases that is mediated by trained immunity, a functional reprogramming mediated by innate immune memory. Here, we present a protocol for analyzing BCG-induced trained immunity in murine bone marrow-derived macrophages (BMDMs). We describe steps for preparing BCG single bacterial suspensions, isolating BMDM cells, and the training process. This protocol can assist researchers to conveniently utilize BMDM cells to study trained immunity. For complete details on the use and execution of this protocol, please refer to Xu et al.1.

Establishment of an in vitro model of monocyte-like THP-1 cells for trained immunity induced by bacillus Calmette-Guérin.

BACKGROUND: Mycobacteria bloodstream infections are common in immunocompromised people and usually have disastrous consequences. As the primary phagocytes in the bloodstream, monocytes and neutrophils play critical roles in the fight against bloodstream mycobacteria infections. In contrast to macrophages, the responses of monocytes infected with the mycobacteria have been less investigated. RESULTS: In this study, we first established a protocol for infection of non-adherent monocyte-like THP-1 cells (i.e. without the differentiation induced by phorbol 12-myristate 13-acetate (PMA) by bacillus Calmette-Guérin (BCG). Via the protocol, we were then capable of exploring the global transcriptomic profiles of non-adherent THP-1 cells infected with BCG, and found that NF-κB, MAPK and PI3K-Akt signaling pathways were enhanced, as well as some inflammatory chemokine/cytokine genes (e.g. CCL4, CXCL10, TNF and IL-1ß) were up-regulated. Surprisingly, the Akt-HIF-mTOR signaling pathway was also activated, which induces trained immunity. In this in vitro infection model, increased cytokine responses to lipopolysaccharides (LPS) restimulation, higher cell viability, and decreased Candida albicans loads were observed. CONCLUSIONS: We have first characterized the transcriptomic profiles of BCG-infected non-adherent THP-1 cells, and first developed a trained immunity in vitro model of the cells.

Multi-omics analysis reveals that linoleic acid metabolism is associated with variations of trained immunity induced by distinct BCG strains.

Trained immunity is one of the mechanisms by which BCG vaccination confers persistent nonspecific protection against diverse diseases. Genomic differences between the different BCG vaccine strains that are in global use could result in variable protection against tuberculosis and therapeutic effects on bladder cancer. In this study, we found that four representative BCG strains (BCG-Russia, BCG-Sweden, BCG-China, and BCG-Pasteur) covering all four genetic clusters differed in their ability to induce trained immunity and nonspecific protection. The trained immunity induced by BCG was associated with the Akt-mTOR-HIF1α axis, glycolysis, and NOD-like receptor signaling pathway. Multi-omics analysis (epigenomics, transcriptomics, and metabolomics) showed that linoleic acid metabolism was correlated with the trained immunity-inducing capacity of different BCG strains. Linoleic acid participated in the induction of trained immunity and could act as adjuvants to enhance BCG-induced trained immunity, revealing a trained immunity-inducing signaling pathway that could be used in the adjuvant development.

Effectiveness of Histopathological Examination of Ultrasound-guided Puncture Biopsy Samples for Diagnosis of Extrapulmonary Tuberculosis.

Objective: To evaluate the diagnostic value of histopathological examination of ultrasound-guided puncture biopsy samples in extrapulmonary tuberculosis (EPTB). Methods: This study was conducted at the Shanghai Public Health Clinical Center. A total of 115 patients underwent ultrasound-guided puncture biopsy, followed by MGIT 960 culture (culture), smear, GeneXpert MTB/RIF (Xpert), and histopathological examination. These assays were performed to evaluate their effectiveness in diagnosing EPTB in comparison to two different diagnostic criteria: liquid culture and composite reference standard (CRS). Results: When CRS was used as the reference standard, the sensitivity and specificity of culture, smear, Xpert, and histopathological examination were (44.83%, 89.29%), (51.72%, 89.29%), (70.11%, 96.43%), and (85.06%, 82.14%), respectively. Based on liquid culture tests, the sensitivity and specificity of smear, Xpert, and pathological examination were (66.67%, 72.60%), (83.33%, 63.01%), and (92.86%, 45.21%), respectively. Histopathological examination showed the highest sensitivity but lowest specificity. Further, we found that the combination of Xpert and histopathological examination showed a sensitivity of 90.80% and a specificity of 89.29%. Conclusion: Ultrasound-guided puncture sampling is safe and effective for the diagnosis of EPTB. Compared with culture, smear, and Xpert, histopathological examination showed higher sensitivity but lower specificity. The combination of histopathology with Xpert showed the best performance characteristics.

Advances in protein subunit vaccines against tuberculosis.

Tuberculosis (TB), also known as the "White Plague", is caused by Mycobacterium tuberculosis (Mtb). Before the COVID-19 epidemic, TB had the highest mortality rate of any single infectious disease. Vaccination is considered one of the most effective strategies for controlling TB. Despite the limitations of the Bacille Calmette-Guérin (BCG) vaccine in terms of protection against TB among adults, it is currently the only licensed TB vaccine. Recently, with the evolution of bioinformatics and structural biology techniques to screen and optimize protective antigens of Mtb, the tremendous potential of protein subunit vaccines is being exploited. Multistage subunit vaccines obtained by fusing immunodominant antigens from different stages of TB infection are being used both to prevent and to treat TB. Additionally, the development of novel adjuvants is compensating for weaknesses of immunogenicity, which is conducive to the flourishing of subunit vaccines. With advances in the development of animal models, preclinical vaccine protection assessments are becoming increasingly accurate. This review summarizes progress in the research of protein subunit TB vaccines during the past decades to facilitate the further optimization of protein subunit vaccines that may eradicate TB.

Diagnosis of extrapulmonary tuberculosis by ultrasound-guided biopsy: A retrospective comparison study.

Objective: To compare the diagnostic performance of laboratory assays on the ultrasound-guided core needle biopsy samples for diagnosis of extra-pulmonary tuberculosis (EPTB) in HIV-positive and HIV-negative patients. Methods: A total of 217 patients suspected to have EPTB underwent lesion biopsy from 2017 to 2020. Results of laboratory tests on the biopsy and non-biopsy samples were collected with clinical data for retrospective analysis of test utility. The calculated diagnostic accuracy of the tests was stratified according to the specimen types and HIV status. Results: The cohort contained 118 patients with a final positive diagnosis of extrapulmonary tuberculosis (EPTB group, 54.4%) and 99 finally diagnosed as without TB (non-EPTB group, 45.6%). The risk factor for EPTB was HIV co-infection (OR 2.22, 95% CI 1.17-4.28, p = 0.014). In biopsy samples, GeneXpert (Xpert) showed higher sensitivity (96.6% [91.6-98.7], p < 0.0001) than culture (56.1% [47.0-64.9]). Regardless of HIV status, Xpert had the highest sensitivity (>95%) and specificity (nearly 100%) of any methods. In non-biopsy samples, only T-SPOT.TB (T-SPOT) showed higher sensitivity than culture (90.9% [62.3-99.5] vs 35.3% [17.3-58.7], p = 0.0037). Furthermore, the sensitivities of Xpert were lower in non-biopsy samples (60.0% [23.1-92.9], p = 0.022) than in biopsy samples (100% [86.7-100]). Even in smear-negative biopsy samples, Xpert still had higher sensitivity than culture and retained high specificity (100% [95.7-100]). Conclusion: Superior performance of Xpert in diagnosing EPTB was observed regardless of HIV status and specimen types. Nevertheless, the biopsy samples still substantially facilitated the accurate diagnosis of extrapulmonary tuberculosis.

A two-dose optimum for recombinant S1 protein-based COVID-19 vaccination.

BACKGROUND: Recombinant protein subunit vaccination is considered to be a safe, fast and reliable technique when combating emerging and re-emerging diseases such as coronavirus disease 2019 (COVID-19). Typically, such subunit vaccines require the addition of adjuvants to attain adequate immunogenicity. AS01, which contains adjuvants MPL and saponin QS21, is a liposome-based vaccine adjuvant system that is one of the leading candidates. However, the adjuvant effect of AS01 in COVID-19 vaccines is not well described yet. METHODS: In this study, we utilized a mixture of AS01 as the adjuvant for an S1 protein-based COVID-19 vaccine. RESULTS: The adjuvanted vaccine induced robust immunoglobulin G (IgG) binding antibody and virus-neutralizing antibody responses. Importantly, two doses induced similar levels of IgG binding antibody and neutralizing antibody responses compared with three doses and the antibody responses weakened only slightly over time up to six weeks after immunization. CONCLUSION: These results suggested that two doses may be enough for a clinical vaccine strategy design using MPL & QS21 adjuvanted recombinant protein, especially in consideration of the limited production capacity of COVID-19 vaccine in a public health emergency.

Mycobacterium tuberculosis Rv3628 isan effective adjuvant via activationof dendritic cells for cancer immunotherapy.

Tumor antigens (Ags) are weakly immunogenic and elicit inadequate immune responses, thus induction of antigen-specific immune activation via the maturation of dendritic cells (DCs) is a strategy used for cancer immunotherapy. In this study, we examined the effect of Rv3628 from Mycobacterium tuberculosis (Mtb) on activation of DCs and anti-tumor immunity in vivo. Intravenous injection of mice with Rv3628 promoted DC activation of spleen and lymph nodes. More importantly, Rv3628 also induced activation of DCs and enhanced Ag presentation in tumor-bearing mice. In mice bearing ovalbumin (OVA)-expressing tumors, combination treatment with Rv3628 and OVA peptide promoted OVA-specific T cell activation and accumulation of interferon (IFN)-γ and tumor necrosis factor (TNF)-α-producing OT-I and OT-II cells in tumor-draining lymph nodes. Moreover, three different tumor Ags in three different tumor models showed enhanced anti-tumor activity with Rv3628 as adjuvant, including inhibition of growth of OVA-expressing B16 melanoma, CT26 carcinoma, and B16 melanoma tumors, and a synergistic effect with anti-programmed cell death protein 1 (PD-1) antibody treatment. Additionally, potential application against human tumors was indicated by similar activation of human peripheral blood DCs by Rv3628. Taken together, these data demonstrate that Rv3628 could be an effective adjuvant in tumor immunotherapy via enhanced capacity of DC activation and Ag presentation.