A Dendritic Cell-Activating Rv1876 Protein Elicits Mycobacterium Bovis BCG-Prime Effect via Th1-Immune Response

The widely administered tuberculosis (TB) vaccine, Bacillus Calmette-Guerin (BCG), is the only licensed vaccine, but has highly variable efficiency against childhood and pulmonary TB. Therefore, the BCG prime-boost strategy is a rational solution for the development of new TB vaccines. Studies have shown that Mycobacterium tuberculosis (Mtb) culture filtrates contain proteins that have promising vaccine potential. In this study, Rv1876 bacterioferritin was identified from the culture filtrate fraction with strong immunoreactivity. Its immunobiological potential has not been reported previously. We found that recombinant Rv1876 protein induced dendritic cells’ (DCs) maturation by MAPK and NF-κB signaling activation, induced a T helper type 1 cell-immune response, and expanded the population of the effector/memory T cell. Boosting BCG with Rv1876 protein enhanced the BCG-primed Th1 immune response and reduced the bacterial load in the lung compared to those of BCG alone. Thus, Rv1876 is a good target for the prime-boost strategy.

Recurrence of Graves’ Disease (a Th1-type Cytokine Disease) Following SARS-CoV-2 mRNA Vaccine Administration: A Simple Coincidence?

Graves’ disease is the most frequent cause of hyperthyroidism in young women. This auto-immune disease is due to the production of class 1 IgG stimulating the TSH receptor. These antibodies are produced secondary to a Th1 immune response in which interferon gamma plays a key role. Vaccination is ongoing worldwide against SARS-CoV-2 and some of the vaccines include mRNA which seems to stimulate the Th1 immune response. Here, we report a case of recurrence of hyperthyroidism due to Graves’ disease following mRNA vaccination and discuss the possible implicated mechanism. This observation argues for a systematic study of a population of patients with previous Graves’ disease in order to assess the risk of recurrence following vaccination.

Leishmaniasis: A new method for confirming cure and detecting asymptomatic infection in patients receiving immunosuppressive treatment for autoimmune disease

Visceral leishmaniasis (VL) in patients receiving immunosuppressant drugs for autoimmune disease has been on the rise. It is important—but difficult—to know when cure has been achieved in these patients since the withdrawal of immunosuppressants during antileishmania treatment is commonly required, and there is a risk of relapse when immunosuppression is restored. The prevalence of asymptomatic infection among those immunosuppressed for autoimmune disease is also uncertain. The present work describes how cytokine release assays can be used to confirm the cure of VL, and to determine the prevalence of asymptomatic infection, in such patients. After collection of blood from volunteers (n = 108), SLA-stimulation of peripheral blood mononuclear cell cultures and of whole blood was found to induce the production of different combinations of cytokines that served to confirm recovery from VL, and asymptomatic Leishmania infection. Indeed, cure was confirmed in 14 patients, all of whom showed a specific Th1 immune response against Leishmania, and the prevalence of asymptomatic infection was determined as 21.27%. Cytokine profiles could be used to manage VL in patients with autoimmune disease, and to identify and better protect those with asymptomatic infection who are at risk of developing this disease.

The Pivotal Role of Signal Regulatory Protein α in Exacerbating Pulmonary Fibrosis Complicated with Bacterial Infection

The pathogenesis of pulmonary fibrosis remains unknown. However, bacterial infections in patients with idiopathic pulmonary fibrosis are a serious complication that exacerbate the disease. Serum levels of Surfactant Protein D (SPD) are known to be elevated in patients with pulmonary fibrosis, but the role of SPD in pulmonary fibrosis complicated with bacterial infection is unknown. Lipopolysaccharide upregulates Interleukin (IL)-12p40 expression and IL-12p40 promotes Interferon Gamma (IFNγ) production to induce the T helper cell 1 (Th1) immune response via Signal Transducers and Activators of Transcription 4 (STAT4) signaling. A lack of IFNγ shifts the immune response from Th1 to Th2. IL-4 is a profibrotic Th2 cytokine that activates fibroblasts. Granulocyte-macrophage colony-stimulating factor induced by IL-1 and TNFα during the Th1 immune response upregulates Signal Regulatory Protein α (SIRPα) expression. Interferon Regulatory Factor 1 (IRF1) functions as the promoter activator of IL-12p40 after stimulation with LPS. SPD is a ligand for SIRPα, and SPD/SIRPα ligation activates the Mitogen-Activated Protein Kinase (MAPK)/Extracellular Signal-Related Kinase (ERK) signal cascade; ERK downregulates Interferon Regulatory Factor 1 (IRF1) expression. Consequently, the SPD/SIRPα signaling pathway decreases IL-12p40 production in human macrophages after exposure to LPS. IL-12p40 is a key immunoregulatory factor in bacterial infection that promotes production of IFNγ by T lymphocytes. Pulmonary fibroblasts are activated by IL-4/IL-4R ligation. IFNγ induces IRF1 via STAT1 signaling, and IRF1 acts as the promoter repressor of IL-4 to attenuate its production. IFNγ also inhibits IL-4R expression. A reduction in IFNγ induced by IL-12p40 deficiency via the SPD/SIRPα signaling pathway enhances IL-4 and IL-4R expression to augment the activity of fibroblasts. This finding indicates that pulmonary fibrosis is exacerbated by SPD/SIRPα signaling during bacterial infection.

Claudin-Low Breast Cancer Inflammatory Signatures Support Polarization of M1-Like Macrophages with Protumoral Activity

We previously reported that triple-negative breast cancer (BRCA) cells overexpress the cytokines GM-CSF, G-CSF, MCP-1, and RANTES, and when monocytes were 3-D co-cultured with them, M1-like macrophages were generated with the ability to induce aggressive features in luminal BRCA cell lines. These include upregulation of mesenchymal and stemness markers and invasion. In this study, we stimulated peripheral blood monocytes with the four cytokines and confirmed their capacity to generate protumoral M1-like macrophages. Using the METABRIC BRCA database, we observed that GM-CSF, MCP-1, and RANTES are associated with triple-negative BRCA and reduced overall survival, particularly in patients under 55 years of age. We propose an extended M1-like macrophage proinflammatory signature connected with these three cytokines. We found that the extended M1-like macrophage signature coexists with monocyte/macrophage, Th1 immune response, and immunosuppressive signatures, and all are enriched in claudin-low BRCA samples, and correlate with reduced patient overall survival. Furthermore, we observed that all these signatures are also present in mesenchymal carcinomas of the colon (COAD) and bladder (BLCA). The claudin-low tumor subtype has an adverse clinical outcome and remains poorly understood. This study places M1 macrophages as potential protumoral drivers in already established cancers, and as potential contributors to claudin-low aggressiveness and poor prognosis.