Mycobacterium tuberculosis variant bovis (MBO) has one of the widest known mammalian host ranges, including humans. Despite characterization of this pathogen in the 1800s, and whole genome sequencing of a UK strain (AF2122) nearly two decades ago, the basis of its host specificity and pathogenicity remains poorly understood. Recent experimental calf infection studies show that MBO strain Ravenel (MBO Ravenel) is attenuated in the cattle host. In the present study, experimental infections were performed to define attenuation and whole genome sequencing completed to identify regions of differences (RD) and single nucleotide polymorphisms (SNPs) to explain the observed attenuation. Comparative genomic analysis of MBO Ravenel against three pathogenic strains of MBO (strains AF2122-97, 10-7428 and 95-1315) was performed. Experimental infection studies on 5 calves each, with either MBO Ravenel or 95-1315, revealed no visible lesions in all 5 animals in the Ravenel group despite robust IFN-γ responses. Out of 486 polymorphisms in the present analysis, 173 were unique to MBO Ravenel among the strains compared. A high-confidence subset of 9 unique SNPs were missense mutations in genes with annotated functions impacting 2 major MBO survival and virulence pathways: 1) Cell wall synthesis & transport [espH (A103T), mmpL8 (V888I), aftB (H484Y), eccC5 (T507M), rpfB (E263G)], and 2) Lipid metabolism & respiration [mycP1(T125I), pks5 (G455S), fadD29 (N231S), fadE29 (V360G)]. These substitutions likely contribute to the observed attenuation. Results from experimental calf infections and the functional attributions of polymorphic loci on the genome of MBO Ravenel provide new insights into the strain’s genotype-disease phenotype associations.

The coronavirus disease 2019 (COVID-19) is now a global pandemic caused by the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Unlike other known coronaviruses, such as the Middle East respiratory syndrome coronavirus (MERS-CoV), SARS-CoV-2 reveals new clinical, immunological, and pathologic features. The lymphocyte depletion, macrophage and neutrophil hyperactivation, cytokine dysregulation, thrombophilia, delayed antiviral response, and immune exhaustion are key immunological findings linked to the clinical progression of this disease. Understanding and identifying the underlying immunological basis of COVID-19 is crucial to designing effective therapies. Here, we provide an overview of immunopathogenesis driven by SARS-CoV-2 after its interactions with the immune system.

Mosquito-borne viral disease dengue is a global public health problem causing a wide spectrum of clinical manifestations ranging from mild dengue fever to severe dengue with plasma leakage and bleeding which are often associated to fatality. To date, there are no specific medications to treat dengue and prevent the risk of hemorrhage. Dengue is caused by one of the four related antigenically distinct serotypes, DENV-1 to DENV-4. The growing burden that represents the four DENV serotypes has intensified both basic and applied researches to better understand the dengue physiopathology. It has been proposed a significant role for the secreted soluble DENV nonstructural protein 1 (sNS1) glycoprotein in the pathogenesis of severe dengue. Here, we provided an overview on current knowledge about the role of sNS1 in the immunopathogenesis of dengue disease. The reasons for the consideration of sNS1 in the design of future dengue vaccine candidates will be discussed.