SummaryThe magnitude of the cellular adaptive immune response is critical for the control of Mycobacterium tuberculosis infection in the chronic phase. In addition, the genetic background is equally important for resistance or susceptibility to tuberculosis. In this study, we addressed whether lung populations of dendritic cells, obtained from genetically different hosts, would play a role in the magnitude and function of CD4 + populations generated after M. tuberculosis infection. directly associated with the host genetic background. Therefore, differences in the genetic background contribute to the identification of immunological biomarkers that can be used to design human assays to predict progression of M. tuberculosis infection.

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The protective effects of mycobacterial infections on lung allergy are well documented. However, the inverse relationship between tuberculosis and type 2 immunity is still elusive. Although type 1 immunity is essential to protection against Mycobacterium tuberculosis it might be also detrimental to the host due to the induction of extensive tissue damage. Here, we determined whether lung type 2 immunity induced by allergen sensitization and challenge could affect the outcome of M. tuberculosis infection. We used two different protocols in which sensitization and allergen challenge were performed before or after M. tuberculosis infection. We found an increased resistance to M. tuberculosis only when allergen exposure was given after, but not before infection. Infected mice exposed to allergen exhibited lower bacterial load and cellular infiltrates in the lungs. Enhanced resistance to infection after allergen challenge was associated with increased gene expression of alternatively activated macrophages (M2 macrophages) and IL-33 levels. Accordingly, either adoptive transfer of M2 macrophages or systemic IL-33 treatment was effective in attenuating M. tuberculosis infection. Notably, the enhanced resistance induced by allergen exposure was dependent on IL-33 receptor ST2. Our work indicates that IL-33 might be an alternative therapeutic treatment for severe tuberculosis.

Our findings show that the Hsp65/CpG treatment is a promising strategy for consideration in translational studies.

In Brazil, the species Tityus serrulatus is responsible for the most severe cases of scorpion envenomation. There is currently a need for new scorpion anti-venoms that are more effective and less harmful. This study attempted to produce human monoclonal antibodies capable of inhibiting the activity of T. serrulatus venom (TsV), using the Griffin.1 library of human single-chain fragment-variable (scFv) phage antibodies. Four rounds of phage antibody selection were performed, and the round with the highest phage antibody titer was chosen for the production of monoclonal phage antibodies and for further analysis. The scFv 2A, designated serrumab, was selected for the production and purification of soluble antibody fragments. In a murine peritoneal macrophage cell line (J774.1), in vitro assays of the cytokines interleukin (IL)-6, tumor necrosis factor (TNF)-α, and IL-10 were performed. In male BALB/c mice, in vivo assays of plasma urea, creatinine, aspartate transaminase, and glucose were performed, as well as of neutrophil recruitment and leukocyte counts. It was found that serrumab inhibited the TsV-induced increases in the production of IL-6, TNFα, and IL-10 in J774.1 cells. The in vivo inhibition assay showed that serrumab also prevented TsV-induced increases in the plasma levels of urea, creatinine, aspartate transaminase, and glucose, as well as preventing the TsV-induced increase in neutrophil recruitment. The results indicate that the human monoclonal antibody serrumab is a candidate for inclusion in a mixture of specific antibodies to the various toxins present in TsV. Therefore, serrumab shows promise for use in the production of new anti-venom.

Adeno associated viral (AAV) vectors have emerged as a preferred platform for in vivo gene replacement therapy and represent one of the most promising strategies to treat monogenetic disorders such as hemophilia. However, immune responses to gene transfer have hampered human gene therapy in clinical trials. Over the past decade, it has become clear that innate immune recognition provides signals for the induction of antigen-specific responses against vector or transgene product. In particular, TLR9 recognition of the vector’s DNA genome in plasmacytoid dendritic cells (pDCs) has been identified as a key factor. Data from clinical trials and pre-clinical studies implement CpG motifs in the vector genome as drivers of immune responses, especially of CD8+ T cell activation. Here, we demonstrate that cross-priming of AAV capsid-specific CD8+ T cells depends on XCR1+ dendritic cells (which are likely the main cross-presenting cell that cooperates with pDCs to activate CD8+ T cells) and can be minimized by the elimination of CpG motifs in the vector genome. Further, a CpG-depleted vector expressing human coagulation factor IX showed markedly reduced (albeit not entirely eliminated) CD8+ T cell infiltration upon intramuscular gene transfer in hemophilia B mice when compared to conventional CpG+ vector (comprised of native sequences), resulting in better preservation of transduced muscle fibers. Therefore, this deimmunization strategy is helpful in reducing the potential for CD8+ T cell responses to capsid or transgene product. However, CpG depletion had minimal effects on antibody responses against capsid or transgene product, which appear to be largely independent of CpG motifs.

SummaryThe voltage-gated potassium channel Kv1.3 is a novel target for immunomodulation of autoreactive effector memory T cells, which play a major role in the pathogenesis of autoimmune diseases. In this study, the Ts6 and Ts15 toxins isolated from Tityus serrulatus (Ts) were investigated for their immunosuppressant roles on CD4 + cell subsets: naive, effector (T EF ), central memory (T CM ) and effector memory (T EM ). The electrophysiological assays confirmed that both toxins were able to block Kv1.3 channels. Interestingly, an extended Kv channel screening shows that Ts15 blocks Kv2.1 channels. Ts6 and Ts15 significantly inhibit the proliferation of T EM cells and interferon-c production; however, Ts15 also inhibits other CD4 + cell subsets (naive, T EF and T CM ). Based on the Ts15 inhibitory effect of proliferation of all CD4 + cell subsets, and based on its blocking effect on Kv2.1, we investigated the Kv2.1 expression in T cells. The assays showed that CD4 + and CD8 + cells express the Kv2.1 channels mainly extracellularly with T CM cells expressing the highest number of Kv2.1 channels. We also provide in vivo experimental evidence to the protective effect of Ts6 and Ts15 on delayed-type hypersensitivity reaction. Altogether, this study presents the immunosuppressive behaviour of Ts6 and Ts15 toxins, indicating that these toxins could be promising candidates for autoimmune disease therapy. Moreover, this is the first report illustrating the involvement of a novel K + channel subtype, Kv2.1, and its distribution in T-cell subsets.