About a quarter of the world's population with latent tuberculosis infection (LTBI) are the main source of active tuberculosis. Bacillus Calmette Guerin (BCG) cannot effectively control LTBI individuals from developing diseases. Latency-related antigens can induce T lymphocytes of LTBI individuals to produce higher IFN-γ levels than tuberculosis patients and normal subjects. Herein, we firstly compared the effects of M. tuberculosis (MTB) ag85ab and 7 latent DNA vaccines on clearing latent MTB and preventing its activation in the mouse LTBI model.
A mouse LTBI model was established, and then immunized respectively with PBS, pVAX1 vector, Vaccae vaccine, ag85ab DNA and 7 kinds of latent DNAs (including rv1733c, rv2660c, rv1813c, rv2029c, rv2628, rv2659c and rv3407) for three times. The mice with LTBI were injected with hydroprednisone to activate the latent MTB. Then, the mice were sacrificed for the bacterial count, histopathological examination, and immunological evaluation.
Using chemotherapy made the MTB latent in the infected mice, and then using hormone treatment reactivated the latent MTB, indicating that the mouse LTBI model was successfully established. After the mouse LTBI model was immunized with the vaccines, the lung colony-forming units (CFUs) and lesion degree of mice in all vaccines group were significantly decreased than those in the PBS group and vector group (P<0.0001, P<0.05). These vaccines could induce antigen-specific cellular immune responses. The number of IFN-γ effector T cells spots secreted by spleen lymphocytes in the ag85ab DNA group was significantly increased than those in the control groups (P<0.05). In the splenocyte culture supernatant, IFN-γ and IL-2 levels in the ag85ab, rv2029c, and rv2659c DNA groups significantly increased (P<0.05), and IL-17A levels in ag85ab and rv2659c DNA groups also significantly increased (P<0.05). Compared with the PBS and vector groups, the proportion of CD4+CD25+FOXP3+ regulatory T cells in spleen lymphocytes of ag85ab, rv2660c, rv2029c, and rv3407 DNA groups were significantly reduced (P<0.05).
MTB ag85ab and 7 kinds of latent DNA vaccines showed immune preventive efficacies on a mouse model of LTBI, especially the rv2659c, and rv1733c DNA. Our findings will provide candidates for the development of new multi-stage vaccines against TB.
Copyright © 2023 Liang, Li, Yang, Xiao, Liang, Mi, Xue, Gong, Wang, Wang, Zhang, Shi, Peng, Chen, Zhao and Wu.

Tuberculosis (TB) is a major global public health problem. New treatment methods on TB are urgently demanded.
Ninety-six female BALB/c mice were challenged with 2×104 colony-forming units (CFUs) of MTB H37Rv through tail vein injection, then was treated with 10μg, 50μg, 100μg, and 200μg of Mycobacterium tuberculosis (MTB) ag85a/b chimeric DNA vaccine delivered by intramuscular injection (IM) and electroporation (EP), respectively. The immunotherapeutic effects were evaluated immunologically, bacteriologically, and pathologically.
Compared with the phosphate-buffered saline (PBS) group, the CD4+IFN-γ+ T cells% in whole blood from 200 µg DNA IM group and four DNA EP groups increased significantly (P<0.05), CD8+IFN-γ+ T cells% (in 200 μg DNA EP group), CD4+IL-4+ T cells% (50 μg DNA IM group) and CD8+IL-4+ T cells% (50 μg and 100 μg DNA IM group, 100 μg and 200 μg DNA EP group) increased significantly only in a few DNA groups (P< 0.05). The CD4+CD25+ Treg cells% decreased significantly in all DNA vaccine groups (P<0.01). Except for the 10 μg DNA IM group, the lung and spleen colony-forming units (CFUs) of the other seven DNA immunization groups decreased significantly (P<0.001, P<0.01), especially the 100 μg DNA IM group and 50 μg DNA EP group significantly reduced the pulmonary bacterial loads and lung lesions than the other DNA groups.
An MTB ag85a/b chimeric DNA vaccine could induce Th1-type cellular immune reactions. DNA immunization by EP could improve the immunogenicity of the low-dose DNA vaccine, reduce DNA dose, and produce good immunotherapeutic effects on the mouse TB model, to provide the basis for the future human clinical trial of MTB ag85a/b chimeric DNA vaccine.
Copyright © 2022 Liang, Cui, Xiao, Liu, Yang, Ling, Wang, Wang, Wang and Wu.

Immunometabolism determines the fate and function of regulatory T cells. The metabolic phenotype of regulatory T cells (Treg) is affected by various factors. The relationship between Treg metabolism and function of mice with sepsis is not clear. We used liquid chromatography and tandem mass spectrometry (LC-MS/MS) to analyze the metabolic profiles of freshly-isolated spleen Treg cells in mice with sepsis. It was found that in severe infection, activated Treg cells depend on glycolysis and fatty acid oxidation, and inhibition of metabolic pathways has a significant impact on the number and quality of Treg cells. Understanding the metabolic characteristics of Treg cells in the real environment in the body helps to grasp the function of Treg cells and even the overall immune status. Targeting the metabolic pathway of Treg may provide a new method for the treatment of sepsis.
This journal is © The Royal Society of Chemistry.

Uveitis is a potentially sight-threatening form of ocular inflammation that affects the uvea in the wall of the eye. Currently available treatments for uveitis have exhibited profound adverse side effects. However, KS23 is a novel 23-amino-acid anti-inflammatory peptide derived from adiponectin that may have the capability to function as a safe alternative to these existing treatment options. We, therefore, evaluated the preventive effect of KS23 in experimental autoimmune uveitis (EAU).
EAU was induced in mice via immunization with the peptide interphotoreceptor retinoid binding protein 161-180 (IRBP161-180). KS23 was then administered every 2 days via intraperitoneal injection to induce protection against EAU. Clinical and histopathological scores were employed to evaluate the disease progression. Inflammatory cytokines were also quantified using ELISA, and the expression levels of specific chemokines and chemokine receptors were assessed via qRT-PCR. In addition, the proportions of Th1 and Th17 cells were detected via flow cytometry, and the expression levels of specific proteins were quantified from the retina of mice using western blot analysis, to elucidate the specific mechanism of action employed by KS23 to suppress the inflammation associated with EAU.
KS23 was found to significantly improve EAU-associated histopathological scores, while decreasing the expression of pro-inflammatory cytokines (IFN-γ, TNF-α, IL-6, and IL-17A), chemokines (LARC, RANTES, MIG, IP-10), and chemokine receptors (CCR6 and CXCR3). The proportions of Th1 and Th17 cells were also suppressed following intraperitoneal injection with KS23. The anti-inflammatory mechanism employed by KS23 was determined to be associated with the activation of AMPK and subsequent inhibition of NF-κB.
KS23 decreased the proportions of Th1 and Th17 cells to effectively ameliorate the progression of EAU. It may, therefore, serve as a promising potential therapeutic agent for uveitis.

Leukotriene B4 receptor 1 (BLT1) triggers the migration of granulocytes and activated T cells; however, its role in B-cell function remains unclear. Here we report that BLT1 is required to induce the production of antigen-specific IgA against oral vaccine through mediating innate immune signals from commensal bacteria. B cells acquire BLT1 expression during their differentiation to IgA+ B cells and plasma cells in Peyer's patches and the small intestinal lamina propria, respectively. BLT1 KO mice exhibited impaired production of antigen-specific fecal IgA to oral vaccine despite normal IgG responses to systemically immunized antigen. Expression of MyD88 was decreased in BLT1 KO gut B cells and consequently led to diminished proliferation of commensal bacteria-dependent plasma cells. These results indicate that BLT1 enhances the proliferation of commensal bacteria-dependent IgA+ plasma cells through the induction of MyD88 and thereby plays a key role in the production of antigen-specific intestinal IgA.