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Brucellosis is a global zoonotic infection caused by Brucella bacteria, which poses a significant burden on society. While transmission prevention is currently the most effective method, the absence of a licenced vaccine for humans necessitates the urgent development of a safe and effective vaccine. Recombinant protein-based subunit vaccines are considered promising options, and in this study, the Brucella BP26 protein is expressed using prokaryotic expression systems. The immune responses are evaluated using the well-established adjuvant CpG-ODN. The results demonstrate that rBP26 supplemented with a CpG adjuvant induces M1 macrophage polarization and stimulates cellular immune responses mediated by Th1 cells and CD8+ T cells. Additionally, it generates high levels of rBP26-specific antibodies in immunized mice. Furthermore, rBP26 immunization activates, proliferates, and produces cytokines in T lymphocytes while also maintaining immune memory for an extended period of time. These findings shed light on the potential biological function of rBP26, which is crucial for understanding brucellosis pathogenesis. Moreover, rBP26 holds promise as an effective subunit vaccine candidate for use in endemic areas.

Alveolar echinococcosis (AE) is a zoonotic parasitic disease caused by infection with the larval stage of Echinococcus multilocularis and a major challenge to human public health. Vaccines are the most effective way to prevent and control infectious diseases. We previously revealed that the Echinocuccus granulosus recombinant protein P29 is a good vaccine candidate against E. granulosus. However, the protective and immunological mechanism of rEg.P29 against E. multilocularis remain unclear. In this study, CD4+ T cell-deficient mice are transferred with spleen CD4+ T cells isolated from wild-type mice and subjected to rEg.P29 immunization, and then these immunized mice are infected with E. multilocularis. The cyst inhibition rate is calculated by weighing the body and cyst weights. The level of antibody is detected by ELISA. Flow cytometry is used to detect the level of IFN-γ production by CD4+ T and CD8+ T cells. The cytokines in culture supernatant are detected by ELISA. The expressions of CD44 and CD62L on memory T cells are determined by flow cytometry. The results show the cyst inhibition rate is 41.52% after adoptive transfer of CD4+ T cells. Furthermore, the levels of IgG, IgM, IgA and IgE in serum are significantly increased compared with those in the PBS group. The IFN-γ-secretion by CD8+ T cells and the level of IFN-γ in culture supernatant are obviously increased; and the number of CD4+ T cells is increased, but the number of IFN-γ producing CD4+ T cells has no significant difference compared with PBS group. In addition, the number of CD44+CD62L‒CD8+ memory T cells in the spleen is significantly increased, while the number of CD44‒CD62L+ CD8+ memory T cells is not significantly altered. Collectively, rEg.P29 can alleviate E. multilocularis infection by inducing humoral immune responses and CD8+ T cell responses.

Alveolar echinococcosis (AE) is a highly lethal helminth infection. Current chemotherapeutic strategies for AE primarily involve the use of benzimidazoles (BZs) such as mebendazole (MDZ) and albendazole (ABZ), which exhibit limited efficacy. In a previous study, the vaccine of recombinant Echinococcus granulosus P29 (rEgP29) showed significant immunoprotection against E. granulosus in both mice and sheep. In the current study, we utilized hybridoma technology to generate five monoclonal antibodies (mAbs) against P29, among which 4G10F4 mAb exhibited the highest antigen-specific binding capacity. This mAb was selected for further investigation of anti-AE therapy, both in vivo and in vitro. In vitro, 4G10F4 inhibited a noteworthy inhibition of E. multilocularis protoscoleces and primary cells viability through complement-dependent cytotoxicity (CDC) mechanism. In vivo, two experiments were conducted. In the first experiment, mice were intraperitoneally injected with Em protoscoleces, and subsequently treated with 4G10F4 mAb (2.5/5/10 mg/kg) at 12 weeks postinfection once per week for 8 times via tail vein injection. Mice that were treated with 4G10F4 mAb only in dosage of 5mg/kg exhibited a significant lower mean parasite burden (0.89±0.97 g) compared to isotype mAb treated control mice (2.21±1.30 g). In the second experiment, mice were infected through hepatic portal vein and treated with 4G10F4 mAb (5mg/kg) at one week after surgery once per week for 8 times. The numbers of hepatic metacestode lesions of the 4G10F4 treatment group were significantly lower in comparison to the isotype control group. Pathological analysis revealed severe disruption of the inner structure of the metacestode in both experiments, particularly affecting the germinal and laminated layers, resulting in the transformation into infertile vesicles after treatment with 4G10F4. In addition, the safety of 4G10F4 for AE treatment was confirmed through assessment of mouse weight and evaluation of liver and kidney function. This study presents antigen-specific monoclonal antibody immunotherapy as a promising therapeutic approach against E. multilocularis induced AE. Author summary: Echinococcosis encompasses two significant zoonotic tapeworm diseases, cystic echinococcosis (CE) and alveolar echinococcosis (AE), caused by Echinococcus granulosus and Echinococcus multilocularis, respectively. AE is widely acknowledged as the most fatal helminth infection, with a mortality rate exceeding 90% within 10–15 years of diagnosis if left untreated or inadequately treated. Two benzimidazole carbamates, albendazole and mebendazole, are the only anti-infective drugs that are clinically efficient in interrupting the larval growth of Echinococcus spp. However, due to their toxicity and limited efficacy, there is a pressing need to explore novel therapeutic strategies for AE. In this study, a therapeutic antibody named 4G10F4 was produced against hydatid P29 using hybridoma technology. This candidate antibody significantly inhibited E. multilocularis both in vitro and in vivo, representing a potentially efficacious and safe antigen-specific monoclonal antibody immunotherapy for the treatment of AE. Additionally, it has been identified as a promising antibody drug and molecular target for the development of anti-AE therapy. [ABSTRACT FROM AUTHOR]

Aging is generally associated with declining somatosensory function, which seems at odds with the high prevalence of chronic pain in older people. This discrepancy is partly related to the high prevalence of degenerative diseases such as osteoarthritis in older people. However, whether aging alters pain processing in the primary somatosensory cortex (S1), and if so, whether it promotes pain chronification is largely unknown. Herein, we report that older mice displayed prolonged nociceptive behavior following nerve injury when compared with mature adult mice. The expression of peroxisome proliferator‐activated receptor‐gamma coactivator‐1α (PGC‐1α) in S1 was decreased in older mice, whereas PGC‐1α haploinsufficiency promoted prolonged nociceptive behavior after nerve injury. Both aging and PGC‐1α haploinsufficiency led to abnormal S1 neural dynamics, revealed by intravital two‐photon calcium imaging. Manipulating S1 neural dynamics affected nociceptive behavior after nerve injury: chemogenetic inhibition of S1 interneurons aggravated nociceptive behavior in naive mice; chemogenetic activation of S1 interneurons alleviated nociceptive behavior in older mice. More interestingly, adeno‐associated virus‐mediated expression of PGC‐1α in S1 interneurons ameliorated aging‐associated chronification of nociceptive behavior as well as aging‐related S1 neural dynamic changes. Taken together, our results showed that aging‐associated decrease of PGC‐1α promotes pain chronification, which might be harnessed to alleviate the burden of chronic pain in older individuals. [ABSTRACT FROM AUTHOR]