Interleukin-13 receptor α2 DNA prime boost vaccine induces tumor immunity in murine tumor models

Background  

DNA vaccines represent an attractive approach for cancer treatment by inducing active T cell and B cell immune responses to tumor antigens. Previous studies have shown that interleukin-13 receptor α2 chain (IL-13Rα2), a tumor-associated antigen is a promising target for cancer immunotherapy as high levels of IL-13Rα2 are expressed on a variety of human tumors. To enhance the effectiveness of DNA vaccine, we used extracellular domain of IL-13Rα2 (ECDα2) as a protein-boost against murine tumor models.     

Unique IL-13Rα2-based HIV-1 vaccine strategy to enhance mucosal immunity,CD8+ T-cell avidity and protective immunity

We have established that mucosal immunization can generate high-avidity human immunodeficiency virus (HIV)-specific CD8⁺ T cells compared with systemic immunization, and interleukin (IL)-13 is detrimental to the functional avidity of these T cells. We have now constructed two unique recombinant HIV-1 vaccines that co-express soluble or membrane-bound forms of the IL-13 receptor α2 (IL-13Rα2), which can “transiently” block IL-13 activity at the vaccination site causing wild-type animals to behave similar to an IL-13 KO animal. Following intranasal/intramuscular prime-boost immunization, these IL-13Rα2-adjuvanted vaccines have shown to induce (i) enhanced HIV-specific CD8⁺ T cells with higher functional avidity, with broader cytokine/chemokine profiles and greater protective immunity using a surrogate mucosal HIV-1 challenge, and also (ii) excellent multifunctional mucosal CD8⁺ T-cell responses, in the lung, genito-rectal nodes (GN), and Peyer's patch (PP). Data revealed that intranasal delivery of these IL-13Rα2-adjuvanted HIV vaccines recruited large numbers of unique antigen-presenting cell subsets to the lung mucosae, ultimately promoting the induction of high-avidity CD8⁺ T cells. We believe our novel IL-13R cytokine trap vaccine strategy offers great promise for not only HIV-1, but also as a platform technology against range of chronic infections that require strong sustained high-avidity mucosal/systemic immunity for protection.     

IL-1β as mucosal vaccine adjuvant: the specific induction of tissue-resident memory T cells improves the heterosubtypic immunity against influenza A viruses

A universal influenza vaccine must provide protection against antigenically divergent influenza viruses either through broadly neutralizing antibodies or cross-reactive T cells. Here, intranasal immunizations with recombinant adenoviral vectors (rAd) encoding hemagglutinin (HA) and nucleoprotein (NP) in combination with rAd-Interleukin-(IL)-1β or rAd-IL-18 were evaluated for their efficacy in BALB/c mice. Mucosal delivery of rAd-IL-1β enhanced HA-specific antibody responses including strain-specific neutralizing antibodies. Nevertheless, the beneficial effects on the local T cell responses were much more impressive reflected by increased numbers of CD103⁺CD69⁺ tissue-resident memory T cells (T_RM). This increased immunogenicity translated into superior protection against infections with homologous and heterologous strains including H1N1, pH1N1, H3N2, and H7N7. Inhibition of the egress of circulating T cells out of the lymph nodes during the heterologous infection had no impact on the degree of protection underscoring the unique potential of T_RM for the local containment of mucosal infections. The local co-expression of IL-1β and antigen lead to the activation of critical checkpoints in the formation of T_RM including activation of epithelial cells, expression of chemokines and adhesion molecules, recruitment of lung-derived CD103⁺ DCs, and finally local T_RM imprinting. Given the importance of T_RM-mediated protection at mucosal barriers, this study has major implications for vaccine development.     

Living high–training low altitude training: effects on mucosal immunity

Secretory immunoglobulin A (sIgA) is the major immunoglobulin of the mucosal immune system. Whereas the suppressive effect of heavy training on mucosal immunity is well documented, little is known regarding the influence of hypoxia exposure on sIgA during altitude training. This investigation examined the impact of an 18-day Living high–training low (LHTL) training camp on sIgA levels in 11 (six females and five males) elite cross-country skiers. Subjects from the control group (n=5) trained and lived at 1,200 m of altitude, whereas, subjects from the LHTL group (n=6) trained at 1,200 m, but lived at a simulated altitude of 2,500, 3,000 and 3,500 m (3×6-day, 11 h day^–1) in hypoxic rooms. Saliva samples were collected before, after each 6-day phases and 2 weeks thereafter (POST). Salivary sIgA, protein and cortisol were measured. There was a downward trend in sIgA concentrations over the study, which reached significance in LHTL (P<0.01), but not in control (P=0.08). Salivary IgA concentrations were still lower baseline at POST (P<0.05). Protein concentration increased in LHTL (P<0.05) and was negatively correlated with sIgA concentration after the 3,000 and 3,500 m-phase and at POST (P<0.05 all). Cortisol concentrations were unchanged over the study and no relationship was found between cortisol and sIgA. In summary, data were strongly suggestive of a cumulative negative effect of physical exercise and hypoxia on sIgA levels during LHTL training. Two weeks of active recovery did not allow for proper sIgA recovery. The mechanism underlying this depression of sIgA could be mediated by neural factors.     

The “vaccine” hubbub: Viral load comparisons of SARS-CoV-2 Delta and Omicron variants against different vaccine–booster vaccine combinations

There is a significant body of evidence showing that efficient vaccination schemes against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is helping control the coronavirus disease 2019 (COVID-19) pandemic. However, this goal cannot be achieved without real world data highlighting the impact of vaccines against viral spread. In this study, we have aimed at differentially investigating the impact of COVID-19 vaccines (CoronaVac, Pfizer/BioNTech, Astra/Zeneca Oxford, Janssen) used in North Cyprus in limiting the viral load of Delta and Omicron variants of SARS-COV-2. We have utilized real-time quantitative polymerase chain reaction cycle threshold values (Ct values) as a proxy of viral load of the two SARS-CoV-2 variants. Our results indicate that the administration of at least two doses of the messenger RNA-based Pfizer/BioNTech vaccine leads to the lowest viral load (highest Ct values) obtained for both Omicron and Delta variants. Interestingly, regardless of the vaccine type used, our study revealed that Delta variant produced significantly higher viral loads (lower Ct values) compared with the Omicron variant, where the latter was more commonly associated with younger patients. Viral spread is a crucial factor that can help determine the future of the pandemic. Thus, prioritizing vaccines that will play a role in not only preventing severe disease but also in limiting viral load and spread may contribute to infection control strategies.     

Hepatocyte growth factor mediates mesenchymal stem cell–induced recovery in multiple sclerosis models

Mesenchymal stem cells (MSCs) have emerged as a potential therapy for a range of neural insults. In animal models of multiple sclerosis, an autoimmune disease that targets oligodendrocytes and myelin, treatment with human MSCs results in functional improvement that reflects both modulation of the immune response and myelin repair. Here we demonstrate that conditioned medium from human MSCs (MSC-CM) reduces functional deficits in mouse MOG35–55-induced experimental autoimmune encephalomyelitis (EAE) and promotes the development of oligodendrocytes and neurons. Functional assays identified hepatocyte growth factor (HGF) and its primary receptor cMet as critical in MSC-stimulated recovery in EAE, neural cell development and remyelination. Active MSC-CM contained HGF, and exogenously supplied HGF promoted recovery in EAE, whereas cMet and antibodies to HGF blocked the functional recovery mediated by HGF and MSC-CM. Systemic treatment with HGF markedly accelerated remyelination in lysolecithin-induced rat dorsal spinal cord lesions and in slice cultures. Together these data strongly implicate HGF in mediating MSC-stimulated functional recovery in animal models of multiple sclerosis.     

Co-immunization of plasmid DNA encoding IL-12 and IL-18 with Bacillus Calmette-Guérin vaccine against progressive tuberculosis

Purpose

Bacillus Calmette-Guérin (BCG) vaccine has widely been used to immunize against tuberculosis, but its protective efficacy is variable in adult pulmonary tuberculosis, while it is not efficiently protective against progressive infection of virulent Mycobacterium tuberculosis strains. In this study, the protective effects of plasmid DNA vaccine constructs encoding IL-12 or IL-18 with the BCG vaccine were evaluated against progressive infection of M. tuberculosis, using mouse aerosol challenge model.

Materials and Methods

Plasmid DNA vaccine constructs encoding IL-12 or IL-18 were constructed and mice were immunized with the BCG vaccine or with IL-12 DNA or IL-18 DNA vaccine constructs together with the BCG vaccine.

Results

The BCG vaccine induced high level of interferon gamma (IFN-γ) but co-immunization of IL-12 or IL-18 DNA vaccine constructs with the BCG vaccine induced significantly higher level of IFN-γ than a single BCG vaccine. The BCG vaccine was highly protective at early stage of M. tuberculosis infection, but its protective efficacy was reduced at later stage of infection. The co-immunization of IL-12 DNA vaccine constructs with the BCG vaccine was slightly more protective at early stage of infection and was significantly more protective at later stage infection than a single BCG vaccine.

Conclusion

Co-immunization of IL-12 DNA vaccine with the BCG vaccine induced more protective immunity and was more effective for protection against progressive infection of M. tuberculosis.     

The Interleukin-1β/CXCL1/2/Neutrophil Axis Mediates Host Protection against Group B Streptococcal Infection

Previous studies have indicated that group B streptococcus (GBS), a frequent human pathogen, potently induces the release of interleukin-1β (IL-1β), an important mediator of inflammatory responses. Since little is known about the role of this cytokine in GBS disease, we analyzed the outcome of infection in IL-1β-deficient mice. These animals were markedly sensitive to GBS infection, with most of them dying under challenge conditions that caused no deaths in wild-type control mice. Lethality was due to the inability of the IL-1β-deficient mice to control local GBS replication and dissemination to target organs, such as the brain and the kidneys. Moreover, in a model of inflammation induced by the intraperitoneal injection of killed GBS, a lack of IL-1β was associated with selective impairment in the production of the neutrophil chemokines CXCL1 and CXCL2 and in neutrophil recruitment to the peritoneal cavity. Decreased blood neutrophil counts and impaired neutrophil recruitment to the brain and kidneys were also observed during GBS infection in IL-1β-deficient mice concomitantly with a reduction in CXCL1 and CXCL2 tissue levels. Notably, the hypersusceptibility to GBS infection observed in the immune-deficient animals was recapitulated by neutrophil depletion with anti-Gr1 antibodies. Collectively, our data identify a cytokine circuit that involves IL-1β-induced production of CXCL1 and CXCL2 and leads the recruitment of neutrophils to GBS infection sites. Moreover, our data point to an essential role of these cells in controlling the progression and outcome of GBS disease.     

Putative roles of a proline–glutamic acid-rich protein (PE3) in intracellular survival and as a candidate for subunit vaccine against Mycobacterium tuberculosis

The proline–glutamic acid (PE) protein family of Mycobacterium tuberculosis (Mtb) plays diverse roles in the pathogenesis and modulation of host immune responses. The uniqueness of conserved regions of PE proteins may be useful to test and validate their corresponding functions. Hence, the present study has been undertaken to demonstrate the role of PE3 (Rv0159c) for persistence, host immune response and immunoprophylaxis. We have expressed Mtb-specific PE3 gene in M. smegmatis (MS) and used the strain to infect J774A.1 macrophage cells and BALB/c mice. It was observed that during the infection, the MS expressing PE3 showed higher bacterial load when compared to infection with wild-type MS. In hypoxic condition, the expression level of PE3 gene was induced in Mtb, which further showed its relevance in the cell survival during hypoxia-induced persistence. The expression level of PE3 in Mtb was markedly induced during chronic stage of murine infection, which reiterated its importance in mycobacterial persistence in the host. The immunization of mice with recombinant PE3 protein stimulated the secretion of TNF, IL-6 and IL-2 cytokines and generated strong protective immunity against challenge with live mycobacteria, which was evidenced by decreased viable bacilli in the lungs, histopathological changes and increased survival of PE3 immunized mice. Conclusively, the results indicated that PE3 plays significant roles in mycobacterial persistence during infection, modulate host immune response and hence could be a prospective candidate for the development of subunit vaccine against tuberculosis.     

Oral recombinant Mycobacterium bovis bacillus Calmette-Guérin expressing HIV-1 antigens as a freeze-dried vaccine induces long-term,HIV-specific mucosal and systemic immunity

Induction of HIV-1-specific immune responses was evaluated using a recombinant BCG (rBCG) vector-based vaccine expressing HIV-1 Env V3 peptide (rBCG-pSOV3J1). rBCG-pSOV3J1 was manufactured as a freeze-dried preparation based on good laboratory practice guidelines. Guinea pigs were immunized with the freeze-dried rBCG vaccine by oral administration to test the effectiveness of what is generally considered the most convenient and practical route for vaccination. While delayed-type hypersensitivity (DTH) skin reactions to purified protein derivative were not detected in any of the animals receiving oral rBCG-pSOV3J1, HIV-1 V3J1 antigen-specific DTH responses were detected in all of the immunized guinea pigs 1.5 years after immunization. In addition, significant proliferative responses against HIV-1 V3J1 antigen were measured in peripheral blood mononuclear cells and splenocytes from all animals receiving oral rBCG. Interestingly, intestinal intraepithelial lymphocytes from the animals also exhibited high levels of proliferative activity against HIV-1 V3J1 antigen. These results suggest that oral vaccination of guinea pigs with freeze-dried rBCG-pSOV3J1 induces high levels of functional T cells specific for HIV-1 antigens in both mucosal and systemic compartments and suggest that this approach has potential for use as a vaccine against HIV-1.     

NLRP12 modulates host defense through IL-17A–CXCL1 axis

We used an extracellular pathogen Klebsiella pneumoniae to determine the role of NLRP12 (NOD-like receptor (NLR) family pyrin domain containing 12) as this bacterium is associated with devastating pulmonary infections. We found that human myeloid cells (neutrophils and macrophages) and non-myeloid cells (epithelial cells) show upregulation of NLRP12 in human pneumonic lungs. NLRP12-silenced human macrophages and murine Nlrp12^−/− macrophages displayed reduced activation of nuclear factor-κB and mitogen-activated protein kinase, as well as expression of histone deacetylases following K. pneumoniae infection. NLRP12 is important for the production of interleukin-1β (IL-1β) in human and murine macrophages following K. pneumoniae infection. Furthermore, host survival, bacterial clearance, and neutrophil recruitment are dependent on NLRP12 following K. pneumoniae infection. Using bone marrow chimeras, we showed that hematopoietic cell-driven NLRP12 signaling predominantly contributes to host defense against K. pneumoniae. Intratracheal administration of either IL-17A+ CD4 T cells or chemokine (C–X–C motif) ligand 1 (CXCL1+) macrophages rescues host survival, bacterial clearance, and neutrophil recruitment in Nlrp12^−/− mice following K. pneumoniae infection. These novel findings reveal the critical role of NLRP12–IL-17A–CXCL1 axis in host defense by modulating neutrophil recruitment against this extracellular pathogen.     

Reconstitution of Interleukin-17–Producing T Helper Cells after Allogeneic Hematopoietic Cell Transplantation

Interleukin 17A (IL-17)-producing CD4⁺ T helper type 17 (Th17) cells have recently drawn attention as possible effector cells of acute graft-versus-host disease (GVHD) after allogeneic hematopoietic cell transplantation (HCT) in murine models. Their role after allogeneic HCT in humans is unknown. In this prospective study, Th17, Th1/17, and Th1 cells were quantified in the peripheral blood of 80 patients within the first 3 months after allogeneic HCT using intracellular cytokine staining and flow cytometry. Within the observation period, Th1, Th1/17, and Th17 cells did not reconstitute to levels of healthy control subjects. In contrast to Th1 cells, no further expansion of Th1/17 and Th17 cells was observed during the first month after HCT. Antithymocyte globulin during conditioning significantly reduced the frequency of Th1/17 and Th17 cells but not of Th1 cells. Acute GVHD was not associated with significant changes in the size of the Th1, Th1/17, or Th17 cell subsets. Cytomegalovirus reactivation triggered the expansion of all T helper subsets, and Th1 cells showed the strongest increase. In contrast, no significant changes were found in the T helper cell compartment of patients with bacterial infections compared with time-matched control subjects. In conclusion, quantitative reconstitution of Th1, Th1/17, and Th17 cells is impaired within the first 3 months after HCT, especially when antithymocyte globulin is administered during conditioning. Cytomegalovirus reactivation, but not acute GVHD or bacterial infection, triggered the absolute expansion of these T cell subsets.     

Nerve growth factor protects retinal ganglion cells against injury induced by retinal ischemia–reperfusion in rats

Abstract

In this study, we investigated the protective effect of mouse nerve growth factor (NGF) on retinal ganglion cell (RGC) injury induced by retinal ischemia–reperfusion (RIR) in rats and explored its possible mechanisms of action. RIR caused a significant injury to RGCs and an obvious impairment of the inner retina functions, which could be seen from flash electroretinogram and flash visual evoked potential recordings. RIR also increased the expression of the apoptotic protein Bax while decreasing the expression of Bcl-2 and the phosphorylation of protein kinase B (Akt) in RGCs. Preinjection (i.m.) of NGF for 22 d reversed the injury induced by RIR and ameliorated the inner retina functions. NGF also reduced the expression of Bax and reversed the reduction of Bcl-2 and the phosphorylated Akt induced by RIR. These results indicate that NGF produces a neuroprotective effect on RGCs against RIR injury and the protective effect of NGF is mainly mediated by the PI-3K/Akt signaling pathway.     

Assessment of BIV1-CovIran inactivated vaccine–elicited neutralizing antibody against the emerging SARS-CoV-2 variants of concern

ObjectivesThe BIV1-CovIran vaccine is highly effective against COVID-19. The neutralizing potency of all SARS-CoV-2 vaccines seems to be decreased against variants of concern. We assessed the sensitivity of the Alpha (B.1.1.7), Beta (B.1.351), and Delta (B.1.617.2) variants to neutralizing antibodies (NAbs) present in sera from individuals who had received the BIV1-CovIran candidate vaccine compared with an original Wuhan-related strain.MethodsThe ability of vaccine serum to neutralize the variants was measured using the conventional virus neutralization test. The correlation of spike (S) protein antibody and anti-receptor binding domain with neutralizing activity was investigated.ResultsThe current study demonstrated that 29 of 32 (90.6%; 95% CI: 75.0–98.0) of the vaccinees developed NAbs against a Wuhan-related strain. It is noteworthy that 28 (87.50%) and 24 of 32 (75%) of the recipients were able to produce NAbs against Alpha, Beta, and Delta variants, respectively. Serum virus-neutralizing titres for different SARS-CoV-2 strains were weakly correlated with anti–receptor binding domain antibodies (Spearman r = 36-42, p < 0.05), but not S-binding antibodies (p > 0.05).DiscussionAlthough there was a reduction in neutralization titres against the Alpha, Beta, and Delta variants compared with the Wuhan strain, BIV1-CovIran still exhibited potent neutralizing activity against the SARS-CoV-2 variants of concern.