China and the WHO pandemic treaty: a dive into stance, underpinnings, and implications.

The COVID-19 pandemic exposed gaps in global health governance, catalyzing proposals for a new WHO pandemic treaty. This paper investigates China's stance on the treaty, recognizing it as reflective of many developing countries' concerns, through a qualitative analysis of its interventions during the treaty's drafting and negotiations and an examination of historical and geopolitical factors. Findings reveal China's emphasis on respecting state sovereignty, differentiated obligations for developing nations, preventing stigma, and concrete capacity building-concerns shared across the Global South. Its posture balances pragmatism and principle, reflecting differentiated responsibilities as a major power and developing country along with philosophical divergences from Western legal thinking. While endorsing global cooperation, China insists on voluntary terms without impinging on policy space. Implications suggest that accommodating China's concerns about invasive compliance mechanisms and inequitable burdens through flexible provisions can shape the treaty's acceptance and architecture. Creative solutions reconciling sovereignty and collective action combined with concrete equity measures and depoliticized cooperation will determine the treaty's success. China's major role indicates its endorsement, representative of the Global South's voice, is essential for an impactful pandemic treaty and reformed global health governance.

Strategizing global health governance: unpacking opportunities and challenges for least developed nations within the WHO pandemic treaty framework.

Exploring the intricacies of the proposed WHO pandemic treaty, this paper underscores its potential benefits and challenges for Least Developed Nations (LDNs) in the global health landscape. While the treaty could elevate LDNs' access to vital resources, fortify health systems, and amplify their voice in global health governance, tangible challenges in safeguarding equitable access, protecting sovereignty, and ensuring compliance are illuminated. Concluding with targeted recommendations, the paper advocates for treaty revisions that assure resource access, safeguard LDNs' autonomy, and foster capacity-building. In essence, the paper emphasizes the imperative of genuinely empowering LDNs, crafting a pandemic treaty that establishes a more equitable, resilient, and inclusive global health future.

Roles of FcRn in Antigen-Presenting Cells during Autoimmunity and a Clinical Evaluation of Efgartigimod as an FcRn Blocker.

The immune system is a complex network of multiple cells, tissues, and organs that protects the body against foreign pathogenic invaders. However, the immune system may mistakenly attack healthy cells and tissues due to the cross-reactivity of anti-pathogen immunity, leading to autoimmunity by autoreactive T cells and/or autoantibody-secreting B cells. Autoantibodies can accumulate, resulting in tissue or organ damage. The neonatal crystallizable fragment receptor (FcRn) is an important factor in immune regulation through controlling the trafficking and recycling of immunoglobulin G (IgG) molecules, the most abundant antibody in humoral immunity. In addition to its role in IgG trafficking and recycling, FcRn is also involved in antigen presentation, which is a crucial step in the activation of the adaptive immune response via directing the internalization and trafficking of antigen-bound IgG immune complexes into compartments of degradation and presentation in antigen-presenting cells. Efgartigimod, an FcRn inhibitor, has shown promise in reducing the levels of autoantibodies and alleviating the autoimmune severity of myasthenia gravis, primary immune thrombocytopenia, and pemphigus vulgaris/foliaceus. This article aims to provide an overview of the importance of FcRn in antigen-presenting cells and its potential as a therapeutic target in autoimmune diseases, using efgartigimod as an example.

HIV associated cell death: Peptide-induced apoptosis restricts viral transmission.

The human immunodeficiency virus (HIV) is still a global pandemic and despite the successful use of anti-retroviral therapy, a well-established cure remains to be identified. Viral modulation of cell death has a significant role in HIV pathogenesis. Here we sought to understand the major mechanisms of HIV-induced death of lymphocytes and the effects on viral transmission. Flow cytometry analysis of lymphocytes from five latent HIV-infected patients, and HIV IIIB-infected MT2 cells demonstrated both necrosis and apoptosis to be the major mechanisms of cell death in CD4+ and CD4-/CD8- lymphocytes. Significantly, pro-apoptotic tumor necrosis factor (TNF) peptide (P13) was found to inhibit HIV-related cell death and reduced viral transmission. Whereas pro-necrotic TNF peptide (P16) had little effect on HIV-related cell death and viral transmission. Understanding mechanisms by which cell death can be manipulated may provide additional drug targets to reduce the loss of CD4+ cells and the formation of a viral reservoir in HIV infection.

In Vitro and In Vivo Antigen Presentation and Diagnosis Development of Recombinant Overlapping Peptides Corresponding to Mtb ESAT-6/CFP-10.

Cellular immunity in Mycobacteria tuberculosis (Mtb) infection is important for the pathogenesis and final clearance of intracellular Mtb infection. In addition, it is valuable for the diagnosis of tuberculosis. In this pioneering work, we tested in vitro and in vivo antigen presentation and diagnostic application of a recombinant overlapping peptide-protein derived from two Mtb RD1 antigens ESAT-6 and CFP-10 (ROP-TB). The overlapping peptide sequence of ROP-TB is cleaved by the cathepsin S enzyme and covers the entire length of the two proteins. ROP-TB can be expressed and purified from E. coli. Once taken in by antigen-presenting cells, ROP-TB can be cleaved into a peptide pool by cathepsin S within the cells. We found that in dendritic cells, ROP-TB can be processed in 6 hours of co-culture, while the ESAT-6/CFP-10 fusion protein remained in the endosomal compartment. In Mtb-infected mice, ROP-TB stimulated stronger specific T cell responses than pooled synthetic peptides derived from ESAT-6 and CFP-10. With regard to the presentation of in vivo antigens, in a guinea pig model infected with Mtb, ROP-TB induced delayed type hypersensitivity (DTH) responses comparable to those of the tuberculin purified protein derivative (PPD) and ESAT-6/CFP-10 fusion protein. In Mycobacterium bovis (Bovine TB)-infected cattle, ROP-TB elicited DTH responses. Finally, in Mtb infected patients, ROP-TB stimulated cellular immune responses in majority of patients (16/18) of different HLA phenotypes while a single peptide derived from the same proteins did not elicit the immune responses in all patients. In summary, in vitro and in vivo data suggest that ROP-TB stimulates a strong cellular immune response irrespective of HLA phenotypes and is therefore suitable for use in vitro and in vivo diagnostics.

Beyond Just Peptide Antigens: The Complex World of Peptide-Based Cancer Vaccines.

Peptide-based cancer vaccines rely upon the strong activation of the adaptive immune response to elicit its effector function. They have shown to be highly specific and safe, but have yet to prove themselves as an efficacious treatment for cancer in the clinic. This is for a variety of reasons, including tumour heterogeneity, self-tolerance, and immune suppression. Importance has been placed on the overall design of peptide-based cancer vaccines, which have evolved from simple peptide derivatives of a cancer antigen, to complex drugs; incorporating overlapping regions, conjugates, and delivery systems to target and stimulate different components of antigen presenting cells, and to bolster antigen cross-presentation. Peptide-based cancer vaccines are increasingly becoming more personalised to an individual's tumour antigen repertoire and are often combined with existing cancer treatments. This strategy ultimately aids in combating the shortcomings of a more generalised vaccine strategy and provides a comprehensive treatment, taking into consideration cancer cell variability and its ability to avoid immune interrogation.

Involvement of the VEGF signaling pathway in immunosuppression and hypoxia stress: analysis of mRNA expression in lymphocytes mediating panting in Jersey cattle under heat stress.

BACKGROUND: Extreme panting under heat stress threatens dairy cattle milk production. Previous research has revealed that the gas exchange-mediated respiratory drive in critically ill dairy cattle with low O2 saturation induces panting. Vascular endothelial growth factor (VEGF) signaling may play important roles in immunosuppression and oxidative stress during severe respiratory stress responses in heat-stressed cattle. The objectives of this study were to transcriptomically analyze mRNA expression mediating heat-induced respiratory stress-associated panting, evaluate gas exchange, screen hub genes, and verify the expression of proteins encoded by differentially expressed genes in lymphocyte pathways. RESULTS: Jersey cattle were naturally heat-exposed. Physiological data were collected for response evaluation, and blood was collected for gas exchange and gene expression assays at 06:00, 10:00 and 14:00 continuously for 1 week. Lymphocytes were isolated from whole-blood samples for mRNA-seq and expression analysis of key pathway genes/proteins. The cattle respiration rates differed with time, averaging 51 bpm at 06:00, 76 bpm at 10:00, and 121 bpm at 14:00 (p < 0.05). Gas exchange analysis showed that both pH and pCO2 differed with time: they were 7.41 and 41 mmHg at 06:00, 7.45 and 37.5 mmHg at 10:00, and 7.49 and 33 mmHg at 14:00, respectively (p < 0.01). Sixteen heat-related differentially expressed genes (DEGs; 13 upregulated and 3 downregulated) were screened between 212 DEGs and 1370 heat stress-affected genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) hub gene functional analysis annotated eleven genes to signal transduction, six genes to the immune response, and five genes to the endocrine response, including both prostaglandin-endoperoxide synthase 2 (PTGS2) and VEGF. Gene Ontology (GO) functional enrichment analysis revealed that oxygen regulation was associated with the phosphorus metabolic process, response to oxygen levels, response to decreased oxygen levels, response to hypoxia and cytokine activity terms. The main signaling pathways were the VEGF, hypoxia inducible factor-1(HIF-1), cytokine-cytokine receptor interaction and TNF pathways. Four genes involved Integrin beta 3 (ITBG3), PTGS2, VEGF, and myosin light chain 9 (MYL9) among the 16 genes related to immunosuppression, oxidative stress, and endocrine dysfunction were identified as participants in the VEGF signaling pathway and oxygenation. CONCLUSION: These findings help elucidate the underlying immune and oxygen regulation mechanisms associated with the VEGF signaling pathway in heat-stressed dairy cattle.

Survivin as a biological biomarker for diagnosis and therapy.

Introduction: Survivin (SVN) is a member of the inhibitor of apoptosis (IAP) protein family that promotes cellular proliferation and inhibits apoptosis. Overexpression of SVN is associated with autoimmune disease, hyperplasia, and tumors and can be used as a biomarker in these diseases. SVN is widely recognized as a tumor-associated antigen (TAA) and has become an important target for cancer diagnosis and treatment.Areas covered: We reviewed SVN research progress from the PubMed and clinical trials focused on SVN from https://clinicaltrials.gov since 2000 and anticipate future developments in the field. The trials reviewed cover various modalities including diagnostics for early detection and disease progression, small molecule inhibitors of the SVN pathway and immunotherapy targeting SVN epitopes.Expert opinion: The most promising developments involve anti-SVN immunotherapy, with several therapeutic SVN vaccines under evaluation in phase I/II trials. SVN is an important new immune-oncology target that expands the repertoire of individualized combination treatments for cancer.

HPV-16 E7-Specific Cellular Immune Response in Women With Cervical Intraepithelial Lesion Contributes to Viral Clearance: A Cross-Sectional and Longitudinal Clinical Study.

High-risk human papillomavirus (HPV) infection is the cause of almost all cervical cancers. HPV16 is one of the main risk subtypes. Although screening programs have greatly reduced the prevalence of cervical cancer in developed countries, current diagnostic tests cannot predict if mild lesions may progress into invasive lesions or not. In the current cross-sectional and longitudinal clinical study, we found that the HPV16 E7-specific T cell response in peripheral blood mononuclear cells of HPV16-infected patients is related to HPV16 clearance. It contributes to protecting the squamous interaepithelial lesion (SIL) from further malignant development. Of the HPV16 infected women enrolled (n = 131), 42 had neither intraepithelial lesion nor malignancy (NILM), 33 had low-grade SIL, 39 had high-grade SIL, and 17 had cervical cancer. Only one of 17 (5.9%) cancer patients had a positive HPV16 E7-specific T cell response, dramatically lower than the groups of precancer patients. After one year of follow-up, most women (28/33, 84.8%) with persistent HPV infection did not exhibit a HPV16 E7-specific T cell response. Furthermore, 3 malignantly progressed women, one progressed to high-grade SIL and two progressed to low-grade SIL, were negative to the HPV16 E7-specific T cell response. None of the patients with a positive HPV16 E7-specific T cell response progressed to further deterioration. Our observation suggests that HPV16 E7-specific T cell immunity is significant in viral clearance and contributes in protection against progression to malignancy.

Protective cellular immunity generated by cross-presenting recombinant overlapping peptide proteins.

Priming of naive CD8+ and CD4+ T cells by dendritic cells (DCs) requires effective antigen presentation on both MHC class I and II molecules. We have developed a novel technology to use recombinant overlapping peptides (ROP) that stimulate both CD8+ and CD4+ T cell immune responses. The single chain protein of a ROP is made up of overlapping peptides linked by the target sequence (LRMK) for cathepsin S, a protease found in the endosomes of DCs. We designed synthetic genes encoding ROPs derived from ovalbumin (OVA), tuberculosis protein (CFP10-ESAT6), human papilloma virus (HPV) protein (E7) and survivin, a protein commonly over-expressed in tumour cells. An epitope from ROP-OVA was cross-presented and detected by a CD8+ T cell receptor-like antibody (TCR like Ab). Human DCs pulsed with ROP-survivin activated CD8+ T cells. CD4-low PBMCs from HIV and TB co-infected patients recognized ROP-CFP10-ESAT6 compared to a soluble form of the antigen. Immunization of mice with ROP-survivin or ROP-HPV-E7 generated specific cellular immune responses and protected mice from inoculation with melanoma B16 cells expressing survivin or HPV-E7 proteins. Together these data provide evidence to support ROP as a central component of a new platform for therapeutic vaccines and diagnostics.

Evolutionarily conserved primary TNF sequences relate to its primitive functions in cell death induction.

TNF is a primitive protein that has emerged from more than 550 million years of evolution. Our bioinformatics study of TNF from nine different taxa in vertebrates revealed several conserved regions in the TNF sequence. By screening overlapping peptides derived from human TNF to determine their role in three different TNF-induced processes--apoptosis, necrosis and NF-κB stimulation--we found that TNF conserved regions are mostly related to cell death rather than NF-κB stimulation. Among the most conserved regions, peptides (P)12, P13 and P1213 (comprising P12 and P13) induced apoptosis, whereas P14, P15, P16 and P1516 (comprising P15 and P16) induced necrosis. Cell death induced by these peptides was not through binding to the TNF receptor. P16-induced necrosis was mainly through disruption of the cell membrane, whereas P1213-induced apoptosis involved activation of TRADD followed by formation of complex II. Finally, using a monoclonal antibody and a mutant TNF protein, we show that TNF-induced apoptosis is determined by a conserved linear sequence that corresponds to that within P1213. Our results reveal the determinant sequence that is key to the TNF primitive function of inducing apoptosis.

Immunization with different formulations of Mycobacterium tuberculosis antigen 85A induces immune responses with different specificity and protective efficacy.

To test the relative efficacy of CD4 and CD8T cells in mediating protective immunity to Mycobacterium tuberculosis (Mtb), we compared three immunization regimes designed to induce preferentially each subset. BALB/c mice were immunized intranasally (i.n.) or parenterally with antigen 85A either in a recombinant Adenoviral vector (Ad85A), as recombinant protein (r85A) or as a set of overlapping 15mer peptides (p85A). For the first time we show that i.n. immunization with overlapping 85A synthetic peptides as well as Ad85A or r85A can provide protection against Mtb challenge. For all forms of the antigen, i.n. induces greater protection against Mtb challenge than parenteral immunization. Ad85A induces a predominantly CD8T cell response against the 85A(70-78) epitope, r85A a CD4 response to 85A(99-118) and p85A a balanced CD4/CD8 response to the CD4 85A(99-118 )and CD8 85A(145-152) epitopes. Immune responses to CD4 85A(99-118) and CD8 85A(70-78) but not CD8 85A(145-152) are protective. Although Ad85A induces a strong response to the protective CD8 85A(70-78) epitope, we could not induce any response to this epitope by peptide immunization. These results show that although peptide immunization can induce protective immunity to Mtb challenge, it can also induce a response to a non-protective epitope in antigen 85A, indicating that the specificity of an immune response may be more important for protection against Mtb than its magnitude. These findings have important implications for the application of such vaccines in humans.

Comparing pooled peptides with intact protein for accessing cross-presentation pathways for protective CD8+ and CD4+ T cells.

To better understand the mechanisms of intracellular trafficking and presentation of exogenous peptides by antigen-presenting cells (APC), we compared the handling of overlapping 24-mer peptides from HIV Nef either mixed or covalently linked in tandem in one protein. Once internalized, peptides trafficked not only to endosomes but also to cytosol, and activated CD8(+) and CD4(+) T cells. In contrast, whole protein was found to traffic only to the endosomal compartments, and primarily activated CD4(+) T cells. Finally, with adjuvant, overlapping peptides were capable of protecting against lethal viral challenge, whereas the intact protein was less protective. These data suggest that overlapping long peptides are cross-presented through more varied intracellular routes and are more efficient in priming protective immunity than the whole protein.

Live attenuated Listeria monocytogenes expressing HIV Gag: immunogenicity in rhesus monkeys.

Induction of strong cellular immunity will be important for AIDS vaccine candidates. Natural infection with wild-type Listeria monocytogenes (Lm), an orally transmitted organism, is known to generate strong cellular immunity, thus raising the possibility that live attenuated Lm could serve as a vaccine vector. We sought to examine the potential of live attenuated Lm to induce cellular immune responses to HIV Gag. Rhesus macaques were immunized with Lmdd-gag that expresses HIV gag and lacks two genes in the D-alanine (D-ala) synthesis pathway. Without this key component of the bacterial cell wall, vaccine vector replication critically depends on exogenous D-ala. Lmdd-gag was given to animals either solely orally or by oral priming followed by intramuscular (i.m.) boosting; D-ala was co-administered with all vaccinations. Lmdd-gag and D-ala were well tolerated. Oral priming/oral boosting induced Gag-specific cellular immune responses, whereas oral priming/i.m. boosting induced systemic as well as mucosal anti-Gag antibodies. These results suggest that the route of vaccination may bias anti-Gag immune responses either towards T-helper type 1 (Th1) or Th2 responses; overall, our data show that live attenuated, recombinant Lmdd-gag is safe and immunogenic in primates.

Overlapping synthetic peptides as vaccines.

Several vaccine strategies aim to generate cell-mediated immunity (CMI) against microorganisms or tumors. While epitope-based vaccines offer advantages, knowledge of specific epitopes and frequency of major histocompatibility complex (MHC) alleles is required. Here we show that using promiscuous overlapping synthetic peptides (OSP) as immunogens generated peptide-specific CMI in all vaccinated outbred mice and in different strains of inbred mice; CMI responses also recognized viral proteins. OSP immunogens also induced CMI ex vivo in dendritic cell/T-cell cocultures involving cells from individuals with different HLA haplotypes. Thus, broad CMI was induced by OSP in different experimental settings, using different immunogens, without identifying either epitopes or MHC backgrounds of the vaccinees.

Schistosoma mansoni infection promotes SHIV clade C replication in rhesus macaques.

OBJECTIVE: To evaluate the hypothesis that parasitic infections that induce T-helper type 2 (Th2) immune responses, such as schistosomiasis, upregulate HIV-1 replication. DESIGN: The effect of concomitant Schistosoma mansoni infection was tested in a primate model of acute and chronic simian-human immunodeficiency virus (SHIV) infection in rhesus macaques using a novel SHIV strain encoding the R5 env gene of a primary HIV clade C isolate from sub-Saharan Africa. METHODS: S. mansoni-infected rhesus macaques and controls were exposed to SHIV to assess the effects of schistosomiasis on acute viral infection. Effects on chronic viral infection were evaluated by exposing virus-infected animals to parasites. S. mansoni infection was confirmed by the presence of parasite eggs in stool and eosinophilia. Viral RNA loads, cytokine and chemokine mRNA expression were measured by real time reverse transcription-PCR. RESULTS: S. mansoni coinfection increased the expression of Th2-associated cytokine responses and SHIV replication during both acute and chronic phases of SHIV infection. CONCLUSIONS: These results support the hypothesis that concomitant schistosomiasis upregulates replication of immunodeficiency viruses in coinfected hosts, raising the possibility that parasite-infected individuals may also be more susceptible to acquisition of HIV-1 infection.

Virus-specific CTL responses induced by an H-2K(d)-restricted, motif-negative 15-mer peptide from the fusion protein of respiratory syncytial virus.

We describe 15-mer peptide P8:F92-106 from the F protein of respiratory syncytial virus (RSV) that can act as an MHC class I-restricted (H-2K(d)) epitope for RSV-specific CD8(+) CTL. This peptide is interesting because not only is it the first murine CTL epitope to be identified in the F protein but also because it does not contain a known allele-specific motif, as all 15 amino acids appear to be required for effective presentation to CTL. In in vitro MHC class I refolding experiments, peptide P8:F92-106 induced complex formation with H-2K(d) heavy chains and beta2-microglobulin. Immunization of BALB/c mice with P8:F92-106 resulted in the induction of peptide and RSV-specific CTL responses as well as peptide-specific proliferative responses. Following intranasal challenge with RSV, P8:F92-106-immunized mice showed a significant reduction in viral load in the lungs compared to that seen in unimmunized mice. Furthermore, passive transfer of purified CD8(+) lymphocytes into BALB/c scid mice prior to challenge with RSV also resulted in a reduction in the virus load in lungs of challenged mice. These results indicate the potential of synthetic peptide epitopes for the induction of protective immune responses against RSV infection.