Search Results (281)

Background: hMPXV poses a major public health risk due to its human-to-human transmissibility, severe complications, especially in immunocompromised individuals, and global spread, necessitating effective surveillance and stringent prophylactic measures to mitigate its colossal impact. Objective: The study aimed to annotate hMPXV(IMV) proteins to propose a potential reverse vaccinology-based vaccine against hMPXV. Methods: The target MPXV(IMV) protein’s sequences, formatted in FASTA, were sourced from genome/proteome databases (BV-BRC and UniProt) (accessed on 6 November 2024), followed by CD-Hit-based redundancy removal. Epitope prediction for B-cells (lymphocytes), cytotoxic T-cells or cytotoxic T-lymphocytes (CTLs), and helper T-cells (HTLs) was executed using ABCpred, IEDB’s ANNs 4.0, and an artificial neural network-based alignment tool (NN-align 2.3)/ML-based tool (NetMHCII 2.3). Various immunoinformatics filters (antigenicity, toxicity, and allergenicity) were applied to substantiate the potency and safety of the formulated vaccine candidate. The constructed vaccine’s physiochemical and structural features (secondary and tertiary), with structural stability (confirmed by molecular docking followed by dynamic simulation with TLRs (TLR4 & TLR2) and MHCs), were determined. Additionally, cloning (using pET-28a(+) vector) was conducted to verify the vaccine’s expression potential and translation efficiency. The construct’s population coverage was also ascertained. Results: The MPXV-2-Beta vaccine constructs, of the six initially designed constructs, was identified as the most promising candidate, signifying nonallergenic profile and nontoxic features, with a predicted antigenicity score (PAS) = 0.7202, 407 residues, a molecular weight of 43,102.1 Da, pI of 9.2, and favorable stability parameters (AI: 65.65, GRAVY: −0.597, I-i: 25.92). It showed high solubility (score: 0.942). The ProSA Z-score of −9.38 confirmed the structural stability, reliability, and precision of the MPXV-2-Beta 3D model, which is comparable to experimental structures. Furthermore, 98.8% of all the residues nested within favored or allowed regions in a critical Ramachandran plot signified the model’s exceptional structural integrity and quality. Docking and dynamic simulation of MPXV-2-Beta with TLRs (TLR4 & TLR2) and MHCs demonstrated stiffer docking stability (strong polar and nonpolar interaction) and negative eigenvalue value (during dynamic simulation), suggesting its ability to enhance immune receptor activation under physiological conditions. MPXV-2-Beta was predicted to trigger a robust immune response (IR) with comprehensive world population coverage (98.55%, SD = 10.41). Conclusions: Based on the evaluated parameters, the MPXV-2-Beta designed in this study exhibited significant potential as an effective candidate against hMPXV. This study establishes a foundation for developing an efficient vaccine against hMPXV, requiring further experimental and clinical validation to confirm computational findings. Full article

Background/Objectives: Nucleic acid-based anticancer vaccines are becoming a very active field in the fight against cancer. Here, our goal was to generate an oral DNA vaccine targeting the angiogenic peptide, proadrenomedullin N-terminal 20 peptide (PAMP). Methods: An expression plasmid (PcPAMP) was generated by fusing the tetanus toxin epitopes P2 and P30 to the mouse PAMP sequence to counteract self-tolerance, and the empty plasmid was used as a negative control (PcNeg). The plasmids were introduced into Salmonella typhimurium bacteria that were then transformed into bacterial ghosts. C57BL/6J mice were orally immunized with the ghosts five times at 2-week intervals. Then, B16-F10 melanoma cells were injected into the tail vein to generate lung metastases. Furthermore, naïve CD4⁺ T cells were exposed to PAMP, and their secretome was analyzed by proximity extension assays. Results: Significant levels of anti-PAMP immunoglobulins were detected in the blood of PcPAMP-vaccinated mice and their levels of spleen CD8⁺ T cells were significantly higher than in those treated with PcNeg, indicating that self-tolerance was effectively broken. Although the number and size of lung metastases was similar between both experimental groups, there was a significant reduction in intratumoral angiogenesis and in cancer cell proliferation index in the PcPAMP group. Furthermore, these animals showed an intense infiltration of lymphocytes, including regulatory T cells, and M2-like macrophages into the metastases, that was not evident in the PcNeg group. In addition, PAMP induced upregulation of IL1β, IL6, IL7, IL12, IL27, TNFα, and FGF21, and downregulation of IL16 in naïve CD4⁺ T cells. Conclusions: Although the vaccine was not effective in reducing tumor growth, new proliferative and immune functions have been described for PAMP. These new functions include induction of melanoma proliferation and modulation of lymphocyte and macrophage tumor infiltration dynamics. Full article

Staphylococcus aureus is a leading cause of severe infections in humans and animals, and the emergence of multidrug-resistant strains highlights the need to develop effective vaccines to prevent such diseases. Epitope-based vaccines use short antigen-derived peptides corresponding to immune epitopes, which are administered to trigger protective humoral and cellular immune responses. In this study, in silico MHC affinity measurement methods were used to predict possible binding regions, and five 20-mer synthetic TRAP peptides (TRAPP) were synthesized. Epitope-based vaccines, named PT and PTR, incorporating the identified CD4⁺ T and B cell epitopes, were constructed. Peptides TRAP_20–39 and TRAP_94–113 elicited significant peptide-stimulated T-cell proliferation responses in vivo. Additionally, high levels of IFN-γ and IL-17A, along with moderate levels of IL-4, were detected in ex vivo stimulated CD4⁺ T cells isolated from rTRAP- and TRAPP-immunized mice, suggesting that these peptides are classified as Th1 and Th17 epitopes. Immunization with PT or PTR induces robust humoral and cellular immune responses. Moreover, the epitope-based vaccine, PT, exhibited a stronger protective immune response than the intact TRAP in a murine systemic S. aureus infection model. Based on the results presented herein, an epitope-based vaccine is a promising and potentially more effective candidate. Full article

Background: Brucellosis poses a significant public health challenge, necessitating effective vaccine development. Current vaccines have limitations such as safety concerns and inadequate mucosal immunity. This study aims to develop an FcRn-targeted mucosal Brucella vaccine by fusing the human Fc domain with Brucella’s multi-epitope protein (MEV), proposing a novel approach for human brucellosis prevention. Methods: The study developed a recombinant antigen (h-tFc-MEV) through computational analyses to validate antigenicity, structural stability, solubility, and allergenic potential. Molecular simulations confirmed FcRn binding. The vaccine was delivered orally via chitosan nanoparticles in murine models. Immunization was compared to MEV-only immunization. Post-challenge assessments were conducted to evaluate protection against Brucella colonization. Mechanistic studies investigated dendritic cell activation and antigen presentation. Results: Computational analyses showed that the antigen had favorable properties without allergenic potential. Molecular simulations demonstrated robust FcRn binding. In murine models, oral delivery elicited enhanced systemic immunity with elevated serum IgG titers and amplified CD4+/CD8+ T-cell ratios compared to MEV-only immunization. Mucosal immunity was evidenced by significant IgA upregulation across multiple tracts. Long-term immune memory persisted for six months. Post-challenge assessments revealed markedly reduced Brucella colonization in visceral organs. Mechanistic studies identified FcRn-mediated dendritic cell activation through enhanced MHC-II expression and antigen presentation efficiency. Conclusions: The FcRn-targeted strategy establishes concurrent mucosal and systemic protective immunity against Brucella infection. This novel vaccine candidate shows potential for effective human brucellosis prevention, offering a promising approach to address the limitations of current vaccines. Full article

Hypersensitivity reactions are dysregulated and potentially devastating immune responses, characterized by a tendency to become chronic. They target either self-proteins or harmless foreign proteins and are driven by both T and B cells. Although numerous symptomatic treatment options for hypersensitivity reactions have been established over recent decades, only a few antigen-specific, causal approaches capable of specifically targeting the pathogenic autoreactive T and/or B cells have been developed. Among these are cell-based treatment modalities involving chimeric antigen receptor (CAR)- or chimeric autoantibody-receptor (CAAR)-expressing cells. These therapies utilize B- or T-cell antigens, presented as B-cell epitopes or peptide-major histocompatibility complexes (pMHCs) to serve as bait. The latter are coupled to potent activation domains derived from the TCR/CD3 complex itself, such as the zeta or CD3 chains, as well as domains from bona fide co-stimulatory molecules (e.g., CD28, 4-1BB). Recent in vitro and in vivo studies have demonstrated the therapeutic potential of these ATMP-based strategies in eliminating autoreactive lymphocytes and alleviating hypersensitivity reactions. This systematic review provides a comprehensive overview of the current status of antigen-specific CAR and CAAR T-cell therapies, highlighting novel directions as well as the ongoing challenges within this promising research field. Full article

Background/Objectives: In the past, FhSAP-2, an 11.5 kDa recombinant protein belonging to the Fasciola hepatica saposin-like/NK-lysin family, has been shown to induce over 60% partial protection in immunized rabbits and mice when challenged with F. hepatica metacercariae. However, despite FhSAP-2 being a promising vaccine candidate, its hydrophobic nature has made its purification a challenging process. The present study aimed to determine whether a modified 9.8 kDa variant of protein (mFhSAP-2), lacking a string of 16 hydrophobic amino acids at the amino terminus and a dominant Th1 epitope, could retain its immunogenic and Th1-inducing properties. Methods: RAW264.7 cells were stimulated with mFhSAP-2, and TNFα levels were determined. C57BL/6 mice were immunized with mFhSAP-2 alone or emulsified with Montanide ISA50. Total anti-mFhSAP-2 IgG subtypes, along with their avidity and titers, were measured using ELISA. The T cell proliferation index and levels of CD4+/CD8+ and IFNγ/IL-4 ratios were determined. Results: In vitro, mFhSAP-2 induced dose-dependent TNFα production in RAW264.7 cells. In vivo, mice immunized with mFhSAP-2 or mFhSAP-2+ISA50 developed high-avidity IgG2a and IgG2c antibodies at levels that were significantly higher than IgG1 antibody levels. However, the mFhSAP-2+ISA50 formulation induced higher and more homogenous antibody titers than mFhSAP-2, suggesting that an adjuvant may be required to enhance mFhSAP-2 immunogenicity. Immunization with mFhSAP-2+ISA50 also induced significantly higher activated CD4+/CD8+ T cell ratios and IFNγ/IL-4 ratios compared to naïve mice. Conclusions: Our results demonstrate that mFhSAP-2 retained its immunogenicity and Th1-polarizing properties, which were enhanced by the Montanide ISA50 adjuvant. The present study highlights the feasibility of inducing Th1-associated immune responses in mice using mFhSAP-2 as an antigen. Further studies are required to assess the potential application of the mFhSAP-2+ISA50 formulation as a vaccine against F. hepatica in natural hosts such as cattle and sheep, which could contribute to improved control and aid in the prevention and eradication of F. hepatica infection. Full article

Necrotic enteritis (NE), caused by pathogenic Clostridium perfringens, poses a significant threat to global poultry health, with estimated annual losses exceeding USD 6 billion. The rising incidence of NE has been associated with the reduced use of antibiotic growth promoters, underscoring the urgent need for alternative control measures such as vaccination. Collagen adhesin protein (CNA), a key virulence factor in NE pathogenesis, represents a promising vaccine target. The US Food and Drug Administration has begun phasing out animal testing requirements for biologics and monoclonal antibody drugs. In this study, a computational multi-epitope vaccine (MEV) targeting CNA was designed by integrating predicted Cluster of Differentiation (CD)4⁺ helper T lymphocyte (Th), CD8⁺ cytotoxic T lymphocyte (CTL), and B-cell epitopes. Bioinformatics tools were used to identify immunogenic, antigenic, and non-allergenic epitopes assembled into a 115-amino-acid peptide vaccine construct. The candidate demonstrated strong stability and solubility. In silico immune simulation predicted robust immune responses, including elevated IgG and IgM antibody levels, plasma cell proliferation, Th memory formation, and CTL activation, comparable to responses elicited by a full-length CNA. These findings support the potential of the designed peptide as one of the multiple effective NE vaccine components, offering a promising alternative to antibiotic-based approaches in poultry disease management. Full article

The impact of hepatitis B virus (HBV) diversity and evolution on disease progression is not well-understood. This study aims to compare intra-individual viral evolution in two groups of chronic hepatitis B (CHB) patients, using antiviral treatment initiation as a measure of lack of immunological control. From the Danish Database for Hepatitis B and C (DANHEP), 25 CHB patients were included; 14 with antiviral treatment initiation (TI group), and 11 without (NTI group). For each patient, three serial plasma samples taken before potential treatment initiation were selected. HBV DNA was amplified by PCR and analyzed by next-generation sequencing. HBV DNA and alanine transaminase were elevated in the TI group throughout the study period. Significantly higher substitution rates in the NTI group versus the TI group were found both within the viral population and at consensus level. Putative predicted CD8⁺ T cell epitopes contained significantly more substitutions in the NTI group. Genome-wide association analysis revealed several amino acid residues in the HBV genome associated with treatment initiation. This study shows that HBV has a higher rate of substitutions in CHB patients not requiring treatment. This could be linked to host immune pressure leading to disease control. Full article

Chagas disease, caused by the protozoan Trypanosoma cruzi (T. cruzi), is the most significant neglected tropical disease affecting individuals in the Americas. Currently, available drugs, such as nifurtimox and benznidazole (BZN), are both toxic and ineffective in the chronic phase of the disease. A promising alternative is the development of a Chagas disease vaccine, although this effort is hampered by the complexity of the parasite and HLA polymorphisms. In addition, the activation of epitope-specific CD8⁺ T cells is critical to conferring a robust cell-mediated immune response and protection by producing IFN-γ and perforin. Thus, the antigen (s) for the development of a Chagas vaccine or immunotherapy must include CD8⁺ T cell epitopes. In this study, we aimed to develop a multi-epitope recombinant protein as a novel human vaccine for Chagas disease. Sixteen database programs were used to predict de novo 40 potential epitopes for the HLA-A*02:01 allele. Nine out of the 40 predicted epitopes were able to elicit IFN-γ production in Peripheral Blood Mononuclear Cells (PBMCs) from Chagas patients. Molecular docking revealed a good binding affinity among the epitopes with diverse HLA molecules. Therefore, a recombinant multi-epitope protein including these nine T. cruzi CD8⁺ epitopes was expressed and demonstrated to recall an antigen-specific immune response in ex-vivo assays using PBMCs from Chagas patients with the HLA-A*02 allele. These findings support the development of this multi-epitope protein as a promising candidate human vaccine against Chagas disease. Full article

Background/Objectives: The revolution for the treatment of melanoma came with the approval of checkpoint blockade antibodies. However, a substantial proportion of patients show primary or secondary resistance to this type of immunotherapy, indicating the need for alternative therapeutic strategies. Dendritic cells (DCs) of the skin are prime targets for vaccination approaches due to their potential to prime naïve T cells and their accessibility. This study aimed to develop and evaluate novel vaccines targeting the C-type lectin receptor DEC-205 to deliver melanoma-associated antigenic peptides to skin DCs. Methods: We cloned MHC-I-restricted peptides from the glycoprotein (gp)100_25–33 and Tyrosinase-related protein (trp)2_180–188 into the DEC-205 antibody sequence with modified peptide cutting sites from the OVA_257–264 SIINFEKL peptide. We tested their potential to induce CD8⁺ T cell responses in both in vitro and in vivo settings. Tumor growth inhibition was evaluated in the transplantable B16.OVA melanoma murine model using a multi-epitope DC-based vaccine combining both peptides. Results: The cross-presentation of both gp100 and trp2 peptides was confirmed in vivo when peptide sequences were flanked by the OVA_257–264 peptide cutting sites. Moreover, the combination of both antigenic peptides into a multi-epitope DC vaccine was required to inhibit B16.OVA melanoma growth. Conclusions: Our findings suggest that a DC-targeted vaccination approach using multiple epitopes deriving from melanoma antigens could represent a promising strategy for melanoma therapy. Full article

Background/Objectives: Immunotherapy has shown promising results in some cancers, but its efficacy remains limited in pancreatic ductal adenocarcinoma (PDAC). Vaccines in nanoparticle form (nanovaccines) can incorporate immunostimulating components to induce a potent immune response. As mesothelin (MSLN) is a tumor-associated antigen overexpressed in PDAC, we evaluated the effect of MSLN nanovaccine in a syngeneic orthotopic KPC-PDAC mouse model. Methods: An MSLN peptide combining three MSLN epitopes and two adjuvants, poly I:C and R848, was encapsulated in PLGA–chitosan nanoparticles to generate the nanovaccine. Results: The MSLN nanovaccine was successfully taken up by dendritic cells in vitro and was found in inguinal lymph nodes 24 h after subcutaneous injection into C57BL/6 mice. Nanovaccine re-stimulation of splenocytes from vaccinated mice led to increased levels of interferon-γ in vitro compared to unstimulated splenocytes. Higher levels of MSLN-specific IgM and IgG antibodies were detected in the serum of vaccinated mice compared to that of control mice. Three vaccination regimens were tested: a prophylactic scheme that included vaccination before tumor induction and two therapeutic schemes involving early and late vaccination after tumor cell inoculation. MSLN nanovaccination inhibited KPC tumor progression and metastasis and induced higher CD8⁺ T cell infiltration in the tumor that developed in response to prophylactic and early therapeutic schedules but not in response to a later vaccination approach. Although the nanovaccine treatment elicited higher humoral and cellular antigen-specific responses in tumor-bearing mice for both vaccination strategies, the therapeutic vaccination also increased the expression of exhaustion markers in CD8⁺ T cells. Conclusions: Our results support the relevance of an MSLN-based nanovaccine as a new immunotherapy treatment for PDAC and propose an innovative method of vaccine delivery using NPs. Full article

Background: Plasma cell myeloma is an incurable malignancy of clonal plasma cells. Recent success in immunotherapeutic strategies has altered the landscape of myeloma treatment. Daratumumab is an anti-CD38 IgG kappa monoclonal antibody that has shown great efficacy in the treatment of myeloma. However, Daratumumab brought with it new challenges in post-therapeutic laboratory assessment, including therapeutic antibody interference with serum protein electrophoresis and serum immunofixation electrophoresis assays. In this study, we highlight the interference identified in post-therapeutic flow cytometry analysis related to bound Daratumumab on normal hematopoietic cells. We also highlight the methods of detection of residual plasma cell neoplasm, post-Daratumumab therapy.: A total of 28 patients with refractory plasma cell myeloma who received Daratumumab (2016–2018) were included in this study. Flow cytometry was performed using 4- or 10-color antibody panels (BD FASC Canto) and analyzed by cluster analysis (Cytopaint Classic software) using four tube panels including VS38c for measurable residual disease (MRD) testing. Pretreatment and post-Daratumumab follow-up bone marrow flow cytometry samples were analyzed. In addition, 10 multiple myeloma patient samples were reflexed to multi-epitope CD38 analysis by flow cytometric analysis of post-Daratumumab residual disease. When discussing CD38 expression, we will refer to CD38 as being detected by conventional reagents. Results: All post-Daratumumab-treated cases (100%) showed negative staining for CD38 using conventional reagents on all plasma cells in the specimens. MRD testing successfully identified small clonal plasma cell populations using VS38C and multi-epitope CD38 (meCD38) antibodies, despite the absence of demonstrable CD38 expression. Additionally, all cases exhibited weak kappa light chain staining on hematogones, attributed to the binding of Daratumumab kappa monoclonal antibody. This interaction can create the appearance of a CD10+ monotypic B-cell population. We also noted diminished CD38 staining on myeloblasts, resulting in an atypical CD34/CD38 staining pattern. This alteration could potentially be misinterpreted as indicative of a myelodysplastic neoplasm (MDS). Furthermore, decreased staining of CD38 was noted on T cells, natural killer (NK) cells, basophils, monocytes, and plasmacytoid dendritic cells. Conclusions: With the emergence of successfully targeted immunotherapies, such as anti-CD38 antibodies, it is important to understand and correctly interpret variations in flow cytometry that may arise from the therapy. Hematogones exhibit high-intensity levels of CD38 expression; thus, Daratumumab binds to them, creating the appearance of kappa expression on all hematogones. Stage I/early stage II hematogones normally lack surface immunoglobulin light chain expression, but in the presence of Daratumumab, they appear to be a CD10(+) monotypic population of B cells. The misinterpretation of these normal cells as a CD10(+) B-cell clone can lead to inaccurate assessment, unnecessary bone marrow immunohistochemical evaluation, and unwarranted anxiety. Additionally, artefacts on various other hematopoietic cells can result in inaccurate assessments of immunophenotypic aberrancy due to binding of the drug. This may lead to the false interpretation of a secondary/therapy-related myeloid neoplasm. This study highlights in detail the interferences that must be considered when assessing residual disease in the era of targeted drug therapies. Full article

CD6 is a cell surface protein expressed by T cells, a subset of NK cells, a small population of B cells, and thymocytes. CD6 has multiple and complex functions due to its distinct functional epitopes that mediate interactions with several ligands including CD166 (ALCAM) and CD318 (CDCP1). An additional molecule, CD44, is being investigated as a potential new ligand of CD6. CD6 plays critical roles in lymphocyte activation, proliferation, and adhesion to antigen-presenting, epithelial, and cancer cells. CD6 is a risk gene for multiple autoimmune diseases, possibly related to its numerous roles in regulating CD4+T-cell responses. Additionally, CD6 is a potential target for cancer immunotherapy. Here, we dissect the role of CD6 in the pathogenesis of more than 15 diseases and discuss recent data supporting the use of CD6-targeted therapy in humans. Full article

Background: The rapid advancement of the pandemic caused by SARS-CoV-2 and its variants reinforced the importance of developing easy-to-edit vaccines with fast production, such as multi-epitope DNA vaccines. The present study aimed to construct a synthetic antigen multi-epitope SARS-CoV-2 to produce a DNA vaccine. Methods: A database of previously predicted Spike and Nucleocapsid protein epitopes was created, and these epitopes were analyzed for immunogenicity, conservation, population coverage, and molecular docking. Results: A synthetic antigen with 15 epitopes considered immunogenic, conserved even in the face of variants and that were able to anchor themselves in the appropriate HLA site, together had more than 90% worldwide coverage. A multi-epitope construct was developed with the sequences of these peptides separated from each other by linkers, cloned into the pVAX1 vector. This construct was evaluated in vivo as a DNA vaccine and elicited T CD4+ and T CD8+ cell expansion in the blood and spleen. In hematological analyses, there was an increase in lymphocytes, monocytes, and neutrophils between the two doses. Furthermore, based on histopathological analysis, the vaccines did not cause any damage to the organs analyzed. Conclusions: The present study generated a multi-epitope synthetic vaccine antigen capable of generating antibody-mediated and cellular immune responses. Full article

SARS-CoV-2 continues to be a major global health threat. In this study, we performed a comprehensive meta-analysis on the epitopes of SARS-CoV-2, revealing its immunological landscape. Furthermore, using Shannon entropy for sequence conservation analysis and structural network-based methods identified candidate epitopes that are highly conserved and evolutionarily constrained in SARS-CoV-2 and other zoonotic coronaviruses. Finally, the population coverage of T cell epitopes was analyzed. The results highlighted regions within each SARS-CoV-2 protein where the immunological activity of antibodies, CD4⁺, and CD8⁺ T cell responses was predominantly concentrated. Sequence-based correlation analysis found that epitopes recognized by B cells and CD4⁺ T cells showed a positive correlation with high viral variability, and these high variability regions were typically linked to robust immune responses. Conversely, epitopes recognized by CD8⁺ T cells exhibited a negative correlation with high variability. From a structural network degree perspective, no clear correlation was identified between B cell antibody epitopes and CD4⁺ T cell reactivity with the degree of residue network connectivity. However, a significant positive correlation was observed between CD8⁺ T cell reactivity and the degree of residue network connectivity. By integrating sequence Shannon entropy and structural network correlation analysis, we pinpointed highly conserved and evolutionarily constrained SARS-CoV-2 candidate epitopes. Furthermore, we utilized immunoinformatics to assess the conservation of SARS-CoV-2 within coronaviruses and the population coverage of these epitopes. Our analysis uncovered key immune responses linked to preventing viral infection and viral clearance, emphasized areas of interest for broad-spectrum SARS-CoV-2 vaccine development, and offered insights for future research and clinical applications. Full article