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Nature Communications Sep 2023Invasion of human erythrocytes by Plasmodium falciparum (Pf) merozoites relies on the interaction between two parasite proteins: apical membrane antigen 1 (AMA1) and...
Invasion of human erythrocytes by Plasmodium falciparum (Pf) merozoites relies on the interaction between two parasite proteins: apical membrane antigen 1 (AMA1) and rhoptry neck protein 2 (RON2). While antibodies to AMA1 provide limited protection against Pf in non-human primate malaria models, clinical trials using recombinant AMA1 alone (apoAMA1) yielded no protection due to insufficient functional antibodies. Immunization with AMA1 bound to RON2L, a 49-amino acid peptide from its ligand RON2, has shown superior protection by increasing the proportion of neutralizing antibodies. However, this approach relies on the formation of a complex in solution between the two vaccine components. To advance vaccine development, here we engineered chimeric antigens by replacing the AMA1 DII loop, displaced upon ligand binding, with RON2L. Structural analysis confirmed that the fusion chimera (Fusion-F) closely mimics the binary AMA1-RON2L complex. Immunization studies in female rats demonstrated that Fusion-F immune sera, but not purified IgG, neutralized vaccine-type parasites more efficiently compared to apoAMA1, despite lower overall anti-AMA1 titers. Interestingly, Fusion-F immunization enhanced antibodies targeting conserved epitopes on AMA1, leading to increased neutralization of non-vaccine type parasites. Identifying these cross-neutralizing antibody epitopes holds promise for developing an effective, strain-transcending malaria vaccine.
Topics: Female; Animals; Rats; Broadly Neutralizing Antibodies; Ligands; Cell Membrane; Antibodies, Neutralizing; Epitopes
PubMed: 37735574
DOI: 10.1038/s41467-023-41636-5 -
Translational Oncology Dec 2023The biomarkers of immune checkpoint inhibitors (ICIs) efficacy and safety are still urgently needed. As cytokines are easily detected and monitored in circulation, they...
BACKGROUND
The biomarkers of immune checkpoint inhibitors (ICIs) efficacy and safety are still urgently needed. As cytokines are easily detected and monitored in circulation, they could be used as potential predictors of response and immune-related adverse events (irAEs) for ICIs therapy.
METHODS
The levels of TGF-β, IFN-γ, IL-6, IL-8, IL-10 were measured in sera and plasma by ELISA method of 30 healthy controls (HC) and 32 BRAF wild type (wt) MM patients before and after every 12 weeks of Pembrolizumab, PD-1 inhibitor, until one year or disease progression (DP).
RESULTS
Higher pretherapy levels of circulating TGF-β, IFN-γ, IL-6, and IL-10 were shown in MM patients compared to HC. In patients with disease control, TGF-β and IL-6 first decreased during the therapy, while then they started to successively increase reaching the initial values by the end of the follow up. Furthermore, in this group of patients IFN-γ increased, while IL-8 and IL-10 decreased at final points of the follow up. In patients with DP IL-6 increased at the time of progression, while IL-8 decreased when the best response was achieved. In patients with pseudoprogression IL-6 and IL-10 significantly increased compared to the pretreatment values. Melanoma patients with irAEs had increased baseline values of TGF-β, IFN-γ, IL-6, and IL-10 compared to HC. However, no significant changes in cytokines levels were found in these patients during therapy.
CONCLUSIONS
Inflammatory cytokines monitoring in circulation of BRAFwt MM patients could help in the selection of patients who will have the benefit from Pembrolizumab therapy.
PubMed: 37806113
DOI: 10.1016/j.tranon.2023.101799 -
Transplantation Reviews (Orlando, Fla.) Dec 2023Recommendations of the use of antibody induction treatments in kidney transplant recipients (KTR) are based on moderate quality and historical studies. This systematic... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Recommendations of the use of antibody induction treatments in kidney transplant recipients (KTR) are based on moderate quality and historical studies. This systematic review aims to reevaluate, based on actual studies, the effects of different antibody preparations when used in specific KTR subgroups.
METHODS
We searched MEDLINE and CENTRAL and selected randomized controlled trials (RCT) and observational studies looking at different antibody preparations used as induction in KTR. Comparisons were categorized into different KTR subgroups: standard, high risk of rejection, high risk of delayed graft function (DGF), living donor, and elderly KTR. Two authors independently assessed the risk of bias.
RESULTS
Thirty-seven RCT and 99 observational studies were finally included. Compared to anti-interleukin-2-receptor antibodies (IL2RA), anti-thymocyte globulin (ATG) reduced the risk of acute rejection at two years in standard KTR (RR 0.74, 95%CI 0.61-0.89) and high risk of rejection KTR (RR 0.55, 95%CI 0.43-0.72), but without decreasing the risk of graft loss. We did not find significant differences comparing ATG vs. alemtuzumab or different ATG dosages in any KTR group.
CONCLUSIONS
Despite many studies carried out on induction treatment in KTR, their heterogeneity and short follow-up preclude definitive conclusions to determine the optimal induction therapy. Compared with IL2RA, ATG reduced rejection in standard-risk, highly sensitized, and living donor graft recipients, but not in high DGF risk or elderly recipients. More studies are needed to demonstrate beneficial effects in other KTR subgroups and overall patient and graft survival.
Topics: Humans; Aged; Antilymphocyte Serum; Immunosuppressive Agents; Kidney Transplantation; Alemtuzumab; Antibodies; Graft Rejection; Lymphocytes; Transplant Recipients; Graft Survival
PubMed: 37774445
DOI: 10.1016/j.trre.2023.100795 -
Blood Cancer Journal Feb 2024The use of post-transplantation cyclophosphamide (PTCy) for graft-versus-host disease (GVHD) prophylaxis is not established after reduced intensity conditioning (RIC)... (Randomized Controlled Trial)
Randomized Controlled Trial
Post-transplant cyclophosphamide versus anti-thymocyte globulin after reduced intensity peripheral blood allogeneic cell transplantation in recipients of matched sibling or 10/10 HLA matched unrelated donors: final analysis of a randomized, open-label, multicenter, phase 2 trial.
The use of post-transplantation cyclophosphamide (PTCy) for graft-versus-host disease (GVHD) prophylaxis is not established after reduced intensity conditioning (RIC) hematopoietic stem cell transplantation (HSCT) from fully matched donors. This was a randomized, open-label, multicenter, phase 2 trial. All patients received a RIC regimen with fludarabine, intravenous busulfan for 2 days (Flu-Bu2), and a peripheral blood stem cell (PBSC) graft from a matched related or 10/10 HLA-matched unrelated donor. Patients were randomly assigned to receive anti-thymocyte globulin (ATG) 5 mg/kg plus standard GVHD prophylaxis or PTCy 50 mg/kg/d at days +3 and +4 plus standard GVHD prophylaxis. The primary endpoint was the composite endpoint of GVHD- and relapse-free survival (GRFS) at 12 months after HSCT. Eighty-nine patients were randomly assigned to receive either PTCy or control prophylaxis with ATG. At 12 months, disease-free survival was 65.9% in the PTCy group and 67.6% in the ATG group (P = 0.99). Cumulative incidence of relapse, non-relapse mortality, and overall survival were also comparable in the two groups. GRFS at 12 months was 54.5% in the PTCy group versus 43.2% in the ATG group (P = 0.27). The median time to neutrophil and platelet count recovery was significantly longer in the PTCy group compared to the ATG group. Except for day +30, where EORTC QLQ-C30 scores were significantly lower in the PTCy compared to the ATG group, the evolution with time was not different between the two groups. Although the primary objective was not met, PTCy is effective for GVHD prophylaxis in patients receiving Flu-Bu2 conditioning with a PBSC graft from a fully matched donor and was well tolerated in term of adverse events and quality of life. This trial was registered at clinicaltrials.gov: NCT02876679.
Topics: Humans; Antilymphocyte Serum; Unrelated Donors; Siblings; Quality of Life; Cyclophosphamide; Hematopoietic Stem Cell Transplantation; Graft vs Host Disease; Retrospective Studies
PubMed: 38374026
DOI: 10.1038/s41408-024-00990-3 -
Medical Journal of the Islamic Republic... 2023Hydatidosis, a chronic zoonotic disease, has a distribution worldwide and is caused by the larval stage of the Echinococcus helminth. The Dot-ELISA test can diagnose...
BACKGROUND
Hydatidosis, a chronic zoonotic disease, has a distribution worldwide and is caused by the larval stage of the Echinococcus helminth. The Dot-ELISA test can diagnose hydatidosis quickly and accurately. Additionally, unlike other hydatid disease tests now used, this quick and affordable enzyme immunoassay is very serum-conservative and antigen-conservative, needing just nanogram levels of parasite antigen.
METHODS
In the present cross-sectional study, crude and B antigens of hydatid cyst fluid were obtained to diagnose human hydatidosis using CIEP (Counter Immunoelectrophoresis), ELISA (Enzyme-linked Immuno Sorbent assay), and Dot- ELISA (Dot Enzyme linked Immuno Sorbent Assay) methods. Infected liver with a hydatid cyst was collected from Tehran's slaughterhouses to prepare cyst fluid in different stages. After extracting and purifying the Cyst fluid, it is centrifuged at 4ºc, then prepared to concentrate. The study also included sera from hydatidosis (n=60), samples of helminth parasites (n=55), fascioliasis (n=35), toxocariasis (n=20) and negative control (n=35) were tested by CIEP (Counter Immunoelectrophoresis), ELISA (Enzyme-linked Immune Sorbent assay), and Dot- ELISA (Dot Enzyme linked Immuno Sorbent Assay) methods. All statistical analyses were performed using Statistical Package for the Social Sciences (SPSS) for Windows release 25.0 (SPSS Inc., Chicago, IL, USA).
RESULTS
Crude antigen of hydatid cyst showed a specificity of 76.7%, a sensitivity of 93.3% using the ELISA method, and B antigen showed a specificity of 96.7% and sensitivity of 88.3% using the same method. The crude antigen of the hydatid cyst exhibited a specificity of 68.9% and a sensitivity of 86.7% using CIEP. The B antigen showed a specificity of 87.8% and sensitivity of 83.3% using the same method.The crude antigen of hydatid cyst having serum dilution at 1:800 exhibited a specificity of 83.3% and sensitivity of 100% using the Dot-ELISA method and B antigen having serum dilution at 1:800 serum showed a specificity of 100% and sensitivity of 98.3% using the same method. The results of this finding showed that B antigen has the maximum specificity to diagnose hydatid test using the Dot- ELISA method.
CONCLUSION
Hydatid cysts present with varied symptomatology. History of exposure to infected animals may not be present. A high degree of clinical suspicion combined with meticulous history and clinical examination supported by laboratory investigations are required for its diagnosis. The Dot-ELISA system with native antigen B is a viable approach for the immunodiagnosis of human hydatidosis that is preferred to infection.
PubMed: 37655067
DOI: 10.47176/mjiri.37.87 -
Frontiers in Immunology 2023The evolution of novel SARS-CoV-2 variants significantly affects vaccine effectiveness. While these effects can only be studied retrospectively, neutralizing antibody...
INTRODUCTION
The evolution of novel SARS-CoV-2 variants significantly affects vaccine effectiveness. While these effects can only be studied retrospectively, neutralizing antibody titers are most used as correlates of protection. However, studies assessing neutralizing antibody titers often show heterogeneous data.
METHODS
To address this, we investigated assay variance and identified virus infection time and dose as factors affecting assay robustness. We next measured neutralization against Omicron sub-variants in cohorts with hybrid or vaccine induced immunity, identifying a gradient of immune escape potential. To evaluate the effect of individual mutations on this immune escape potential of Omicron variants, we systematically assessed the effect of each individual mutation specific to Omicron BA.1, BA.2, BA.2.12.1, and BA.4/5.
RESULTS
We cloned a library of pseudo-viruses expressing spikes with single point mutations, and subjected it to pooled sera from vaccinated hosts, thereby identifying multiple mutations that independently affect neutralization potency.
DISCUSSION
These data might help to predict antigenic features of novel viral variants carrying these mutations and support the development of broad monoclonal antibodies.
Topics: Humans; Retrospective Studies; SARS-CoV-2; COVID-19; Mutation; Vaccination; Antibodies, Neutralizing
PubMed: 38022629
DOI: 10.3389/fimmu.2023.1288794 -
Frontiers in Immunology 2023Antibody mediated rejection (ABMR) is a major factor limiting outcome after organ transplantation. Anti-HLA donor-specific antibodies (DSA) of the IgG isotype are mainly...
INTRODUCTION
Antibody mediated rejection (ABMR) is a major factor limiting outcome after organ transplantation. Anti-HLA donor-specific antibodies (DSA) of the IgG isotype are mainly responsible for ABMR. Recently DSA of the IgE isotype were demonstrated in murine models as well as in a small cohort of sensitized transplant recipients. In the present study, we aimed to determine the frequency of pre-existing and anti-HLA IgE antibodies in a cohort of 105 solid organ transplant recipients.
METHODS
We prospectively measured anti-HLA IgE antibodies in a cohort of kidney (n=60), liver, heart and lung (n=15 each) transplant recipients before and within one-year after transplantation, employing a single-antigen bead assay for HLA class I and class II antigens. Functional activity of anti-HLA IgE antibodies was assessed by an mediator release assay. Antibodies of the IgG1-4 subclasses and Th1 and Th2 cytokines were measured in anti-HLA IgE positive patients.
RESULTS
Pre-existing anti-HLA IgE antibodies were detected in 10% of renal recipients (including 3.3% IgE-DSA) and in 4.4% of non-renal solid organ transplant recipients (heart, liver and lung cohort). Anti-HLA IgE occurred only in patients that were positive for anti-HLA IgG, and most IgE positive patients had had a previous transplant. Only a small fraction of patients developed anti-HLA IgE antibodies (1.7% of kidney recipients and 4.4% of non-renal recipients), whereas no IgE-DSA was detected. IgG subclass antibodies showed a distinct pattern in patients who were positive for anti-HLA IgE. Moreover, patients with anti-HLA IgE showed elevated Th2 and also Th1 cytokine levels. Serum from IgE positive recipients led to degranulation of basophils , demonstrating functionality of anti-HLA IgE.
DISCUSSION
These data demonstrate that anti-HLA IgE antibodies occur at low frequency in kidney, liver, heart and lung transplant recipients. Anti-HLA IgE development is associated with sensitization at the IgG level, in particular through previous transplants and distinct IgG subclasses. Taken together, HLA specific IgE sensitization is a new phenomenon in solid organ transplant recipients whose potential relevance for allograft injury requires further investigation.
Topics: Humans; Animals; Mice; Prospective Studies; Liver; Heart Transplantation; Kidney; Immunosuppressive Agents; Antilymphocyte Serum; Immunoglobulin G; Lung; Immunoglobulin E
PubMed: 37731514
DOI: 10.3389/fimmu.2023.1179036 -
Cell Reports. Medicine Mar 2024Inclusion of defined quantities of the two major surface proteins of influenza virus, hemagglutinin (HA) and neuraminidase (NA), could benefit seasonal influenza...
Inclusion of defined quantities of the two major surface proteins of influenza virus, hemagglutinin (HA) and neuraminidase (NA), could benefit seasonal influenza vaccines. Recombinant HA and NA multimeric proteins derived from three influenza serotypes, H1N1, H3N2, and type B, are surface displayed on nanoliposomes co-loaded with immunostimulatory adjuvants, generating "hexaplex" particles that are used to immunize mice. Protective immune responses to hexaplex liposomes involve functional antibody elicitation against each included antigen, comparable to vaccination with monovalent antigen particles. When compared to contemporary recombinant or adjuvanted influenza virus vaccines, hexaplex liposomes perform favorably in many areas, including antibody production, T cell activation, protection from lethal virus challenge, and protection following passive sera transfer. Based on these results, hexaplex liposomes warrant further investigation as an adjuvanted recombinant influenza vaccine formulation.
Topics: Mice; Animals; Humans; Influenza Vaccines; Hemagglutinins; Neuraminidase; Orthomyxoviridae Infections; Influenza A Virus, H1N1 Subtype; Influenza A Virus, H3N2 Subtype; Liposomes; Influenza, Human; Adjuvants, Immunologic; Vaccines, Synthetic
PubMed: 38401547
DOI: 10.1016/j.xcrm.2024.101433 -
Immunity, Inflammation and Disease Nov 2023The introduction of the diphtheria-tetanus-pertussis (DTP) vaccine into childhood immunization programs resulted in its widespread elimination in high-income countries.... (Review)
Review
INTRODUCTION
The introduction of the diphtheria-tetanus-pertussis (DTP) vaccine into childhood immunization programs resulted in its widespread elimination in high-income countries. However, Nigeria is currently experiencing an outbreak. The primary cause of diphtheria outbreaks and its high mortality rates in Nigeria was waning herd immunity due to low DTP coverage and a lack of diphtheria antitoxin (DAT), respectively. However, the underlying causes of Nigeria's low DTP coverage and DAT supply remain unknown.
METHOD
Relevant studies and reports included in our review were obtained by a search through Google Scholar, PubMed, and organization websites using the terms "Diphtheria-Pertussis-Tetanus vaccine OR Diphtheria antitoxin and Nigeria OR Diphtheria Outbreak." All articles considering diphtheria outbreaks, DTP vaccine, and DAT supply in Nigeria were considered without time restriction due to the paucity of data. We used the narrative synthesis approach to critically appraise, analyze, and draw inferences from the selected articles.
RESULTS
The main causes of low DTP coverage are insufficient supply, an inefficient cold chain system, and low uptake due to poor health literacy and negative sociocultural and religious beliefs, whereas the key barriers to DAT availability are insufficient production by pharmaceutical industries because of low demand and priority.
CONCLUSION
The underlying causes of Nigeria's low DTP coverage and DAT supply are multifactorial. Both short-term and long-term measures are needed to control this outbreak and prevent future occurrences.
Topics: Humans; Child; Diphtheria; Diphtheria Antitoxin; Nigeria; Diphtheria-Tetanus-Pertussis Vaccine; Corynebacterium; Disease Outbreaks
PubMed: 38018582
DOI: 10.1002/iid3.1096 -
Journal of Leukocyte Biology Sep 2023Our objective was to characterize T and B cell responses to vaccination with SARS-CoV-2 antigens in immunocompromised rheumatoid arthritis (RA) patients. In 22 RA...
Our objective was to characterize T and B cell responses to vaccination with SARS-CoV-2 antigens in immunocompromised rheumatoid arthritis (RA) patients. In 22 RA patients, clinical and biological variables were analyzed before and 4 weeks after each of 3 messenger RNA (mRNA) vaccine doses and compared with unmatched healthy individuals. Sequentially sampled peripheral blood mononuclear cells and sera were collected to determine immune profiles and to analyze the T cell response to a spike peptide pool and B cell specificity to the receptor-binding domain (RBD). Anti-spike antibodies were detectable in 6 of 22 RA patients after 1 dose of vaccine with increasing titers after each booster dose, although the overall response was lower compared with that in healthy control individuals. Responding patients after the first dose were more likely to have RA antibodies and a higher baseline proportion of circulating follicular B cells. In RA patients, the mRNA vaccine elicited a robust CD4+ T response to a spike peptide pool following the first and second doses. Consistent with the serologies, RBD-specific B cells exhibited a modest increase after the first dose and the second dose resulted in marked increases only in a fraction of the RA patients to both ancestral and omicron RBD. Our results highlight the importance of multidose COVID-19 vaccination in RA patients to develop a protective humoral response. However, these patients rapidly develop specific T CD4+ responses, despite delayed B cell responses.
Topics: Humans; COVID-19 Vaccines; SARS-CoV-2; Leukocytes, Mononuclear; COVID-19; Arthritis, Rheumatoid; RNA, Messenger; Immunity; Antibodies, Viral; Vaccination; mRNA Vaccines
PubMed: 37478373
DOI: 10.1093/jleuko/qiad086