Microbial mimics supersize the pathogenic self-response.

Microbial mimicry, the process in which a microbial antigen elicits an immune response and breaks tolerance to a structurally related self-antigen, has long been proposed as a mechanism in autoimmunity. In this issue of the JCI, Dolton et al. extend this paradigm by demonstrating that a naturally processed peptide from Klebsiella oxytoca acts as a superagonist for autoreactive T cells in type 1 diabetes (T1D). Reframing microbial mimics as superagonists that are thousands of times better at binding disease-associated autoreactive T cell receptors than self-peptides serves to narrow the search space for relevant sequences in the vast microbial proteome. Moreover, the identified superagonists have implications for the intervention and personalized monitoring of T1D that may carry over to other autoimmune diseases with microbial mimicry.

Molecular Mimicry between Toxoplasma gondii B-Cell Epitopes and Neurodevelopmental Proteins: An Immunoinformatic Approach.

Epidemiological studies and meta-analyses have shown a strong association between high seroprevalence of Toxoplasma gondii (T. gondii) and schizophrenia. Schizophrenic patients showed higher levels of anti-Toxoplasma immunoglobulins M and G (IgM and IgG) when compared to healthy controls. Previously, in a rat model, we demonstrated that the progeny of mothers immunized with T. gondii lysates before gestation had behavioral and social impairments during adulthood. Therefore, we suggested that T. gondii infection can trigger autoreactivity by molecularly mimicking host brain proteins. Here, we aimed to identify the occurrence of antigenic mimicry between T. gondii epitopes and host brain proteins. Using a bioinformatic approach, we predicted T. gondii RH-88 B cell epitopes and compared them to human cell-surface proteins involved in brain development and differentiation (BrainS). Five different algorithms for B-cell-epitope prediction were used and compared, resulting in 8584 T. gondii epitopes. We then compared T. gondii predicted epitopes to BrainS proteins by local sequence alignments using BLASTP. T. gondii immunogenic epitopes significantly overlapped with 42 BrainS proteins. Among these overlapping proteins essential for brain development and differentiation, we identified HSP90 and NOTCH receptors as the proteins most likely to be targeted by the maternally generated pathogenic antibodies due to their topological overlap at the extracellular region of their sequence. This analysis highlights the relevance of pregestational clinical surveillance and screening for potential pathogenic anti-T. gondii antibodies. It also identifies potential targets for the design of vaccines that could prevent behavioral and cognitive impairments associated with pre-gestational T. gondii exposure.

Immune thrombocytopenia (ITP) - could it be part of autoimmune/inflammatory syndrome induced by adjuvants (ASIA)?

Immune thrombocytopenia (ITP) is a complex autoimmune disorder characterized by thrombocytopenia and an increased bleeding risk, arising from autoantibody-mediated platelet destruction and impaired megakaryocyte function. The pathogenesis of ITP involves a multifaceted interplay of genetic predispositions, immune dysregulation, and environmental triggers, though the precise mechanisms remain uncertain. Several infectious agents, mostly viruses, have been implicated in both acute and chronic ITP through mechanisms such as molecular mimicry, direct bone marrow suppression, and immune dysregulation. Vaccinations, particularly those containing adjuvants like aluminum and those capable of inducing molecular mimicry, have also been associated with ITP, either as a new onset or as a relapse in preexisting cases. The role of drugs, particularly quinine, quinidine and certain antibiotics, in inducing ITP through various immunological pathways further illustrates the diverse etiologies of this condition. The multiple triggers of the disease raise the question of whether ITP may be classified as an autoimmune/inflammatory syndrome induced by adjuvants (ASIA). This condition encompasses a range of autoimmune and inflammatory symptoms triggered by adjuvants, such as silicones, polypropylene meshes, metal implants, and mineral oils present in various medical materials and medications. Similar to that observed in some cases of ITP, adjuvants can trigger autoimmune or autoinflammatory responses via molecular mimicry, epitope spreading, and polyclonal activation. This narrative review explores the underlying environmental factors related to ITP and examines ITP triggers that could potentially support an association between ITP and ASIA syndrome.

Molecular mimicry in multisystem inflammatory syndrome in children.

Multisystem inflammatory syndrome in children (MIS-C) is a severe, post-infectious sequela of SARS-CoV-2 infection1,2, yet the pathophysiological mechanism connecting the infection to the broad inflammatory syndrome remains unknown. Here we leveraged a large set of samples from patients with MIS-C to identify a distinct set of host proteins targeted by patient autoantibodies including a particular autoreactive epitope within SNX8, a protein involved in regulating an antiviral pathway associated with MIS-C pathogenesis. In parallel, we also probed antibody responses from patients with MIS-C to the complete SARS-CoV-2 proteome and found enriched reactivity against a distinct domain of the SARS-CoV-2 nucleocapsid protein. The immunogenic regions of the viral nucleocapsid and host SNX8 proteins bear remarkable sequence similarity. Consequently, we found that many children with anti-SNX8 autoantibodies also have cross-reactive T cells engaging both the SNX8 and the SARS-CoV-2 nucleocapsid protein epitopes. Together, these findings suggest that patients with MIS-C develop a characteristic immune response to the SARS-CoV-2 nucleocapsid protein that is associated with cross-reactivity to the self-protein SNX8, demonstrating a mechanistic link between the infection and the inflammatory syndrome, with implications for better understanding a range of post-infectious autoinflammatory diseases.

Beyond glycan barriers: non-cognate ligands and protein mimicry approaches to elicit broadly neutralizing antibodies for HIV-1.

Human immunodeficiency virus type 1 (HIV-1) vaccine immunogens capable of inducing broadly neutralizing antibodies (bNAbs) remain obscure. HIV-1 evades immune responses through enormous diversity and hides its conserved vulnerable epitopes on the envelope glycoprotein (Env) by displaying an extensive immunodominant glycan shield. In elite HIV-1 viremic controllers, glycan-dependent bNAbs targeting conserved Env epitopes have been isolated and are utilized as vaccine design templates. However, immunological tolerance mechanisms limit the development of these antibodies in the general population. The well characterized bNAbs monoclonal variants frequently exhibit extensive levels of somatic hypermutation, a long third heavy chain complementary determining region, or a short third light chain complementarity determining region, and some exhibit poly-reactivity to autoantigens. This review elaborates on the obstacles to engaging and manipulating the Env glycoprotein as an effective immunogen and describes an alternative reverse vaccinology approach to develop a novel category of bNAb-epitope-derived non-cognate immunogens for HIV-1 vaccine design.

Harnessing microbial antigens as cancer antigens: a promising avenue for cancer immunotherapy.

Immunotherapy has revolutionized cancer treatment by leveraging the immune system's innate capabilities to combat malignancies. Despite the promise of tumor antigens in stimulating anti-tumor immune responses, their clinical utility is hampered by limitations in eliciting robust and durable immune reactions, exacerbated by tumor heterogeneity and immune evasion mechanisms. Recent insights into the immunogenic properties of host homologous microbial antigens have sparked interest in their potential for augmenting anti-tumor immunity while minimizing off-target effects. This review explores the therapeutic potential of microbial antigen peptides in tumor immunotherapy, beginning with an overview of tumor antigens and their challenges in clinical translation. We further explore the intricate relationship between microorganisms and tumor development, elucidating the concept of molecular mimicry and its implications for immune recognition of tumor-associated antigens. Finally, we discuss methodologies for identifying and characterizing microbial antigen peptides, highlighting their immunogenicity and prospects for therapeutic application.

HLA-A02 restricted T-cell cross-reactivity to a microbial antigen.

Molecular mimicry has been proposed to be a possible mechanism of induction of autoimmunity. In some cases, it is believed that such events could lead to a disease such as Type 1 diabetes (T1D). One of the primary MHC-I epitopes in the non-obese diabetic (NOD) mouse model of T1D has been identified as a peptide from the islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP) protein. In humans, the most common MHC-I model allele is HLA-A02; based on this, the study here identified a potential HLA-A0201-restricted human IGRP epitope as YLKTNLFLFL and also found a homologous A0201-restricted peptide in an Enterococcal protein. Using cells obtained from healthy human donors, it was seen that after a 2-week incubation with the synthetic bacterial protein, healthy A0201+ donor CD8+ cells displayed increased staining for human IGRP-peptide-dextramer. On the other hand, in control cultures, no significant levels of dextramer-staining CD8+ T-cells were detectable. From these outcomes, it is possible to conclude that certain bacterial proteins may initiate CD8+ T-cell-mediated immune reaction toward homologous human antigens.

Unveiling the intricacies of COVID-19: Autoimmunity, multi-organ manifestations and the role of autoantibodies.

COVID-19 is a severe infectious disease caused by a SARS-CoV-2 infection. It has caused a global pandemic and can lead to acute respiratory distress syndrome (ARDS). Beyond the respiratory system, the disease manifests in multiple organs, producing a spectrum of clinical symptoms. A pivotal factor in the disease's progression is autoimmunity, which intensifies its severity and contributes to multi-organ injuries. The intricate interaction between the virus' spike protein and human proteins may engender the generation of autoreactive antibodies through molecular mimicry. This can further convolute the immune response, with the potential to escalate into overt autoimmunity. There is also emerging evidence to suggest that COVID-19 vaccinations might elicit analogous autoimmune responses. Advanced technologies have pinpointed self-reactive antibodies that target diverse organs or immune-modulatory proteins. The interplay between autoantibody levels and multi-organ manifestations underscores the importance of regular monitoring of serum antibodies and proinflammatory markers. A combination of immunosuppressive treatments and antiviral therapy is crucial for managing COVID-19-associated autoimmune diseases. The review will focus on the generation of autoantibodies in the context of COVID-19 and their impact on organ health.

Molecular mimicry of SARS-COV-2 antigens as a possible natural anti-cancer preventive immunization.

Background: In the present study we investigated whether peptides derived from the entire SARS-CoV-2 proteome share homology to TAAs (tumor-associated antigens) and cross-reactive CD8+ T cell can be elicited by the BNT162b2 preventive vaccine or the SARS-CoV-2 natural infection. Methods and results: Viral epitopes with high affinity (<100nM) to the HLA-A*02:01 allele were predicted. Shared and variant-specific epitopes were identified. Significant homologies in amino acidic sequence have been found between SARS-CoV-2 peptides and multiple TAAs, mainly associated with breast, liver, melanoma and colon cancers. The molecular mimicry of the viral epitopes and the TAAs was found in all viral proteins, mostly the Orf 1ab and the Spike, which is included in the BNT162b2 vaccine. Predicted structural similarities confirmed the sequence homology and comparable patterns of contact with both HLA and TCR α and ß chains were observed. CD8+ T cell clones cross-reactive with the paired peptides have been found by MHC class l-dextramer staining. Conclusions: Our results show for the first time that several SARS-COV-2 antigens are highly homologous to TAAs and cross-reactive T cells are identified in infected and BNT162b2 preventive vaccinated individuals. The implication would be that the SARS-Cov-2 pandemic could represent a natural preventive immunization for breast, liver, melanoma and colon cancers. In the coming years, real-world evidences will provide the final proof for such immunological experimental evidence. Moreover, such SARS-CoV-2 epitopes can be used to develop "multi-cancer" off-the-shelf preventive/therapeutic vaccine formulations, with higher antigenicity and immunogenicity than over-expressed tumor self-antigens, for the potential valuable benefit of thousands of cancer patients around the World.

Interplay between the Chaperone System and Gut Microbiota Dysbiosis in Systemic Lupus Erythematosus Pathogenesis: Is Molecular Mimicry the Missing Link between Those Two Factors?

Systemic lupus erythematosus (SLE) is a multifactorial autoimmune disease characterized by self-immune tolerance breakdown and the production of autoantibodies, causing the deposition of immune complexes and triggering inflammation and immune-mediated damage. SLE pathogenesis involves genetic predisposition and a combination of environmental factors. Clinical manifestations are variable, making an early diagnosis challenging. Heat shock proteins (Hsps), belonging to the chaperone system, interact with the immune system, acting as pro-inflammatory factors, autoantigens, as well as immune tolerance promoters. Increased levels of some Hsps and the production of autoantibodies against them are correlated with SLE onset and progression. The production of these autoantibodies has been attributed to molecular mimicry, occurring upon viral and bacterial infections, since they are evolutionary highly conserved. Gut microbiota dysbiosis has been associated with the occurrence and severity of SLE. Numerous findings suggest that proteins and metabolites of commensal bacteria can mimic autoantigens, inducing autoimmunity, because of molecular mimicry. Here, we propose that shared epitopes between human Hsps and those of gut commensal bacteria cause the production of anti-Hsp autoantibodies that cross-react with human molecules, contributing to SLE pathogenesis. Thus, the involvement of the chaperone system, gut microbiota dysbiosis, and molecular mimicry in SLE ought to be coordinately studied.

Identification and characterization of a nonbiological small-molecular mimic of a Zika virus conformational neutralizing epitope.

Antigenic similarities between Zika virus (ZIKV) and other flaviviruses pose challenges to the development of virus-specific diagnostic tools and effective vaccines. Starting with a DNA-encoded one-bead-one-compound combinatorial library of 508,032 synthetic, non-natural oligomers, we selected and characterized small molecules that mimic ZIKV epitopes. High-throughput fluorescence-activated cell sorter-based bead screening was used to select molecules that bound IgG from ZIKV-immune but not from dengue-immune sera. Deep sequencing of the DNA from the "Zika-only" beads identified 40 candidate molecular structures. A lead candidate small molecule "CZV1-1" was selected that correctly identifies serum specimens from Zika-experienced patients with good sensitivity and specificity (85.3% and 98.4%, respectively). Binding competition studies of purified anti-CZV1-1 IgG against known ZIKV-specific monoclonal antibodies (mAbs) showed that CZV1-1 mimics a nonlinear, neutralizing conformational epitope in the domain III of the ZIKV envelope. Purified anti-CZV1-1 IgG neutralized infection of ZIKV in cell cultures with potencies comparable to highly specific ZIKV-neutralizing mAbs. This study demonstrates an innovative approach for identification of synthetic non-natural molecular mimics of conformational virus epitopes. Such molecular mimics may have value in the development of accurate diagnostic assays for Zika, as well as for other viruses.

[In Silico analysis of molecular mimic between Der p 23 against allergenic sources]. / Análisis in silico del mimetismo molecular entre Der p 23 contra fuentes alergénicas.

OBJECTIVE: To identify through In Silico analysis the possible molecular mimicry between Der p 23 and antigens from allergenic sources. METHODS: Identity was sought between Der p 23 and proteins from the mite families Pyroglyphidae, Acaridae, Chortoglyphidae and Echimyopodidae, through PSI-BLAST and They used PRALINE and EMBOSS for the alignments. Antigens with resolved experimental structure were obtained from Protein Data Bank and those not reported were generated using Swiss Model server and ALPHAFOLD 2. Epitope prediction was carried out with the Ellipro server and Pymol 2.3 was used to visualize the 3D models. RESULTS: The analysis between Pyroglyphidae allergens and Der p 23 showed identity with the endochitinase-like protein of D. pteronyssinus, and the type 2 chitin binding domain of D. farinae, with identities between 85 and 100%, with coverage of 100%, and 75% respectively. The allergens Der f 23 and Der p 23 of D. farinae and D. pteronyssinus had 100% coverage with identities of 85.42% and 79.59%, respectively. Among the allergens of Tyrophagus putrescentiae, binding to chitin, oviduct-specific glycoprotein and Cda4p were included, which had identity values corresponding to 40%, 42.22% and 34.78%, with coverage values that did not exceed the 55%. No results were found for Chortoglyphidae and Echimyopodidae. CONCLUSION: There is molecular mimicry and structural homology between Der P 23 and allergens from allergic sources of the Pyroglyphidae and Acaridae families. Potential epitopes were identified in Der p 23, which could present cross-reactivity with the proteins of the allergenic sources studied, which must be demonstrated in In vitro and In vivo studies. In vitro and in vivo work is needed to demonstrate the results obtained in the In Silico analysis.

OBJETIVO: Identificar, a través de análisis In Silico, el posible mimetismo molecular entre Der p 23 y antígenos de fuentes alergénicas. MÉTODOS: Se buscó identidad entre Der p 23 y proteínas de las familias de ácaros Pyroglyphidae, Acaridae, Chortoglyphidae y Echimyopodidae, a través de PSI-BLAST, y se utilizaron PRALINE y EMBOSS para los alineamientos. Los antígenos con estructura experimental resuelta se obtuvieron de Protein Data Bank, y aquellos no informados, se generaron mediante Swiss Model Server y ALPHAFOLD 2. La predicción de epítopes se realizó con el servidor Ellipro y para la visualización de los modelos en 3D, se utilizó Pymol 2.3. RESULTADOS: El análisis entre alérgenos de Pyroglyphidae y Der p 23, mostró identidad con la proteína parecida a endoquitinasa de D. pteronyssinus, y el dominio de unión a quitina tipo 2 de D. farinae, con identidades entre 85 y 100%, con coberturas de 100% y 75%, respectivamente. Los alérgenos Der f 23 y Der p 23 de D. farinae y D. pteronyssinu,s tuvieron una cobertura del 100% con identidades del 85,42% y 79,59%, respectivamente. Entre los alérgenos de Tyrophagus putrescentiae, se incluyeron la unión a quitina, glicoproteína específica del oviducto y Cda4p, las cuales tuvieron valores de identidad correspondientes al 40%, 42,22% y 34,78%, con valores de cobertura que no superan el 55%. No se encontraron resultados para Chortoglyphidae y Echimyopodidae. CONCLUSIÓN: Existe mimetismo molecular y homología estructural entre Der P 23 y alérgenos de fuentes alérgicas de las familias Pyroglyphidae y Acaridae. Se identificaron potenciales epítopes en Der p 23, los cuales podrían presentar reactividad cruzada con las proteínas de las fuentes alergénicas estudiadas, lo cual debe ser demostrado en estudios In Vitro e In Vivo. Se necesitan trabajos In Vitro e In Vivo que demuestren los resultados obtenidos en el análisis In Silico.

[Molecular mimicry between Plasmodium sp and Guillain-Barre syndrome antigens]. / Mimetismo molecular entre el Plasmodium sp y los antígenos del síndrome de Guillain-Barre.

OBJECTIVE: Analyze the molecular mimicry between Plasmodium spp. and autoantigens associated with GBS, identifying possible antigenic epitopes. METHODS: PSI-Blast, Praline, Emboss, Protein Data Bank, Swiss Model Server, AlphaFold 2, Ellipro and PyMol 2.3 were used to search for homologies, perform alignments, obtain protein structures, and predict epitopes. RESULTS: 17 autoantigens and seven immunological targets of the peripheral nervous system were included, identifying 72 possible epitopes associated with GBS. From the proteome of Plasmodium spp. (298 proteins), only two showed similarities close to 30% with TRIM21 and BACE1, generating seven possible epitopes. CONCLUSION: No significant homologies were observed between the proteome of GBS and Plasmodium spp. The exploration of other mechanisms such as immune-mediated capillary damage, Epitope Spreading or Bystander Activation is suggested to explain the mentioned association. These findings underscore the need to clarify the etiology of autoimmune diseases and the role of pathogens. The need for experimental studies to validate these results is emphasized.

OBJETIVO: Analizar el mimetismo molecular entre Plasmodium spp. y autoantígenos asociados al SGB, identificando posibles epítopos antigénicos. MÉTODOS: Se emplearon PSI-Blast, Praline, Emboss, Protein Data Bank, Swiss Model Server, AlphaFold 2, Ellipro y PyMol 2.3 para buscar homologías, realizar alineamientos, obtener estructuras proteicas y predecir epítopos. RESULTADOS: Se incluyeron 17 autoantígenos y siete objetivos inmunológicos del sistema nervioso periférico, identificándose 72 posibles epítopos asociados al SGB. Del proteoma de Plasmodium spp. (298 proteínas), solo dos mostraron similitud cercana al 30% con TRIM21 y BACE1, generando siete posibles epítopos. CONCLUSIÓN: No se observaron homologías significativas entre el proteoma de SGB y Plasmodium spp. Se sugiere la exploración de otros mecanismos como el daño capilar inmunomediado, Epitope Spreading o Bystander Activation para explicar la asociación mencionada. Estos hallazgos subrayan la necesidad de aclarar la etiología de las enfermedades autoinmunes y el papel de los patógenos. Se enfatiza la necesidad de estudios experimentales para validar estos resultados.

[Molecular mimic between cardiovascular diseases and microorganism antigens]. / Mimetismo molecular entre enfermedades cardiovasculares y antígenos de microorganismos.

INTRODUCTION: Cardiovascular diseases are the result of genetic and environmental interaction that conditions the integrity of the heart and blood vessels. Risk factors include infections. The inflammatory response against the infectious agent is a trigger of autoimmune cardiovascular diseases due to the similarity between the pathogen proteins and human antigens, since the immune response can present cross-reactivity caused by molecular mimicry. METHODS: We performed a search for pathogens involved in autoimmune heart diseases and autoantigens 9 associated with these diseases in the Pubmed and Google Scholar search engines. Identity between proteins was performed through global alignments using PSI-BLAST. The 3D structures of the proteins were obtained by Uniprot or NCBI and, if not found, the structure was modeled by homology using the Swiss Model server. Epitope prediction was performed through Ellipro and the Immunological Epitope Database (IEDB). In addition, the PYMOL program was used to visualize proteins in 3D and position the epitopes in the structure. RESULTS: A total of ten cardiovascular proteins showed identity (30-88,24%) in their amino acid sequences with antigens from 10 pathogens. Actin proteins and heat shock protein (HSP) families had higher levels of identity with Trypanosoma Cruzi, Cryptococcus neoformans, and Chlamydia trachomatis, 71,47%, 88,24%, and 80,61%, respectively. Other pathogens, such as Streptococcus pyogenes, Bacillus sp, Magnetospirillum gryphiswaldense, Helicobacter pylori and Chlamydia pneumoniae, presented a moderate identity with a maximum value of 65,79%. CONCLUSION: Human actin and HSPs share a high degree of conservation with epitopes from various microorganisms, such as bacteria, fungi and protozoa, suggesting molecular mimicry and cross-reactivity as a mechanism for the development of atherosclerosis, heart disease rheumatic disease, myocarditis and Chagas heart disease. In vitro and in vivo work is needed to demonstrate the results obtained in the In Silico analysis.

INTRODUCCIÓN: Las enfermedades cardiovasculares son el resultado de la interacción genética y ambiental que condiciona la integridad del corazón y los vasos sanguíneos. Los factores de riesgo incluyen infecciones. La respuesta inflamatoria contra el agente infeccioso es un desencadenante de las enfermedades cardiovasculares autoinmunes, debido a la similitud entre las proteínas del patógeno y los antígenos humanos, pues la respuesta inmunitaria puede presentar reactividad cruzada causada por mimetismo molecular. MÉTODOS: Realizamos una búsqueda de patógenos involucrados en enfermedades cardíacas autoinmunes y de autoantígenos asociados a estas enfermedades en los buscadores Pubmed y Google Scholar. La identidad entre proteínas se realizó a través de alineamientos globales utilizando PSI-BLAST. Las estructuras 3D de las proteínas fue obtenida por Uniprot o NCBI y, si no se encontraban, las estructuras se modelaban por homología, utilizando el servidor Swiss Model. La predicción de los epítopes se realizó a través de Ellipro, y la Base de Datos de Epítopos Inmunológicos (IEDB). Además, se utilizó el programa PYMOL para la visualización de proteínas en 3D, y el posicionamiento de los epítopes en la estructura. RESULTADOS: Diez proteínas cardiovasculares mostraron una identidad (30-88,24%) en sus secuencias de aminoácidos con antígenos de diez patógenos. Las proteínas de actina y las familias de proteínas de choque térmico (HSP, por sus siglas en inglés), presentaron niveles de identidad más altos con Trypanosoma Cruzi, Cryptococcus neoformans y Chlamydia trachomatis, 71,47%, 88,24% y 80,61%, respectivamente. Otros patógenos, como Streptococcus pyogenes, Bacillus sp, Magnetospirillum gryphiswaldense, Helicobacter pylori y Chlamydia pneumoniae, presentaron identidad moderada con un valor máximo del 65,79%. CONCLUSIÓN: La actina humana y las HSP comparten un alto grado de conservación con epítopos de varios microorganismos, como bacterias, hongos y protozoos; lo que sugiere la imitación molecular y la reactividad cruzada como mecanismos para el desarrollo de la aterosclerosis, la enfermedad cardíaca reumática, la miocarditis y la enfermedad cardíaca de Chagas. Se necesitan trabajos in vitro e in vivo, que demuestren los resultados obtenidos en el análisis In Silico.

[Molecular mimicry between human thyroid peroxidase, thyroglobulin, cosinophil peroxidase, IL-24 and microorganisms antigens]. / Mimetismo molecular entre peroxidasa tiroidea humana, tiroglobulina, peroxidasa de eosinófilos, IL-24 y antígenos de microorganismos.

OBJECTIVE: Identify molecular mimicry between TPO, eosinophil peroxidase (EPX), thyroglobulin and IL24 and microorganism antigens. METHODS: Through in silico analysis, we performed local alignments between human and microorganism antigens with PSI-BLAST. Proteins that did not present a 3D structure were modeled by homology through the Swiss Modeller server and epitope prediction was performed through Ellipro. Epitopes were located in the 3D models using PYMOL software. RESULTS: A total of 38 microorganism antigens (parasites, bacteria) had identities between 30% and 45%, being the highest with Anisakis simplex. The alignment between 2 candidate proteins from A. simplex and EPX presented significant values, with identities of 43 and 44%. In bacteria, Campylobacter jejuni presented the highest identity with thyroglobulin (35%). 220 linear and conformational epitopes of microorganism antigens were predicted. Peroxidasin-like proteins from Toxocara canis and Trichinella pseudospiralis presented 10 epitopes similar to TPO and EPX, as possible molecules triggering cross-reactivity. No virus presented identity with the human proteins studied. CONCLUSION: TPO and EPX antigens shared potential cross-reactive epitopes with bacterial and nematode proteins, suggesting that molecular mimicry could be a mechanism that explains the relationship between infections and urticaria/hypothyroidism. In vitro work is needed to demonstrate the results obtained in the in silico analysis.

OBJETIVO: Identificar mimetismo molecular entre TPO, eosinofil peroxidasa (EPX), tiroglobulina e IL24 y antígenos de microorganismos. MÉTODOS: A través de análisis in silico, realizamos los alineamientos locales entre los antígenos humanos y de microorganismos con PSI-BLAST. Las proteínas que no presentaban estructura 3D, fueron modeladas por homología a través del servidor Swiss Modeller y se realizó una predicción de epítopes a través de Ellipro. Los epítopes se localizaron en los modelos 3D utilizando el software PYMOL. RESULTADOS: Un total de 38 antígenos de microorganismos (parásitos y bacterias), tuvieron identidades entre 30 y 45%, siendo los más altos con Anisakis simplex. El alineamiento entre dos proteínas candidatas de A. simplex y EPX presentaron valores importantes, con identidades de 43 y 44%. En las bacterias, Campylobacter jejuni presentó la mayor identidad con tiroglobulina (35%). Se predijeron 220 epítopes lineales y conformacionales de antígenos de microorganismos. Las proteínas similares a la peroxidasina de Toxocara canis y Trichinella pseudospiralis presentaron diez epítopes similares a TPO y EPX, como posibles moléculas desencadenantes de una reactividad cruzada. Ningún virus presentó identidad con las proteínas humanas estudiadas. CONCLUSIÓN: Los antígenos TPO y EPX compartieron potenciales epítopes de reacción cruzada con proteínas bacterianas y nematodos, lo que sugiere que el mimetismo molecular podría ser un mecanismo que explique la relación entre infecciones y la urticaria/hipotiroidismo. Se necesitan trabajos in vitro que demuestren los resultados obtenidos en el análisis in silico.

Antigen mimicry as an effective strategy to induce CSPG4-targeted immunity in dogs with oral melanoma: a veterinary trial.

BACKGROUND: Melanoma is the most lethal form of skin cancer in humans. Conventional therapies have limited efficacy, and overall response is still unsatisfactory considering that immune checkpoint inhibitors induce lasting clinical responses only in a low percentage of patients. This has prompted us to develop a vaccination strategy employing the tumor antigen chondroitin sulfate proteoglycan (CSPG)4 as a target. METHODS: To overcome the host's unresponsiveness to the self-antigen CSPG4, we have taken advantage of the conservation of CSPG4 sequence through phylogenetic evolution, so we have used a vaccine, based on a chimeric DNA molecule encompassing both human (Hu) and dog (Do) portions of CSPG4 (HuDo-CSPG4). We have tested its safety and immunogenicity (primary objectives), along with its therapeutic efficacy (secondary outcome), in a prospective, non-randomized, veterinary clinical trial enrolling 80 client-owned dogs with surgically resected, CSPG4-positive, stage II-IV oral melanoma. RESULTS: Vaccinated dogs developed anti-Do-CSPG4 and Hu-CSPG4 immune response. Interestingly, the antibody titer in vaccinated dogs was significantly associated with the overall survival. Our data suggest that there may be a contribution of the HuDo-CSPG4 vaccination to the improvement of survival of vaccinated dogs as compared with controls treated with conventional therapies alone. CONCLUSIONS: HuDo-CSPG4 adjuvant vaccination was safe and immunogenic in dogs with oral melanoma, with potential beneficial effects on the course of the disease. Thanks to the power of naturally occurring canine tumors as predictive models for cancer immunotherapy response, these data may represent a basis for the translation of this approach to the treatment of human patients with CSPG4-positive melanoma subtypes.

Mouse Models of Antigen Presentation in Hematopoietic Stem Cell Transplantation.

Allogeneic stem cell transplantation (alloSCT) is a curative therapy for hematopoietic malignancies. The therapeutic effect relies on donor T cells and NK cells to recognize and eliminate malignant cells, known as the graft-versus-leukemia (GVL) effect. However, off target immune pathology, known as graft-versus-host disease (GVHD) remains a major complication of alloSCT that limits the broad application of this therapy. The presentation of recipient-origin alloantigen to donor T cells is the primary process initiating GVHD and GVL. Therefore, the understanding of spatial and temporal characteristics of alloantigen presentation is pivotal to attempts to separate beneficial GVL effects from detrimental GVHD. In this review, we discuss mouse models and the tools therein, that permit the quantification of alloantigen presentation after alloSCT.

Autoimmune hepatitis after COVID-19 vaccine - more than a coincidence.

The COVID-19 pandemic is still raging across the world and vaccination is expected to lead us out of this pandemic. Although the efficacy of the vaccines is beyond doubt, safety still remains a concern. We report a case of a 65-year-old woman who experienced acute severe autoimmune hepatitis two weeks after receiving the first dose of Moderna-COVID-19 vaccine. Serum immunoglobulin G was elevated and antinuclear antibody was positive (1:100, speckled pattern). Liver histology showed a marked expansion of the portal tracts, severe interface hepatitis and multiple confluent foci of lobular necrosis. She started treatment with prednisolone, with a favorable clinical and analytical evolution. Some recent reports have been suggested that COVID-19 vaccination can lead to the development of autoimmune diseases. It is speculated that the vaccine can disturb self-tolerance and trigger autoimmune responses through cross-reactivity with host cells. Therefore, healthcare providers must remain vigilant during mass COVID-19 vaccination.

A case of Graves' disease and type 1 diabetes mellitus following SARS-CoV-2 vaccination.

Autoimmune diseases, including autoimmune endocrine diseases (AIED), are thought to develop following environmental exposure in patients with genetic predisposition. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and vaccines against it could represent new environmental triggers for AIED. We report a patient, with history of vitiligo vulgaris and 8 years of type 2 diabetes, who came to our institution because of fever, weight loss, asthenia and thyrotoxicosis occurred 4 weeks later the administration of BNT162B2 (Pfizer-BioNTech) SARS-CoV-2 vaccine. Clinical, biochemical and instrumental work-up demonstrated Graves' disease and autoimmune diabetes mellitus. The occurrence of these disorders could be explained through different mechanism such as autoimmune/inflammatory syndrome induced by adjuvants (ASIA syndrome), mRNA "self-adjuvant" effect, molecular mimicry between human and viral proteins and immune disruption from external stimuli. However further studies are needed to better understand the underlying pathogenesis of AIED following SARS-CoV-2 vaccine.