RESUMEN
Vaccines containing tetanus-diphtheria antigens have been postulated to induce cross-reactive immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which could protect against coronavirus disease (COVID-19). In this work, we investigated the capacity of Tetanus-diphtheria (Td) vaccine to prime existing T cell immunity to SARS-CoV-2. To that end, we first collected known SARS-CoV-2 specific CD8+ T cell epitopes targeted during the course of SARS-CoV-2 infection in humans and identified as potentially cross-reactive with Td vaccine those sharing similarity with tetanus-diphtheria vaccine antigens, as judged by Levenshtein edit distances (≤ 20% edits per epitope sequence). As a result, we selected 25 potentially cross-reactive SARS-CoV-2 specific CD8+ T cell epitopes with high population coverage that were assembled into a synthetic peptide pool (TDX pool). Using peripheral blood mononuclear cells, we first determined by intracellular IFNγ staining assays existing CD8+ T cell recall responses to the TDX pool and to other peptide pools, including overlapping peptide pools covering SARS-CoV-2 Spike protein and Nucleocapsid phosphoprotein (NP). In the studied subjects, CD8+ T cell recall responses to Spike and TDX peptide pools were dominant and comparable, while recall responses to NP peptide pool were less frequent and weaker. Subsequently, we studied responses to the same peptides using antigen-inexperienced naive T cells primed/stimulated in vitro with Td vaccine. Priming stimulations were carried out by co-culturing naive T cells with autologous irradiated peripheral mononuclear cells in the presence of Td vaccine, IL-2, IL-7 and IL-15. Interestingly, naive CD8+ T cells stimulated/primed with Td vaccine responded strongly and specifically to the TDX pool, not to other SARS-CoV-2 peptide pools. Finally, we show that Td-immunization of C57BL/6J mice elicited T cells cross-reactive with the TDX pool. Collectively, our findings support that tetanus-diphtheria vaccines can prime SARS-CoV-2 cross-reactive T cells and likely contribute to shape the T cell responses to the virus.
Asunto(s)
Linfocitos T CD8-positivos , COVID-19 , Reacciones Cruzadas , Epítopos de Linfocito T , SARS-CoV-2 , Humanos , Reacciones Cruzadas/inmunología , SARS-CoV-2/inmunología , Linfocitos T CD8-positivos/inmunología , Epítopos de Linfocito T/inmunología , COVID-19/inmunología , COVID-19/prevención & control , Toxoide Tetánico/inmunología , Animales , Ratones , Femenino , Vacunas contra la COVID-19/inmunología , Masculino , Adulto , Glicoproteína de la Espiga del Coronavirus/inmunología , Persona de Mediana EdadRESUMEN
Regulatory T cells (Tregs) control immune responses and are essential to maintain immune homeostasis and self-tolerance. Hence, it is no coincidence that autoimmune and chronic inflammatory disorders are associated with defects in Tregs. These diseases have currently no cure and are treated with palliative drugs such as immunosuppressant and immunomodulatory agents. Thereby, there is a great interest in developing medical interventions against these diseases based on enhancing Treg cell function and numbers. Here, we give an overview of Treg cell ontogeny and function, paying particular attention to mucosal Tregs. We review some notable approaches to enhance immunomodulation by Tregs with therapeutic purposes including adoptive Treg cell transfer therapy and discuss relevant clinical trials for inflammatory bowel disease. We next introduce ways to expand mucosal Tregs in vivo using microbiota and dietary products that have been the focus of clinical trials in various autoimmune and chronic-inflammatory diseases.
Asunto(s)
Enfermedades Autoinmunes , Linfocitos T Reguladores , Humanos , Enfermedades Autoinmunes/terapia , Tolerancia Inmunológica , Inmunoterapia Adoptiva , InmunomodulaciónRESUMEN
Vaccines are the most successful and cost-effective medical interventions available to fight infectious diseases. They consist of biological preparations that are capable of stimulating the immune system to confer protective immunity against a particular harmful pathogen/agent. Vaccine design and development have evolved through the years. Early vaccines were obtained with little implementation of technology and in the absence of fundamental knowledge, representing a pure feat of human ingenuity. In contrast, modern vaccine development takes advantage of advances in technology and in our enhanced understanding of the immune system and host-pathogen interactions. Moreover, vaccine design has found novel applications beyond the prophylactic arena and there is an increasing interest in designing vaccines to treat human ailments like cancer and chronic inflammatory diseases. In this chapter, we focus on prophylactic vaccines against infectious diseases, providing an overview on immunology principles underlying immunization and on how vaccines work and are designed.
Asunto(s)
Vacunas , Humanos , Adyuvantes Inmunológicos , Vacunación , Desarrollo de VacunasRESUMEN
Activation of the integrin phagocytic receptors CR3 (αMß2, CD11b/CD18) and CR4 (αXß2, CD11c/CD18) requires Rap1 activation and RIAM function. RIAM controls integrin activation by recruiting Talin to ß2 subunits, enabling the Talin-Vinculin interaction, which in term bridges integrins to the actin-cytoskeleton. RIAM also recruits VASP to phagocytic cups and facilitates VASP phosphorylation and function promoting particle internalization. Using a CRISPR-Cas9 knockout approach, we have analyzed the requirement for RIAM, VASP and Vinculin expression in neutrophilic-HL-60 cells. All knockout cells displayed abolished phagocytosis that was accompanied by a significant and specific reduction in ITGAM (αM), ITGAX (αX) and ITGB2 (ß2) mRNA, as revealed by RT-qPCR. RIAM, VASP and Vinculin KOs presented reduced cellular F-actin content that correlated with αM expression, as treatment with the actin filament polymerizing and stabilizing drug jasplakinolide, partially restored αM expression. In general, the expression of αX was less responsive to jasplakinolide treatment than αM, indicating that regulatory mechanisms independent of F-actin content may be involved. The Serum Response Factor (SRF) was investigated as the potential transcription factor controlling αMß2 expression, since its coactivator MRTF-A requires actin polymerization to induce transcription. Immunofluorescent MRTF-A localization in parental cells was primarily nuclear, while in knockouts it exhibited a diffuse cytoplasmic pattern. Localization of FHL-2 (SRF corepressor) was mainly sub-membranous in parental HL-60 cells, but in knockouts the localization was disperse in the cytoplasm and the nucleus, suggesting RIAM, VASP and Vinculin are required to maintain FHL-2 close to cytoplasmic membranes, reducing its nuclear localization and inhibiting its corepressor activity. Finally, reexpression of VASP in the VASP knockout resulted in a complete reversion of the phenotype, as knock-ins restored αM expression. Taken together, our results suggest that RIAM, VASP and Vinculin, are necessary for the correct expression of αMß2 and αXß2 during neutrophilic differentiation in the human promyelocytic HL-60 cell line, and strongly point to an involvement of these proteins in the acquisition of a phagocytic phenotype.
Asunto(s)
Actinas , Talina , Proteínas Adaptadoras Transductoras de Señales , Moléculas de Adhesión Celular , Proteínas Co-Represoras , Células HL-60 , Humanos , Integrina alfaXbeta2 , Integrinas/metabolismo , Antígeno de Macrófago-1 , Proteínas de la Membrana , Proteínas de Microfilamentos , Neutrófilos/metabolismo , Fosfoproteínas , ARN Mensajero , Factor de Respuesta Sérica , Talina/genética , Talina/metabolismo , Vinculina/genética , Vinculina/metabolismoRESUMEN
Human rhinovirus (RV) is the most common cause of upper respiratory infections and exacerbations of asthma. In this work, we selected 14 peptides (6 from RV A and 8 from RV C) encompassing potential CD4 T cell epitopes. Peptides were selected for being highly conserved in RV A and C serotypes and predicted to bind to multiple human leukocyte antigen class II (HLA II) molecules. We found positive T cell recall responses by interferon gamma (IFNγ)-ELISPOT assays to eight peptides, validating seven of them (three from RV A and four from RV C) as CD4 T cell epitopes through intracellular cytokine staining assays. Additionally, we verified their promiscuous binding to multiple HLA II molecules by quantitative binding assays. According to their experimental HLA II binding profile, the combination of all these seven epitopes could be recognized by >95% of the world population. We actually determined IFNγ responses to a pool encompassing these CD4 T cell epitopes by intracellular cytokine staining, finding positive responses in 29 out of 30 donors. The CD4 T cell epitopes identified in this study could be key to monitor RV infections and to develop peptide-based vaccines against most RV A and C serotypes.