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[This corrects the article DOI: 10.3389/fimmu.2023.1241038.].
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The SARS CoV-2 antibody and CD4+ T cell responses induced by natural infection and/or vaccination decline over time and cross-recognize other viral variants at different levels. However, there are few studies evaluating the levels and durability of the SARS CoV-2-specific antibody and CD4+ T cell response against the Mu, Gamma, and Delta variants. Here, we examined, in two ambispective cohorts of naturally-infected and/or vaccinated individuals, the titers of anti-RBD antibodies and the frequency of SARS-CoV-2-specific CD4+ T cells up to 6 months after the last antigen exposure. In naturally-infected individuals, the SARS-CoV-2 antibody response declined 6 months post-symptoms onset. However, the kinetic observed depended on the severity of the disease, since individuals who developed severe COVID-19 maintained the binding antibody titers. Also, there was detectable binding antibody cross-recognition for the Gamma, Mu, and Delta variants, but antibodies poorly neutralized Mu. COVID-19 vaccines induced an increase in antibody titers 15-30 days after receiving the second dose, but these levels decreased at 6 months. However, as expected, a third dose of the vaccine caused a rise in antibody titers. The dynamics of the antibody response upon vaccination depended on the previous SARS-CoV-2 exposure. Lower levels of vaccine-induced antibodies were associated with the development of breakthrough infections. Vaccination resulted in central memory spike-specific CD4+ T cell responses that cross-recognized peptides from the Gamma and Mu variants, and their duration also depended on previous SARS-CoV-2 exposure. In addition, we found cross-reactive CD4+ T cell responses in unexposed and unvaccinated individuals. These results have important implications for vaccine design for new SARS-CoV-2 variants of interest and concern.
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COVID-19 , SARS-CoV-2 , Humanos , Vacunas contra la COVID-19 , Colombia/epidemiología , Linfocitos T , Anticuerpos Antivirales , Linfocitos T CD4-PositivosRESUMEN
BACKGROUND: In humans, blood circulating IgM+IgD+CD27+ B cells are considered analogous to those described in the marginal zone of the spleen and are involved in important immunological processes. The homing receptors they express, and the organs involved in their development (for example, intestinal organs in rabbits) are only partially known. We recently reported that this population is heterogeneous and composed of at least two subsets: one expressing high levels of IgM - IgMhi B cells - and another low levels - IgMlo B cells. OBJECTIVES: To evaluate the expression of homing receptors on IgD+CD27+ IgMhi and IgMlo B cells and quantify their frequencies in blood of control and appendectomized and/or tonsillectomized volunteers. MATERIALS AND METHODS: Using spectral flow cytometry, the simultaneous expression of 12 previously reported markers that differentiate IgMhi B cells and IgMlo B cells and of α4ß7, CCR9, CD22 and CCR10 were evaluated in blood circulating B cells of control and appendectomized and/or tonsillectomized volunteers. RESULTS: The existence of phenotypically defined IgMlo and IgMhi B cell subsets was confirmed. They differentially expressed intestinal homing receptors, and the expression of α4ß7 and CCR9 seems to determine new IgM subpopulations. IgMlo and IgMhi B cells were detected at lower frequencies in the appendectomized and/or tonsillectomized volunteers relative to controls. CONCLUSIONS: Human blood circulating IgD+CD27+ IgMlo and IgMhi B cell subsets differentially express homing receptors, and it is necessary to investigate if mucosal organs are important in their development.
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Subgrupos de Linfocitos B , Linfocitos B , Animales , Humanos , Conejos , Inmunoglobulina M , Citometría de FlujoRESUMEN
This study aimed to determine the cumulative incidence, prevalence, and seroconversion of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and its associated factors among healthcare workers (HCWs) of a University Hospital in Bogotá, Colombia. An ambispective cohort was established from March 2020 to February 2021. From November 2020 to February 2021, SARS-CoV-2 antibodies were measured on two occasions 14-90 days apart to determine seroprevalence and seroconversion. We used multivariate log-binomial regression to evaluate factors associated with SARS-CoV-2 infection. Among 2,597 HCWs, the cumulative incidence of infection was 35.7%, and seroprevalence was 21.5%. A reduced risk of infection was observed among those aged 35-44 and ≥45 years (adjusted relative risks [aRRs], 0.84 and 0.83, respectively), physicians (aRR, 0.77), those wearing N95 respirators (aRR, 0.82) and working remotely (aRR, 0.74). Being overweight (aRR, 1.18) or obese (aRR, 1.24); being a nurse or nurse assistant (aRR, 1.20); working in the emergency room (aRR, 1.45), general wards (aRR, 1.45), intensive care unit (aRR, 1.34), or COVID-19 areas (aRR, 1.17); and close contact with COVID-19 cases (aRR, 1.47) increased the risk of infection. The incidence of SARS-CoV-2 infection found in this study reflects the dynamics of the first year of the pandemic in Bogotá. A high burden of infection calls for strengthening prevention and screening measures for HCWs, focusing especially on those at high risk.
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COVID-19 , COVID-19/epidemiología , Colombia/epidemiología , Personal de Salud , Hospitales Universitarios , Humanos , Incidencia , Prevalencia , SARS-CoV-2 , Seroconversión , Estudios SeroepidemiológicosRESUMEN
Abstract Objectives: To determine the prevalence of antibodies to SARS-CoV-2 and the incidence of seroconversion in the first month of follow-up among interns, residents, and medical doctors attending patients at a University Hospital in Bogota (Colombia). Design or methods: A cross-sectional and a prospective study were performed during June, July, and August 2020 to assess seroprevalence and seroconversion rates using CLIA IgG for SARS-CoV-2. LFA IgG and IgM and ELFA IgM were also determined to explore concordance with CLIA IgG. Results: At baseline, 8 (2.28% 95%CI 1.16-4.43%) participants were IgG positive for SARS-CoV-2 by CLIA. At the end of the study, 21 (5.98% 95%CI 3.94-8.97%) individuals seroconverted by CLIA IgG. In all, 29 individuals had IgG by CLIA and of these 11 (3.13% 95%CI 1.76-5.52%) were asymptomatic. No associations with risk factors for infection were identified. CLIA IgG had moderate concordance (>962 samples) with LFA IgG and ELFA IgM, but minimal with LFA IgM. Conclusions: Our report is the first in Latina America on seroprevalence and seroconversion rates in medical healthcare workers. The relatively high rate (>3%) of asymptomatic health care workers with evidence of previous SARS-CoV-2 infection underscores the need to screen this population for infection to prevent infection/disease spread.
Resumen Objetivos: Determinar la prevalencia de anticuerpos frente al SARS-CoV-2 y la incidencia de seroconversión en el primer mes de seguimiento en internos, residentes y médicos que atienden pacientes en un Hospital Universitario de Bogotá (Colombia). Diseño y métodos: Se realizó un estudio transversal y prospectivo durante junio, julio y agosto de 2020 para evaluar las tasas de seroprevalencia y seroconversión utilizando CLIA IgG para SARS-CoV-2. También se determinaron LFA IgG e IgM y ELFA IgM para explorar la concordancia con CLIA IgG. Resultados: Al inicio del estudio, 8 (2,28% IC del 95% 1,16-4,43%) participantes fueron IgG positivos para SARS-CoV-2 por CLIA. Al final del estudio, 21 (5,98% IC 95% 3,94-8,97%) individuos seroconvirtieron por CLIA IgG. En total, 29 individuos tenían IgG por CLIA y de estos 11 (3,13% 95% IC 1,76-5,52%) eran asintomáticos. No se identificaron asociaciones con factores de riesgo de infección. El CLIA IgG tuvo una concordancia moderada (> 962 muestras) con LFA IgG y ELFA IgM, pero mínima con el LFA IgM. Conclusiones: Nuestro informe es el primero en América Latina sobre tasas de seroprevalencia y seroconversión en trabajadores médicos de la salud. La tasa relativamente alta (> 3%) de trabajadores de la salud asintomáticos con evidencia de infección previa por SARS-CoV-2 resalta la necesidad de realizar pruebas de detección de infección en esta población para prevenir la propagación de la infección.
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Humanos , Masculino , Femenino , Adulto , Persona de Mediana Edad , Personal de Salud , Seroconversión , SARS-CoV-2 , Estudios Seroepidemiológicos , Prevalencia , Factores de Riesgo , Colombia , Atención a la Salud , COVID-19 , Grupos ProfesionalesRESUMEN
The origin and function of blood IgM+IgD+CD27+ B cells is controversial, and they are considered a heterogeneous population. Previous staining of circulating B cells of healthy donors with rotavirus fluorescent virus-like particles allowed us to differentiate two subsets of IgM+IgD+CD27+: IgMhi and IgMlo B cells. Here, we confirmed this finding and compared the phenotype, transcriptome, in vitro function, and Ig gene repertoire of these two subsets. Eleven markers phenotypically discriminated both subsets (CD1c, CD69, IL21R, CD27, MTG, CD45RB, CD5, CD184, CD23, BAFFR, and CD38) with the IgMhi phenotypically resembling previously reported marginal zone B cells and the IgMlo resembling both naïve and memory B cells. Transcriptomic analysis showed that both subpopulations clustered close to germinal center-experienced IgM only B cells with a Principal Component Analysis, but differed in expression of 78 genes. Moreover, IgMhi B cells expressed genes characteristic of previously reported marginal zone B cells. After stimulation with CpG and cytokines, significantly (p < 0.05) higher frequencies (62.5%) of IgMhi B cells proliferated, compared with IgMlo B cells (35.37%), and differentiated to antibody secreting cells (14.22% for IgMhi and 7.19% for IgMlo). IgMhi B cells had significantly (p < 0.0007) higher frequencies of mutations in IGHV and IGKV regions, IgMlo B cells had higher usage of IGHJ6 genes (p < 0.0001), and both subsets differed in their HCDR3 properties. IgMhi B cells shared most of their shared IGH clonotypes with IgM only memory B cells, and IgMlo B cells with IgMhi B cells. These results support the notion that differential expression of IgM and IgD discriminates two subpopulations of human circulating IgM+IgD+CD27+ B cells, with the IgMhi B cells having similarities with previously described marginal zone B cells that passed through germinal centers, and the IgMlo B cells being the least differentiated amongst the IgM+CD27+ subsets.
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Subgrupos de Linfocitos B/fisiología , Linfocitos B/inmunología , Centro Germinal/inmunología , Inmunoglobulina D/metabolismo , Inmunoglobulina M/metabolismo , Adulto , Perfilación de la Expresión Génica , Humanos , Inmunoglobulina D/genética , Cadenas Pesadas de Inmunoglobulina/genética , Inmunoglobulina M/genética , Región Variable de Inmunoglobulina/genética , Inmunofenotipificación , Fenotipo , Análisis de Componente Principal , Miembro 7 de la Superfamilia de Receptores de Factores de Necrosis Tumoral/metabolismoRESUMEN
The genetic basis for sporadic immunodeficiency in patients with 22q11.2 distal deletion syndrome is unknown. We report an adult with a type 1 (D-F) 22q11.2 distal deletion syndrome and recurrent severe infections due to herpes zoster virus, presenting mild T cell lymphopenia and diminished frequency of naive CD4+ T cells, but increased frequencies of central, effector, and terminally differentiated memory T cells. Antigen-specific CD4+ and CD8+ T cells to influenza, rotavirus, and SEB were conserved in the patient, but responses to tetanus toxoid were temporarily undetectable. Exomic sequencing identified the c.20_22dupCGG (NM_002745.4) variant in the remaining MAPK1 gene of the patient, which adds 1 alanine to the polyalanine amino-terminal tract of the protein (p.Ala7dup). The mother, unlike the father, was heterozygote for the variant. Western blot analysis with the patient's activated PBMCs showed a 91% reduction in the MAPK1 protein. Further studies will be necessary to determine whether or not the variant present in the remaining MAPK1 gene of the patient is pathogenic.
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Transforming growth factor ß (TGF-ß) has been shown to play a role in immunity against different pathogens in vitro and against parasites in vivo However, its role in viral infections in vivo is incompletely understood. Using a neonatal mouse model of heterologous rhesus rotavirus (RV) vaccination, we show that the vaccine induced rotavirus-specific CD4 T cells, the majority of which lacked expression of KLRG1 or CD127, and a few regulatory rotavirus-specific CD4 T cells that expressed surface latency-associated peptide (LAP)-TGF-ß. In these mice, inhibiting TGF-ß, with both a neutralizing antibody and an inhibitor of TGF-ß receptor signaling (activin receptor-like kinase 5 inhibitor [ALK5i]), did not change the development or intensity of the mild diarrhea induced by the vaccine, the rotavirus-specific T cell response, or protection against a subsequent challenge with a murine EC-rotavirus. However, mice treated with anti-LAP antibodies had improved protection after a homologous EC-rotavirus challenge, compared with control rhesus rotavirus-immunized mice. Thus, oral vaccination with a heterologous rotavirus stimulates regulatory RV-specific CD4 LAP-positive (LAP+) T cells, and depletion of LAP+ cells increases vaccine-induced protection.IMPORTANCE Despite the introduction of several live attenuated animal and human rotaviruses as efficient oral vaccines, rotaviruses continue to be the leading etiological agent for diarrhea mortality among children under 5 years of age worldwide. Improvement of these vaccines has been partially delayed because immunity to rotaviruses is incompletely understood. In the intestine (where rotavirus replicates), regulatory T cells that express latency-associated peptide (LAP) play a prominent role, which has been explored for many diseases but not specifically for infectious agents. In this paper, we show that neonatal mice given a live oral rotavirus vaccine develop rotavirus-specific LAP+ T cells and that depletion of these cells improves the efficiency of the vaccine. These findings may prove useful for the design of strategies to improve rotavirus vaccines.
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Linfocitos T CD4-Positivos/inmunología , Infecciones por Rotavirus/prevención & control , Vacunas contra Rotavirus/inmunología , Subgrupos de Linfocitos T/inmunología , Factor de Crecimiento Transformador beta/análisis , Administración Oral , Animales , Animales Recién Nacidos , Linfocitos T CD4-Positivos/química , Diarrea/prevención & control , Modelos Animales de Enfermedad , Inmunidad Heteróloga , Ratones , Vacunas contra Rotavirus/administración & dosificación , Subgrupos de Linfocitos T/química , Resultado del TratamientoRESUMEN
La resonancia magnética (RM) de seno es la modalidad diagnóstica más sensible para la detección de cáncer de seno; sin embargo, su especificidad es limitada, pues varía entre el 40 y 80 %. Esto se debe a las características de realce de algunas lesiones benignas que se sobreponen a las de lesiones malignas, y para cuyo diagnóstico se requiere análisis histológico. Para el diagnóstico histológico de estas lesiones que solo se visualizan por RM y no por otro método diagnóstico los procedimientos guiados por RM son la elección. La biopsia guiada por RM se utiliza en pacientes con ultrasonido dirigido negativo. El ROLL (Radioguided Occult Lesión Localization) es una técnica alternativa a la marcación prequirúrgica con alambre de lesiones ocultas y ha sido más ampliamente utilizada en ultrasonido que en RM, con muy buenos resultados. Se obtuvieron de manera retrospectiva los datos de las pacientes que ingresaron al sistema de nuestra institución para la realización de biopsia de seno y marcación de seno guiada por RM. Posteriormente se recopilaron las patologías. Los resultados se tabularon en Excel para su análisis.
Breast magnetic resonance imaging (MRI) is the most sensitive diagnostic modality for the detection of breast cancer; however, its specificity is limited, ranging from 40% to 80%. This is due to the enhancement characteristics of some benign lesions that overlap those of malignant lesions, for which histology is required for diagnosis. For the histological diagnosis of these lesions, which are only visualized by MRI and not by any other diagnostic method, MR-guided procedures are the choice. MR-guided biopsy is used in patients with negative directed ultrasound. ROLL (Radioguided Occult Injury Localization) is an alternative technique to preoperative wire marking of hidden lesions and has been more widely used in ultrasound than in MRI, with very good results. Retrospectively the data of all patients admitted to our center for Breast MRI biopsy and Breast MRI localizations were retrieved. Pathologies were then collected and the results were tabulated in Excel for analysis.
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Humanos , Mama , Biopsia , Neoplasias de la Mama , Imagen por Resonancia MagnéticaRESUMEN
The response of antibody-secreting cells (ASC) induced by dengue has only recently started to be characterized. We propose that young age and previous infections could be simple factors that affect this response. Here, we evaluated the primary and secondary responses of circulating ASC in infants (6-12 months old) and children (1-14 years old) infected with dengue showing different degrees of clinical severity. The ASC response was delayed and of lower magnitude in infants, compared with older children. In primary infection (PI), the total and envelope (E) protein-specific IgM ASC were dominant in infants but not in children, and a negative correlation was found between age and the number of IgM ASC (rho = -0.59, P = 0.03). However, infants with plasma dengue-specific IgG detectable in the acute phase developed an intense ASC response largely dominated by IgG and comparable to that of children with secondary infection (SI). IgM and IgG produced by ASC circulating in PI or SI were highly cross-reactive among the four serotypes. Dengue infection caused the disturbance of B cell subsets, particularly a decrease in the relative frequency of naïve B cells. Higher frequencies of total and E protein-specific IgM ASC in the infants and IgG in the children were associated with clinically severe forms of infection. Therefore, the ASC response induced by dengue is highly influenced by the age at which infection occurs and previous immune status, and its magnitude is a relevant element in the clinical outcome. These results are important in the search for correlates of protection and for determining the ideal age for vaccinating against dengue.
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Anticuerpos Antivirales/inmunología , Células Productoras de Anticuerpos/inmunología , Virus del Dengue/inmunología , Dengue/inmunología , Proteínas del Envoltorio Viral/inmunología , Adolescente , Factores de Edad , Anticuerpos Antivirales/sangre , Células Productoras de Anticuerpos/virología , Subgrupos de Linfocitos B/inmunología , Subgrupos de Linfocitos B/virología , Niño , Preescolar , Reacciones Cruzadas/inmunología , Dengue/sangre , Dengue/virología , Virus del Dengue/genética , Virus del Dengue/fisiología , Ensayo de Immunospot Ligado a Enzimas , Femenino , Interacciones Huésped-Patógeno/inmunología , Humanos , Inmunoglobulina G/sangre , Inmunoglobulina G/inmunología , Inmunoglobulina M/sangre , Inmunoglobulina M/inmunología , Lactante , Masculino , SerogrupoRESUMEN
In addition to previously studied immunological variables, the relative expression of IFNGR2, IFNAR1, CD18, and CD275 (all encoded in chromosome 21) on circulating leucocytes and multifunctional T cells (evaluated by an intracellular cytokine/proliferation assay) were compared between children with Down syndrome (DS) and healthy controls (HC). As previously reported, numbers of lymphocytes, CD4(+) T cells, Treg cells, B cells, and levels of serum IgM were decreased, and levels of IgG and IgA were increased in children with DS. Moreover, the relative expression of CD18 on T and B cells (previously and not previously reported, respectively) were elevated in DS children (p⩽0.01). Age and numbers of B and Treg cells moderately correlated with retrospectively identified infection related hospitalizations (rho: 0.300-0.460, p⩽0.003). Age and the numbers of Treg cells also correlated with prospectively identified infection related hospitalizations. Future studies are necessary to clarify the role of these parameters in the immunity of DS patients.
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Linfocitos B/inmunología , Cromosomas Humanos Par 21/genética , Síndrome de Down/inmunología , Hospitalización/estadística & datos numéricos , Infecciones/inmunología , Subgrupos de Linfocitos T/inmunología , Linfocitos T Reguladores/inmunología , Adolescente , Antígenos CD18/metabolismo , Proliferación Celular , Niño , Preescolar , Citocinas/metabolismo , Síndrome de Down/complicaciones , Síndrome de Down/epidemiología , Femenino , Humanos , Ligando Coestimulador de Linfocitos T Inducibles/metabolismo , Lactante , Infecciones/complicaciones , Infecciones/epidemiología , Activación de Linfocitos , Masculino , Receptor de Interferón alfa y beta/genética , Receptor de Interferón alfa y beta/metabolismo , Receptores de Interferón/genética , Receptores de Interferón/metabolismoRESUMEN
Circulating human IgM expressing memory B cells have been incompletely characterized. Here, we compared the phenotype and in vitro functional response (capacity to proliferate and differentiate to antibody secreting cells) in response to CpG and a cytokine cocktail (IL-2, IL-6, and IL-10) of sorted naïve B cells, IgM memory B cells and isotype-switched circulating memory B cells. Compared to naïve B cells, IgM memory B cells had lower integrated mean fluorescence intensity (iMFI) of BAFF-R, CD38, CD73, and IL-21R, but higher iMFI of CD95, CD11c, TLR9, PD-1, and CD122. Compared to switched memory B cells, IgM memory B cells had higher iMFI of BAFF-R, PD-1, IL-21R, TLR9, and CD122, but lower iMFI of CD38, CD95, and CD73. Four days after receiving the CpG/cytokine cocktail, higher frequencies of IgM than switched memory B cells-and these in turn greater than naïve cells-proliferated and differentiated to antibody secreting cells. At this time point, a small percentage (median of 7.6%) of stimulated IgM memory B cells changed isotype to IgG. Thus, among the heterogeneous population of human circulating IgM memory B cells a subset is capable of a rapid functional response to a CpG/cytokine stimulus in vitro.
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Subgrupos de Linfocitos B/citología , Linfocitos B/citología , Diferenciación Celular/inmunología , Proliferación Celular/fisiología , Inmunoglobulina M/inmunología , Subgrupos de Linfocitos B/efectos de los fármacos , Subgrupos de Linfocitos B/inmunología , Linfocitos B/efectos de los fármacos , Linfocitos B/inmunología , Diferenciación Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Humanos , Cambio de Clase de Inmunoglobulina , Memoria Inmunológica/efectos de los fármacos , Memoria Inmunológica/inmunología , Interleucina-10/farmacología , Interleucina-2/farmacología , Interleucina-6/farmacologíaRESUMEN
Previously, we showed that infecting human intestinal epithelial cells (Caco-2) with rotavirus (RV) increases the release of extracellular vesicles (EVs) with an immunomodulatory function that, upon concentration at 100,000×g, present buoyant densities on a sucrose gradient of between 1.10 to 1.18 g/ml (characteristic of exosomes) and higher than 1.24 g/ml (proposed for apoptotic bodies). The effect of cellular death induced by RV on the composition of these EV is unknown. Here, we evaluated exosome (CD63, Hsc70, and AChE) and apoptotic body (histone H3) markers in EVs isolated by differential centrifugation (4000×g, 10,000×g, and 100,000×g) or filtration/ultracentrifugation (100,000×g) protocols. When we infected cells in the presence of caspase inhibitors, Hsc70 and AChE diminished in EVs obtained at 100,000×g, but not in EVs obtained at 4000×g or 10,000×g. In addition, caspase inhibitors decreased CD63 and AChE in vesicles with low and high buoyant densities. Without caspase inhibitors, RV infection increased exosome markers in all of the EVs obtained by differential centrifugation. However, CD63 preferentially localized in the 100,000×g fraction and H3 only increased in EVs concentrated at 100,000×g and with high buoyant densities on a sucrose gradient. Thus, RV infection increases the release of EVs that, upon concentration at 100,000×g, are composed by exosomes and apoptotic bodies, which can partially be separated using sucrose gradients.
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Exosomas/metabolismo , Vesículas Extracelulares/metabolismo , Rotavirus/fisiología , Acetilcolinesterasa/metabolismo , Apoptosis/efectos de los fármacos , Biomarcadores/metabolismo , Células CACO-2 , Inhibidores de Caspasas/toxicidad , Vesículas Extracelulares/virología , Proteínas del Choque Térmico HSC70/metabolismo , Histonas/metabolismo , Humanos , Tetraspanina 30/metabolismo , Ultracentrifugación , Replicación Viral/efectos de los fármacosRESUMEN
Frequencies of circulating T cells producing IFN-γ, TNF-α, and IL-2, and percentages of T cells proliferating after stimulation with rotavirus (RV), tetanus toxoid, and influenza were evaluated in PBMC derived from healthy adults and children. In addition, the potential anergic state of RV-specific T cells was analyzed by stimulation of PBMC with RV antigen in the presence of three anergy inhibitors (rIL-2, rIL-12, or DGKα-i). The quality and magnitude of RV-T cell responses were significantly lower than those of tetanus toxoid and influenza antigens. RV-CD4 T cell response was enriched in monofunctional IFN-γ(+) cells, while influenza-CD4 and tetanus toxoid-CD4 T cell responses were enriched in multifunctional T cells. Moreover, rIL-2--unlike rIL-12 or DGKα-i--increased the frequencies of RV-CD4 TNF-α(+), CD4 IFN-γ(+), and CD8 IFN-γ(+) cells. Thus, circulating RV-T cells seem to have a relatively poor functional profile that may be partially reversed in vitro by the addition of rIL-2.
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Infecciones por Rotavirus/virología , Rotavirus/fisiología , Linfocitos T/fisiología , Adulto , Proliferación Celular , Niño , Preescolar , Citocinas/genética , Citocinas/metabolismo , Regulación de la Expresión Génica/inmunología , Humanos , Vacunas contra la Influenza , Persona de Mediana Edad , Rotavirus/inmunología , Infecciones por Rotavirus/inmunología , Linfocitos T/efectos de los fármacos , Linfocitos T/inmunología , Toxoide Tetánico , Adulto JovenRESUMEN
The mechanisms that contribute to the maintenance of serological memory are still unclear. Rotavirus (RV) memory B cells (mBc) are enriched in IgM(+) and CD27- subpopulations, which are associated with autoimmune diseases pathogenesis. In patients with autoimmune diseases treated with Rituximab (RTX), some autoantibodies (auto-Abs) decrease after treatment, but other auto-Abs and pathogen-specific IgG Abs remain unchanged. Thus, maintenance of autoimmune and pathogen-specific serological memory may depend on the type of antigen and/or Ab isotype evaluated. Antigen-specific mBc and antigen-specific Abs of different isotypes have not been simultaneously assessed in patients after RTX treatment. To study the relationship between mBc subpopulations and serological memory we characterized total, RV- and tetanus toxoid (TT)-specific mBc by flow cytometry in patients with autoimmune diseases before and after treatment with RTX. We also measured total, RV- and TT-Abs, and some auto-Abs by kinetic nephelometry, ELISA, and EliA tests, respectively. Minor differences were observed between the relative frequencies of RV-mBc in healthy controls and patients with autoimmune disease. After RTX treatment, naïve Bc and total, RV- and TT-specific mBc [IgM(+), switched (IgA(+)/IgG(+)), IgM(+) only, IgD(+) only, and CD27- (IgA(+)/IgG(+)/IgM(+))] were significantly diminished. An important decrease in total plasma IgM and minor decreases in total IgG and IgA levels were also observed. IgM rheumatoid factor, IgG anti-CCP, and IgG anti-dsDNA were significantly diminished. In contrast, RV-IgA, RV-IgG and RV-IgG1, and TT-IgG titers remained stable. In conclusion, in patients with autoimmunity, serological memory against RV and TT seem to be maintained by long-lived plasma cells, unaffected by RTX, and an important proportion of total IgM and serological memory against some auto-antigens seem to be maintained by short-lived plasma cells, dependent on mBc precursors depleted by RTX.
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Anticuerpos Monoclonales de Origen Murino/farmacología , Linfocitos B/efectos de los fármacos , Linfocitos B/inmunología , Memoria Inmunológica/efectos de los fármacos , Depleción Linfocítica/métodos , Rotavirus/inmunología , Adulto , Anciano , Autoantígenos/inmunología , Subgrupos de Linfocitos B/efectos de los fármacos , Subgrupos de Linfocitos B/inmunología , Femenino , Humanos , Inmunoglobulina M/sangre , Masculino , Persona de Mediana Edad , Rituximab , Especificidad de la EspecieRESUMEN
Using a consensus epitope prediction approach, three rotavirus (RV) peptides that induce cytokine secretion by CD4 T cells from healthy volunteers were identified. The peptides were shown to bind HLA-DRB1*0101 and then used to generate MHC II tetramers. RV specific T cell lines specific for one of the three peptides studied were restricted by MHC class II molecules and contained T cells that bound the tetramer and secreted cytokines upon activation with the peptide. The majority of RV and Flu tetramer(+) CD4 T cells in healthy volunteers expressed markers of antigen experienced T cells, but only RV specific CD4 T cells expressed intestinal homing receptors. CD4 T cells from children that received a RV vaccine, but not placebo recipients, were stained with the RV-VP6 tetramer and also expressed intestinal homing receptors. Circulating RV-specific CD4 T cells represent a unique subset that expresses intestinal homing receptors.
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Linfocitos T CD4-Positivos/inmunología , Antígenos de Histocompatibilidad Clase II/inmunología , Integrinas/genética , Intestinos/inmunología , Receptores CCR/genética , Receptores Virales/genética , Infecciones por Rotavirus/inmunología , Rotavirus/inmunología , Adolescente , Adulto , Niño , Femenino , Antígenos de Histocompatibilidad Clase II/química , Antígenos de Histocompatibilidad Clase II/genética , Humanos , Integrinas/inmunología , Intestinos/virología , Masculino , Receptores CCR/inmunología , Receptores Virales/inmunología , Rotavirus/genética , Infecciones por Rotavirus/genética , Infecciones por Rotavirus/virología , Especificidad de la Especie , Proteínas Virales/genética , Proteínas Virales/inmunología , Adulto JovenRESUMEN
Rotavirus (RV)-specific secretory immunoglobulin (RV-SIg) has been previously detected in serum of naturally RV infected children and shown to reflect the intestinal Ig immune response. Total plasma SIgA and plasma RV-SIg were evaluated by ELISA in children with gastroenteritis due or not due to RV infection and in 50 children vaccinated with the attenuated RIX4414 human RV vaccine and 62 placebo recipients. RV-SIg was only detected in children with evidence of previous RV infection or with acute RV gastroenteritis. Vaccinees had higher RV-SIg titers than placebo recipients and RV-SIg titers increased after the second vaccine dose. RV-SIg measured after the second dose correlated with protection when vaccinees and placebo recipients were analyzed jointly. RV-SIg may serve as a valuable correlate of protection for RV vaccines.
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Gastroenteritis/inmunología , Inmunoglobulina A Secretora/sangre , Plasma/inmunología , Infecciones por Rotavirus/inmunología , Vacunas contra Rotavirus/inmunología , Adulto , Ensayo de Inmunoadsorción Enzimática , Femenino , Gastroenteritis/virología , Humanos , Lactante , Masculino , Placebos/administración & dosificación , Infecciones por Rotavirus/virología , Vacunas contra Rotavirus/administración & dosificaciónRESUMEN
Protective immunity to rotavirus (RV) is primarily mediated by antibodies produced by RV-specific memory B cells (RV-mBc). Of note, most of these cells express IgM, but the function of this subset is poorly understood. Here, using limiting dilution assays of highly sort-purified human IgM(+) mBc, we found that 62% and 21% of total (non-antigen-specific) IgM(+) and RV-IgM(+) mBc, respectively, switched in vitro to IgG production after polyclonal stimulation. Moreover, in these assays, the median cloning efficiencies of total IgM(+) (17%) and RV-IgM(+) (7%) mBc were lower than those of the corresponding switched (IgG(+) IgA(+)) total (34%) and RV-mBc (17%), leading to an underestimate of their actual frequency. In order to evaluate the in vivo role of IgM(+) RV-mBc in antiviral immunity, NOD/Shi-scid interleukin-2 receptor-deficient (IL-2Rγ(null)) immunodeficient mice were adoptively transferred highly purified human IgM(+) mBc and infected with virulent murine rotavirus. These mice developed high titers of serum human RV-IgM and IgG and had significantly lower levels than control mice of both antigenemia and viremia. Finally, we determined that human RV-IgM(+) mBc are phenotypically diverse and significantly enriched in the IgM(hi) IgD(low) subset. Thus, RV-IgM(+) mBc are heterogeneous, occur more frequently than estimated by traditional limiting dilution analysis, have the capacity to switch Ig class in vitro as well as in vivo, and can mediate systemic antiviral immunity.
Asunto(s)
Inmunoglobulina M/química , Rotavirus/metabolismo , Animales , Linfocitos B/citología , Separación Celular , Clonación Molecular , Ensayo de Inmunoadsorción Enzimática/métodos , Citometría de Flujo , Humanos , Inmunoglobulina A/química , Inmunoglobulina D/química , Inmunoglobulina G , Inmunoglobulina M/metabolismo , Memoria Inmunológica , Subunidad gamma Común de Receptores de Interleucina/metabolismo , Ratones , Ratones Endogámicos NOD , Ratones Transgénicos , Fenotipo , Infecciones por Rotavirus/metabolismoRESUMEN
Selected topics in the field of rotavirus immunity are reviewed focusing on recent developments that may improve efficacy and safety of current and future vaccines. Rotaviruses (RVs) have developed multiple mechanisms to evade interferon (IFN)-mediated innate immunity. Compared to more developed regions of the world, protection induced by natural infection and vaccination is reduced in developing countries where, among other factors, high viral challenge loads are common and where infants are infected at an early age. Studies in developing countries indicate that rotavirus-specific serum IgA levels are not an optimal correlate of protection following vaccination, and better correlates need to be identified. Protection against rotavirus following vaccination is substantially heterotypic; nonetheless, a role for homotypic immunity in selection of circulating postvaccination strains needs further study.