Efficacy and safety of neoadjuvant chemotherapy combined with PD-1 antibody for esophageal squamous cell carcinoma in the real world / 中华肿瘤杂志

Objective: To evaluate the efficacy and safety of neoadjuvant chemotherapy combined with programmed death-1 (PD-1) antibody in operable, borderline or potentially resectable locally advanced esophageal squamous cell carcinoma(ESCC) in the real world. Methods: The study retrospectively analyzed 28 patients with operable or potentially resectable locally advanced ESCC patients treated with preoperative chemotherapy combined with PD-1 inhibitor in Nanjing Drum Tower Hospital, Affiliated Hospital of Nanjing University Medical School from April 2020 to March 2021. According to the clinical TNM staging system of the 8th edition of the American Joint Committee on Cancer, there were 1, 15, 10, 1 and 1 case of stage Ⅱ, Ⅲ, ⅣA, ⅣB and unknown stage respectively. The treatment was two cycle of dual drug chemotherapy regimen including taxane plus platinum or fluorouracil combined with PD-1 antibody followed by tumor response assessment and surgery if the patient was eligible for resection. Results: Of the 28 patients, 1, 2, 3 and 4 cycles of chemotherapy combined with PD-1 antibody treatment completed in 1, 21, 5, and 1 patient, respectively. Objective response rate (ORR) was 71.4% (20/28), and disease control rate (DCR) was 100% (28/28). The incidence of adverse events exceeding grade 3 levels was 21.4% (6/28), including 3 neutropenia, 1 leukopenia, 1 thrombocytopenia and 1 immune hepatitis. There was no treatment-related death. Of the 23 patients underwent surgery, R0 resection rate was 87.0% (20/23), 13 patients had down staged to the T1-2N0M0 I stage, the pCR rate was 17.3% (4/23), and the pCR rate of primary tumor was 21.7% (5/23). Four patients received definitive chemoradiotherapy. One patient rejected surgery and other treatment after achieved PR response. Conclusion: Neoadjuvant chemotherapy combined PD-1 inhibitor is safe and has high efficacy in operable, borderline or potentially resectable locally advanced ESCC, and it is a promising regimen.

A prediction model of pathological complete response in patients with locally advanced rectal cancer after PD-1 antibody combined with total neoadjuvant chemoradiotherapy based on MRI radiomics / 中华胃肠外科杂志

Objective: To construct a prediction model of pathologic complete response (pCR) in locally advanced rectal cancer patients who received programmed cell death protein-1 (PD-1) antibody and total neoadjuvant chemoradiotherapy by using radiomics based on MR imaging data and to investigate its predictive value. Methods: A clinical diagnostic test study was carried out. Clinicopathalogical and radiological data of 38 patients with middle-low rectal cancer who received PD-1 antibody combined with total neoadjuvant chemoradiotherapy and underwent TME surgery from January 2019 to September 2021 in our hospital were retrospectively collected. Among 38 patients, 23 were males and 15 were females with a median age of 68 (47-79) years and 13 (34.2%) a chieved pCR. These 38 patients were stratified and randomly divided into the training group (n=26) and test group (n=12) for modeling. All the patients underwent rectal MRI before treatment. The clinical, imaging and radiomics features of all the patients were collected, and the clinical feature model and radiomics model were constructed. The receiver operating characteristic (ROC) curves of each model were drawn, and the constructed model was evaluated through the area under the curve (AUC), accuracy, sensitivity, specificity, positive predictive value and negative predictive value. Results: There were no significant differences in age, gender, primary location of tumor and postoperative pathology between the two groups (all P>0.05). Forty-one features were extracted from region of interest in each modality, including 9 first-order features, 24 gray level co-occurrence matrix features and 8 shape features. From 38 patients, 41 features were extracted from each imaging modality of baseline and preoperative DWI and T2WI images, totally 164 features. Only 4 features were preserved after correlation analysis between each pair of features and t-test between pCR and non-pCR subjects. After LASSO cross validation, only the first-order skewness of the baseline DWI image before treatment and the volume in the baseline T2WI image before treatment were retained. The area under the curve, sensitivity, specificity, positive and negative predictive values of the prediction model established by applying these two features in the training group and the test group were 0.856 and 0.844, 77.8% and 100.0%, 88.2% and 75.0%, 77.8% and 66.7%, 88.2% and 100.0%, respectively. The decision curve analysis of the radiomics model showed that the strategy of this model in predicting pCR was better than that in treating all the patients as pCR and that in treating all the patients as non-pCR. Conclusion: The pCR prediction model for rectal cancer patients receiving PD-1 antibody combined with total neoadjuvant radiochemotherapy based on MRI radiomics has the potential to be used in clinical screening or rectal cancer patients who can be spared from radical surgery.

Anti-PD-1 and anti-PD-l1 antibodies as immunotherapy against cancer: a structural perspective

ABSTRACT Programmed cell death protein 1 (PD-1) and its ligand, programmed death-ligand-1 (PD-L1), play key roles in the suppression of the cytotoxic activity of T cells. PD-L1 is overexpressed on various types of cancer cells, leading to immune evasion. In the past decade, therapeutic antibodies that target the PD-1/PD-L1 axis have been developed to inhibit the immune suppression triggered by these two proteins. At present, five antibodies (two anti-PD-1 and three anti-PD-L1) have received approval by regulatory agencies in the US and Europe. In this work, we aimed to review their clinical applications and adverse effects. Furthermore, using their reported crystal structures, we discuss the similarities and differences between the PD-1/PD-L1 interface and the epitopes that are recognized by the antibodies. Detailed analyses of the contact residues involved in the ligand-receptor and target-antibody interactions have shown partial overlap. Altogether, the data presented here demonstrate that: (1) in contrast to other therapeutic antibodies, anti-PD-1/PD-L1 has a wide range of clinical applications; (2) these targeted therapies are not exempt from adverse effects; and (3) the characterization of the structural domains that are recognized by the antibodies can guide the development of new PD-1- and PD-L1-blocking agents. (REV INVEST CLIN. 2021;73(1):8-16)

Caracterización de los anticuerpos anti-HLA en posibles receptores cubanos de trasplante cardiaco / Characterization of anti-HLA antibodies in Cuban possible receptors of heart transplant

Introducción: En la supervivencia del corazón trasplantado son de importancia el empleo de los anticuerpos contra el sistema principal de histocompatibilidad (anticuerpos anti-HLA). Hace seis años se introdujo en Cuba el porcentaje de anticuerpos anti-HLA frente a panel (PRA) por método de ensayo de inmunoabsorción ligado a enzima (ELISA) como parte de las pruebas de compatibilidad pretrasplante de los receptores de trasplante cardiaco. Objetivo: Caracterizar los anticuerpos anti-HLA en pacientes receptores cubanos de trasplante cardiaco. Métodos: Entre septiembre de 2013 y abril de 2017 se les realizó el PRA por ELISA a 38 muestras de pacientes recibidas en el laboratorio de histocompatibilidad del Instituto de Hematología e Inmunología. Se utilizó la comparación de proporciones para el análisis estadístico. Resultados: El 47,4 por ciento de los pacientes estudiados presentó anticuerpos anti-HLA, fueron los más frecuentes los de clase I. La proporción de pacientes con PRA del 0 por ciento fue mayor en PRA clase II que en I (p: 0,0027). Mientras que fue mayor la proporción de pacientes con PRA clase I entre el 20 y el 75 por ciento (p: 0,0046). El 77,8 por ciento de los pacientes tuvo un PRA clase I mayor al 10 por ciento y en el PRA clase II alcanzó el 80 por ciento. Conclusiones: El porcentaje de anticuerpos anti-HLA frente a panel por método de ensayo de inmunoabsorción ligado a enzima permitió una mejor caracterización de los anticuerpos anti-HLA, lo que contribuyó a mejorar la compatibilidad en este tipo de paciente(AU)

Introduction: In survival after heart transplantation, the use of antibodies against the main histocompatibility system (anti-HLA antibodies) is important. Six years ago, the percentage of anti-HLA antibodies against panel (PRA) by enzyme-linked immunosorbent assay (ELISA) method was introduced in Cuba as part of the pre-transplant compatibility tests of heart transplant recipients. Objective: To characterize anti-HLA antibodies in Cuban heart transplant recipients. Methods: Between September 2013 and April 2017, PRA by ELISA was performed on 38 patient samples received in the histocompatibility laboratory of the Institute of Hematology and Immunology. Comparison of proportions was used for statistical analysis. Results: 47.4 percent of the study patients presented anti-HLA antibodies; those in class were the most frequent. The proportion of patients with PRA of 0 percent was higher in PRA class II than in class I (p=0.0027). The proportion of patients with PRA class I was greater, accounting for 20-75 percent (p=0.0046). 77.8 percent of the patients had a class I PRA greater than 10 percent, while in class II PRA it reached 80 percent. Conclusions: The percentage of anti-HLA antibodies versus a panel of enzyme linked immunosorbent assay method allowed better characterization of anti-HLA antibodies, which contributed to improving compatibility in this type of patient(AU)

Obtención de una versión IgG1 de ratón del rituximab para detectar la molécula CD20 humana / Obtaining a mouse IgG1 version of rituximab to detect the human CD20 molecule

Introducción: El rituximab, anticuerpo quimérico que reconoce la molécula CD20 humana, se ha utilizado en el tratamiento de diversos trastornos linfoproliferativos de células B. Para la selección de los potenciales beneficiarios del tratamiento con rituximab se han desarrollado técnicas que, mediante el uso de anticuerpos monoclonales, detectan la presencia del CD20 en los linfocitos de estos pacientes. Objetivo: Obtener y caracterizar un anticuerpo recombinante IgG1 de ratón específico para la molécula CD20 humana, que contenga las regiones variables del anticuerpo rituximab. Métodos: Para la expresión estable del anticuerpo recombinante se empleó la transducción lentiviral de células de embrión de riñón humano (HEK293). La caracterización inmunoquímica del anticuerpo se realizó por la técnica de Western Blot y su capacidad de reconocimiento de la molécula CD20 humana se evaluó por citometría de flujo e inmunohistoquímica. Resultados: Se obtuvo el anticuerpo 1F5 que reconoce, por citometría de flujo, la molécula CD20 en líneas celulares humanas de origen linfoide, así como en células de sangre periférica de humanos sanos y pacientes con trstornos linfoproliferativos de células B. Sin embargo, la técnica de inmunohistoquímica solo permitió detectar con este anticuerpo la molécula CD20 en tejidos frescos, no así en los embebidos en parafina. Conclusiones: Este trabajo sugiere las potencialidades del uso del anticuerpo 1F5 para las mediciones de la expresión de CD20 por citometría de flujo en pacientes con leucemias B o linfomas B avanzados en fase de leucemización. Esto complementaría los estudios para la selección apropiada de pacientes para el tratamiento con el rituximab(AU)

Introduction: Rituximab, chimeric antibody specific for human CD20 molecule, has been widely used in the treatment of several B-cell linfoproliferative disorders. For the selection of patients with the greatest potential to benefit from the therapy with rituximab, a number of techniques using monoclonal antibodies have been developed to detect the CD20 molecule. Objective: To obtain and to characterize a mouse IgG1 recombinant antibody, specific for human CD20, that contains the variable regions of rituximab. Methods: The lentiviral transduction of human embryonic kidney cells (HEK293) was used for the stable expression of the recombinant antibody. The immunochemical characterization of the antibody was performed by Western Blot and the recognition of CD20 was evaluated by immunohistochemistry and flow cytometry. Results: We generated the antibody 1F5, able to recognize by flow cytometry the CD20 molecule expressed on lymphoid human cell lines, as well as peripheral blood mononuclear cells from healthy donors and patients with B-cell lymphoproliferative disorders. However, 1F5 antibody detected the CD20 molecule on fresh tissues, but not on formalin-fixed paraffin embedded tissues,by immunohistochemistry. Conclusions: This work suggests the potential use of 1F5 antibody for the measurement of CD20 expression by flow cytometry in patients with B-cell leukemias or B-cell lymphomas in phase of leukemization. This could complement the studies to ensure the appropriate selection of patients for the treatment with rituximab(AU)

Seguridad y efecto del uso compasivo del anticuerpo monoclonal anti-CD20 CIMABior® / Safety and response to treatment of compassionate use of an anti-CD20 monoclonal antibody CIMABior®

Introducción: el uso de anticuerpos monoclonales transformó el tratamiento de los linfomas no hodgkinianos. El Centro de Inmunología Molecular generó un anticuerpo anti-CD20 (CIMABior®) biosimilar del rituximab, que se ha caracterizado desde el punto de vista biológico, pero la seguridad y eficacia aún están en estudio. Objetivo: evaluar la seguridad y la respuesta al tratamiento con CIMABior ®, en pacientes con síndromes linfoproliferativos de células B tratados con intención compasiva. Métodos: estudio multicéntrico, exploratorio, con dos grupos de tratamiento (monoterapia o combinado con quimioterapia) no controlado, ni aleatorizado. Se incluyeron adultos con linfomas no hodgkinianos y leucemia linfocítica crónica, no elegibles para el ensayo clínico en ejecución con este producto. Se determinó la frecuencia de eventos adversos y se caracterizaron. La respuesta al tratamiento se definió como: remisión completa, remisión parcial, enfermedad estable o en progresión. Se calculó la tasa de respuesta objetiva (remisión completa más remisión parcial) con el intervalo de confianza al 95 por ciento, se evaluó la relación de algunas variables con la respuesta y se estimó la razón de Odss. Como medida de balance beneficio-riesgo se estimó el factor de Bayes. Resultados: los eventos adversos más frecuentes fueron: temblor (12,8 por ciento) y fiebre (10,3 por ciento). Los relacionados con el producto (43,4 por ciento) fueron leves o moderados y evolucionaron hacia la recuperación. No se informó muerte asociada directamente al tratamiento. Se constató respuesta objetiva global de 71,2 por ciento (59,6 por ciento de remisiones completas y 11,5 por ciento, parciales). La respuesta objetiva en el grupo de monoterapia fue de 66,7 por ciento y de 73,0 por ciento en el grupo de CIMABior® más quimioterapia, con remisiones completas de 46,7 por ciento y 64,9 por ciento, respectivamente. Conclusiones: el AcM CIMABior® es seguro, bien tolerado y se demostraron evidencias de efecto. El tratamiento aportó un beneficio clínico superior al riesgo de desarrollar algún evento adverso grave(AU)

Introduction : The use of monoclonal antibodies transformed the treatment of non-Hodgkin lymphomas. The Center of Molecular Immunology created an anti-CD20 monoclonal antibody (CIMABior®), biosimilar of rituximab, which has been characterized from a biological point of view, but the safety and effectiveness are still being studied. Objective: Evaluate the safety and response to treatment, in patients with B-cell malignancies with compassionate use of CIMABior®. Methods : A multicenter, exploratory, non-controlled, non-randomized study was conducted with two variants of treatments (monotherapy or combined with chemotherapy). Adults with non-Hodgkin lymphomas and chronic lymphocytic leukemia not eligible for clinical trial with this product were included. Frequency of adverse events was calculated and those were characterized. The response to treatment was defined as: complete response, partial response, stable disease or progressive disease. Overall response rate (complete plus partial remission) was calculated with 95 percent confidence interval. The relation of some variables with response was estimated per Odss ratio. As a measure of the benefit-risk balance, the Bayes factor was estimated. Results : The more frequent adverse events were: tremors (12.8 percent) and fever (10.3 percent). Those related to the product (43.4 percent) were minor and evolved to recovery. There were no deaths in reference to the treatment. An overall response of 71.2 percent was confirmed (59.6 percent complete remissions and 11.5 percent partial remission). The monotherapy group objective response was 66.7 percent and 73.0 percent in the CIMABior® plus chemotherapy group, with complete remissions of 46.7 percent and 64.9 percent respectively. Conclusions: The monoclonal antibodies CIMABor® is safe, well tolerated and evidences of its effectiveness was demonstrated. The treatment provided a superior clinical benefit to the risk of developing a severe adverse event(AU)

Presente y futuro de los anticuerpos recombinantes terapéuticos / Present and future of therapeutic recombinant antibodies

Los anticuerpos constituyen un componente fundamental del sistema inmune, permitiendo el reconocimiento con alta especificidad y posterior destrucción de moléculas extrañas. Los anticuerpos monoclonales, producidos por la tecnología del hibridoma, presentan desventajas para su uso en terapia humana debido a su origen en una especie diferente. La ingeniería genética posibilitó la utilización de los anticuerpos monoclonales para terapias humanas, generando los anticuerpos recombinantes terapéuticos. Así, los anticuerpos recombinantes se han transformado en un importante grupo de fármacos; con decenas de ellos aprobados para terapia humana y cientos en desarrollo. Se utilizan con éxito como tratamiento para un amplio rango de patologías, tales como cáncer, autoinmunidad e infecciones, siendo desde hace años el biofármaco con mayores ventas. Inicialmente todos los anticuerpos recombinantes terapéuticos presentaban la estructura convencional de los anticuerpos. Sin embargo, más recientemente, se han generado nuevos diseños que no poseen las características estructurales naturales, como los anticuerpos de simple cadena y bi-específicos. Debido al desarrollo y éxito de la tecnología de anticuerpos recombinantes, se espera un aumento constante en el número de anticuerpos terapéuticos contra nuevos blancos, además de la generación de nuevas estructuras, usos y estrategias terapéuticas. En esta revisión, nos centraremos en las características estructurales y los nuevos formatos de anticuerpos, así como su aplicación clínica en el tratamiento de diversas patologías. Además analizaremos los nuevos formatos de anticuerpos que se encuentran en el mercado y la aparición de los anticuerpos biosimilares.

Antibodies are a key component of the immune system, acting in the highly specific recognition and subsequent destruction of foreign molecules. Monoclonal antibodies produced by hybridoma technology have disadvantages for use in human therapy becauseof its origin in a different species. Genetic engineering enabled the use of monoclonalantibodies for human therapies, generating recombinant therapeutic antibodies. Thus, the recombinant antibodies have become an important group of drugs; dozens of them are approved for human therapy and there are hundreds in development. They are successfully used as a treatment for a wide range of pathologies, such as cancer, autoimmunity and infections, being the biopharmaceutical with higher sales. Initially therapeutic recombinant antibodies showed the conventional structure of the antibodies. However, more recently, new designs that do not have natural structural features havebeen generated such as single chain formats and bi-specific antibodies. Due to development and success of recombinant antibody technology, a steady increase in the number of newtherapeutic drugs against new targets is expected in addition to the generation of new structures, uses and therapeutic strategies. In this review, we will focus on their structural features and clinical application in the treatment of various pathologies. We will also discuss new formats of antibodies and the emergence of biosimilar antibodies.

Hacia el control de la diarrea por rotavirus A: ¿podrían los nanoanticuerpos VHH marcar la diferencia? / Controlling rotavirus-associated diarrhea: could single-domain antibody fragments make the difference?

Los rotavirus del grupo A (RVA) constituyen la principal causa de diarrea grave y mortalidad infantil. La porción variable de los anticuerpos de cadena pesada derivados de camélidos presentan una amplia capacidad de unión antigénica (reconocen sitios antigénicos no accesibles a los anticuerpos tradicionales, con elevada afinidad) tienen bajos costos de producción y resultan ideales para las terapias orales. A la fecha, se desarrollaron 2 pares de nanoanticuerpos VHH contra RVA: ARP1-ARP3 y 2KD1-3B2. En este trabajo, exploramos el potencial de ambos grupos de nanoanticuerpos como estrategias de prevención complementarias a la vacunación y como una opción de tratamiento frente a la diarrea asociada a RVA en poblaciones de riesgo. Ambos pares de nanoanticuerpos fueron expresados en diferentes sistemas de producción y mostraron amplia capacidad neutralizante contra diversas cepas de RVA in vitro. También fueron usados en el modelo de ratón lactante, en el que evidenciaron distintos grados de éxito en la prevención o el tratamiento de la diarrea inducida por RVA. Es interesante destacar que la mitigación de los síntomas también se logró con ARP1 liofilizado y conservado, por lo que podría ser utilizado en áreas donde es difícil mantener la cadena de frío. Asimismo, 3B2 fue testeado en una prueba preclínica utilizando como modelo al cerdo gnotobiótico, al cual confirió completa protección contra la diarrea inducida por RVA. ARP1 fue usado en la primera prueba clínica de nanoanticuerpos VHH contra RVA, donde redujo significativamente las deposiciones en pacientes pediátricos con diarrea positivos para RVA, sin evidenciar ninguna reacción adversa

Group A Rotavirus (RVA) remains a leading cause of severe diarrhea and child mortality. The variable domain of camelid heavy chain antibodies (VHH) display potent antigen-binding capacity, have low production costs and are suitable for oral therapies. Two sets of anti-RVA VHHs have been developed: ARP1-ARP3; 2KD1-3B2. Here, we explore the potential of both sets as a prevention strategy complementary to vaccination and a treatment option against RVA-associated diarrhea in endangered populations. Both sets have been expressed in multiple production systems, showing extensive neutralizing capacity against strains of RVA in vitro. They were also tested in the neonatal mouse model with various degrees of success in preventing or treating RVA-induced diarrhea. Interestingly, mitigation of the symptoms was also achieved with freeze-dried ARP1, so that it could be applied in areas where cold chains are difficult to maintain. 3B2 was tested in a pre-clinical trial involving gnotobiotic piglets where it conferred complete protection against RVA-induced diarrhea. ARP1 was used in the first clinical trial for anti-RVA VHHs, successfully reducing stool output in infants with RVA diarrhea, with no detected side effects

Retinopathy of Prematurity among Very-Low-Birth-Weight Infants in Korea: Incidence, Treatment, and Risk Factors

This study was conducted to describe the incidence, risk factors, and current treatment status of retinopathy of prematurity (ROP) in very-low-birth-weight (VLBW) infants registered in the Korean Neonatal Network database. Medical records of 2,009 VLBW infants born between January 2013 and June 2014 who underwent examination by an ophthalmologist were reviewed. The total incidence of ROP was 34.1%. Of the patients, 11.6% showed ROP stage > or = 3 and 11.5% received treatment of VLBW. Among all infants who received treatment of ROP, 63.6% underwent operation only; 16.9%, anti-vascular endothelial growth factor (anti-VEGF) treatment only; and 19.5%, both operation and anti-VEGF treatment. The mean gestational age (GA) and birth weight (BW) were significantly lower and the prevalence rates of respiratory distress syndrome, patent ductus arteriosus (PDA), invasive ventilator duration, and sepsis were significantly higher in the VLBW infants with ROP than in those without ROP. In the multivariable logistic regression analysis, PDA (odd ratio [OR], 2.1; 95% confidence interval [CI], 1.11-3.79) and invasive ventilator duration (OR, 1.0; 95% CI, 1.00-1.02) were significant risk factors of ROP and ROP stage > or = 3. In conclusion, the high incidence of ROP is associated with low GA and BW, and attempt to reduce the aforementioned risk factors could reduce the incidence of ROP stage > or = 3 in VLBW infants.

Soroprevalência de anticorpos anti-Toxoplasma gondii em indígenas da etnia Terena, Mato Grosso do Sul, Brasil / Seroprevalencia de anticuerpos anti-Toxoplasma gondii en indígenas de la etnia Terena, Mato Grosso do Sul, Brasil / Seroprevalence of anti-Toxoplasma gondii antibodies among members of the Terena ethnic group, Mato Grosso do Sul, Brazil

Objetivo: avaliar por meio de inquérito soroepidemiológico a presença de anticorpos anti-Toxoplasma gondii na população indígena da etnia Terena, bem como reconhecer os prováveis mecanismos de transmissão do Toxoplasma gondii naquela comunidade. Métodos: para realização da pesquisa, coletou-se sangue venoso de 256 indígenas assintomáticos. O soro obtido do sangue foi congelado a - 20 °C até a realização dos exames. Realizou-se a sorologia por imunofluorescência Indireta (RIFI) e confirmação dos soros positivos por Enzyme-Linked Immunosorbent Assay (ELISA). Resultados: entre os 256 indígenas estudados, 67 (26,17) apresentaram anticorpos de classe IgG anti-T gondii, com títulos iguais ou superiores a 1:16. Não foi encontrada positividade para IgM em nenhuma das amostras analisadas. Conclusões: a soroprevalência de anticorpos anti-T. gondii entre os indígenas da etnia Terena indica que essa população teve um contato anterior com o parasito. O fator de risco identificado como provável responsável pela transmissão foi coabitação entre pessoas e gatos. A prevalência de soropositividade foi maior na faixa etária entre 21 e 25 anos(AU)

Objetivo: evaluar por medio de interrogatorio seroepidemiológico la presencia de anticuerpos anti-Toxoplasma gondii en la población indígena de la etnia Terena, así como reconocer los probables mecanismos de transmisión del Toxoplasma gondii en esa comunidad. Métodos: se recolectó sangre venosa de 256 indígenas asintomáticos. El suero obtenido de la sangre se congeló a - 20 °C hasta la realización de los exámenes. Se hizo la serología por inmunofluorescencia indirecta y la confirmación de los sueros positivos por ELISA (enzyme-linked immunosorbent assay). Resultados: entre los 256 indígenas estudiados, 67 (26,17 por ciento) presentaron anticuerpos de clase IgG anti- Toxoplasma gondii, con títulos iguales o superiores a 1:16. No se encontró positividad para IgM en las muestras analizadas. Conclusiones: la seroprevalencia de anticuerpos anti- Toxoplasma gondii entre los indígenas de la etnia Terena indica que esa población tuvo un contacto anterior con el parásito. El factor de riesgo identificado como probable responsable por la transmisión resultó la cohabitación entre personas y gatos. La prevalencia de seropositividad fue mayor en la franja etaria entre 21 y 25 años(AU)

Objective: by means of seroepidemiological interviews, determine the presence of anti-Toxoplasma gondii antibodies among the native Terena population, and identify the probable transmission mechanisms of Toxoplasma gondii in that community. Methods: venous blood was collected from 256 asymptomatic community members. The blood serum obtained was frozen to -20 °C until the tests were carried out. Indirect immunofluorescence serology was performed and positive sera were confirmed by ELISA (enzyme-linked immunosorbent assay). Results: of the 256 subjects studied, 67 (26.17 percent) had anti-Toxoplasma gondii IgG antibodies, with titers equal to of greater than 1:16. No positive results were obtained for IgM in the samples analyzed. Conclusions: the seroprevalence of anti-Toxoplasma gondii antibodies among members of the Terena ethnic group indicates that this population had a previous contact with the parasite. The risk factor identified as the probable cause of transmission was the presence of cats in households. Seropositivity was highest in the 21-25 age group(AU)

Incidencia del virus herpes simplex en pacientes con infecciones agudas del sistema nervioso central / Incidence of herpes simplex virus infection in patients with acute central nervous system infections

Los Virus Herpes Simple son responsables de una variedad de infecciones a nivel de mucosas bucal y genital, son neurotrópicos, capaces de alojarse en células nerviosas y permanecer latentes con subsecuentes reactivaciones, en algunos casos pueden provocar meningitis y encefalitis. tienen una morbilidad significativa y una mortalidad elevada. El presente estudio tiene como objetivo determinar la incidencia de VHS en la etiología de los síndromes agudos del SNC mediante la detección en suero y LCR de anticuerpos específicos. Se estudiaron 93 muestras pareadas de pacientes con afecciones neurológicas que mostraron resultados negativos en el estudio bacteriológico de LCR y cuya relación Alb-LCR/Alb-suero fue <0,0075. Los anticuerpos fueron detectados por el método de inmunoensayo enzimático Elisa: Enzygnost® anti virus VHS/IgM-IgG (Behring, 1994), donde 1,2% (1/93) de las muestras de suero resultaron positivas para IgM; 89,24% (83/93)de los sueros resultaron positivos para IgG; y 27,39% (20/93) de las muestras de LCR presentaron anti-IgG positivo. La presencia de IgG en LCR sugiere la producción intratecal de estos anticuerpos en el SNC, lo que muestra una participación importante de este agente viral en las infecciones y enfermedades asociadas al SNC

Herpes simplex viruses are agents responsible for a variety of infections on buccal and genital mucosa; they are neurotropic, capable of lodging in the nerve cells and remaining latent with subsequent reactivations; in some cases, they can provoke meningitis and encephalitis; and they have a significant morbidity and are associated with a high mortality. The present project aims to determine HSV’s effect on the etiology of acute central nervous system (CNS) syndromes using the detection of specific antibodies in serum and cerebrospinal fluid. The 93 paired samples from patients with neurological affectations studied demonstrated negative results in the LCR bacteriological study and their Alb-LCR/Alb-serum relation was < 0.0075. Antibodies were detected by the enzymatic immunoassay ELISA method, where 1.2% (1/93) of the serum samples turned out positive for IgM; 89.24% (83/93) of the serum samples resulted positive for IgG; and 27.39% (20/93) of LCR samples were positive for anti-IgG. IgG presence in LCR suggested the intrathecal production of these antibodies inside the CNS, which demonstrates a significant participation by this viral agent in infections and diseases associated with the CNS

Antibodies are challenged.

Studies on antibody were documented as early as in 1890. They are proteins found in blood or other body fluid of vertebrates, and are used by the immune system to identify and neutralize antigens (like foreign objects, pathogens like bacteria and virus etc). Antibodies are dominating the biomedical research field especially detection, imaging and inhibition of biological target molecules, and therapeutics so far. However, recently aptamer has been seen to compete with antibodies in all the above areas. Aptamers are single stranded oligonucleotides or peptides that fold into well defined three dimensional shapes, allowing them to bind their targets with high affinity and specificity. Aptamer technology is relatively new and discovered only in 1990. Because of synthetic origin and similar function as antibodies, they are often termed as chemical antibody. Within 25 years of discovery, the first generation of aptamer drug "Macugen" is already marketed and available for public use. The Global market for aptamer was $236 million in 2010 and is expected to be valued at nearly $1.8 billion by 2014, with a growing compound annual growth rate of 67.5%. Various drugs being on the pipeline for clinical trials this emerging field of medical biotechnology is raising significant interest. This article gives an overview how aptamers are similar yet distinctly different from antibodies in terms of synthesis, handling, and applicability.

High mobility group box 1 as a mediator of endotoxin administration after hemorrhagic shock-primed lung injury

High mobility group box 1 (HMGB1) was discovered as a novel late-acting cytokine that contributes to acute lung injury (ALI). However, the contribution of HMGB1 to two-hit-induced ALI has not been investigated. To examine the participation of HMGB1 in the pathogenesis of ALI caused by the two-hit hypothesis, endotoxin was injected intratracheally in a hemorrhagic shock-primed ALI mouse model. Concentrations of HMGB1 in the lung of the shock group were markedly increased at 16 h (1.63 ± 0.05, compared to the control group: 1.02 ± 0.03; P < 0.05), with the highest concentration being observed at 24 h. In the sham/lipopolysaccharide group, lung HMGB1 concentrations were found to be markedly increased at 24 h (1.98 ± 0.08, compared to the control group: 1.07 ± 0.03; P < 0.05). Administration of lipopolysaccharide to the hemorrhagic shock group resulted in a notable HMGB1 increase by 4 h, with a further increase by 16 h. Intratracheal lipopolysaccharide injection after hemorrhagic shock resulted in the highest lung leak at 16 h (2.68 ± 0.08, compared to the control group: 1.05 ± 0.04; P < 0.05). Compared to the hemorrhagic shock/lipopolysaccharide mice, blockade of HMGB1 at the same time as lipopolysaccharide injection prevented significantly pulmonary tumor necrosis factor-alpha, interleukin-1beta and myeloperoxidase. Lung leak was also markedly reduced at 16 h; blockade of HMGB1 24 h after lipopolysaccharide injection failed to alter lung leak or myeloperoxidase at 48 h. Our observations suggest that HMGB1 plays a key role as a late mediator when lipopolysaccharide is injected after hemorrhagic shock-primed ALI and the kinetics of its release differs from that of one-hit ALI. The therapeutic window to suppress HMGB1 activity should not be delayed to 24 h after the disease onset.

Immune response and neutralization capacity of antibodies produced in young sheep immunized with Crotalus durissus terrificus native or Cobalt-60 irradiated venom / esposta imune e capacidade de neutralização de anticorpos produzidos em ovinos jovens imunizados com veneno de Crotalus durissus terrificus nativo e irradiado com Cobalto 60

The ELISA technique was used to evaluate and compare young ovine humoral immune response during crotalic antiserum production. Animals were clinically evaluated throughout this process, and the neutralizing capacity of antisera raised against natural (NV) and Cobalt-60 irradiated (IrV) venoms of Crotalus durissus terrificus (C.d.t.) was verified by means of in vitro challenges. Three groups of six animals each were used: G1 received NV; G2 was inoculated with IrV; and G3 was used as control. Animals received six immunizations during 84 days at 14-day intervals. ELISA of antibody profile showed significant difference (p<5%) between experimental groups (G1

A técnica de Elisa foi utilizada para avaliar e comparar a resposta imune humoral de ovinos jovens para a produção de soro anticrotálico. Durante o processo de soroprodução, foi realizada a avaliação clínica dos animais. A capacidade de neutralização do soro produzido a partir de veneno de serpente Crotalus durissus terrificus, nativo (VN) e irradiado (VIr) com Cobalto–60 foi verificada por meio de desafios in vitro. Um grupo de seis animais recebeu veneno nativo, o segundo grupo recebeu veneno irradiado e o terceiro grupo foi o controle. Os animais receberam seis imunizações durante 84 dias com intervalo de14 dias. Houve diferença significativa (p<5%) no teste de ELISA do perfil de anticorpos produzidos pelos grupos experimentais (VN

Activación plaquetaria por trombina / Platelet activation by thrombin

Cuando un agonista se une a su receptor específico sobre la membrana plaquetaria se inician una serie de cambios morfológicosy metabólicos que llevan al cambio de forma, agregación y secreción de contenidos granulares. La trombina, serinoproteasa multifuncional y fuerte agonosta plaquetario, tiene dos tipos de receptores sobre la membrana plaquetaria: de alta y de moderada afinidad. Este último pertenece a la familia de receptores ß2 adrenérgicos que presentan siete dominios de intramembrana, e inician la activación a través de G proteínas específicas. De esta manera se desencadenan diversos pasos metabólicos a través de varias enzimas claves. La actividad de la fosfolipasa Cß (PLCß) origina dos segundos mensajeros: Inositol 3 fosfato (IP3) que promueve la movilización de calcio del sistema tubular denso al citosol y el diacilglicerol (DG) que activa proteína quinasa C (PKC). Si bien la plaqueta no prolifera se han detectado enzimas relacionadas a oncogenes. De esta manera se han estudiado y comprendido nuevos caminos de activación. La familia de la tirosina quinasas, relacionas a la proliferación celular y oncogenes, fosforilan residuos tirosinas; en su mayoría son quinasas del tipo no receptor que se encuentran en el citosol como ser: Scr, Syk y FAK. La fosfolipasa Cy necesita la presencia de RasGAP, Rap 1b para hidrolizar fosfoinosítidos de membrana. La formación de este complejo trimérico se induce por trombina. La fosfoinositol-3-quinasa fosforila la posición 3 del anillo del inositol generando nuevos compuestos. La regulación completa de estos mecanismos de activación llevan a la respuesta hemostática plaquetaria. Su conocimiento hace posible el desarrollo de moléculas inhibitorias como terapéutica en los procesos trombóticos y tromboembólicos

Rabies infection and specific effect of vaccination in mice selected for high and low immunobiological parameters

Innate and acquired resistance to rabies infection was investigated in mice genetically selected for high(H) or low(L) antibody responsiveness from selections I, III and IV and in mice selected for maximal (AIRmax) or minimal (AIRmin) acute inflammatory reaction. These mouse lines were infected intramuscularly with different virus dilutions and the LD50 was determined. The HIII and HIV mouse lines were more susceptible than the LIII and LIV lines and the HI line showed a discrete but higher resistance than the LI line. Analysis of the interline (H x L) F1 hybrids from selections III and IV indicated different dominance effects on the "resistant" and "susceptible" phenotypes when the route of vaccination was changed. No differences were observed between the AIRmax and AIRmin mice, suggesting that inflammation plays a minor role in the resistance to rabies virus. The comparison of LD50 in mice vaccinated by distinct routes showed that the highest interline difference occurred after intramuscular vaccination (250-fold between H and L and 800-fold between F1 and L). These results indicate that different mechanisms may participate in acquired antirabies resistance.

Clearance-inducing antibodies are responsible for protection against the acute phase of Trypanosoma cruzi infection in mice

A study was conducted on mice infected with strains Y and CL of Trypanosoma cruzi. The ability of anti-Y and anti-CL sera to induce complement-mediated lysis, immune clearance and protection against the acute phase of the infection was studied using homologous anti-Y or anti-CL serum tested with the Y or CL strain, or heterologous anti-Y serum tested with the CL strain or anti-CL serum tested with the Y strain. Complement-mediated lysis was induced by both homologous and heterologous antisera but protection was afforded only by homologous antisera. Immune clearance was induced by homologous but not by heterologous antisera. Antisera with high clearance ability were able to confer protection whereas antisera with high lytic ability were not. These results show a high correlation between the antibody ability to induce clearance and to confer protection and suggest that clearance rather than lysis is responsible for protection against the acute phase of the infection. The mechanisms of antibody protection against the acute phase of the infection is discussed.

Incidence of Rh immunization between 1981 and 1992.

BACKGROUND. The Institute of Immunohaematology has had an Rh clinic at the Nowrosjee Wadia Maternity Hospital since 1957. Between then and 1977, 5% Rh-negative women produced Rh antibodies. Between 1978 and 1980, the rate of immunization was reduced to 3.3%. In the present study we determined the incidence of Rh immunization between 1981 and 1992. METHODS. ABO and Rh grouping was carried out by standard methods on 139,635 samples collected from antenatal women. Six thousand nine hundred and fourteen (5%) Rh-negative women were screened for Rh antibodies using an enzyme technique. Analysis was carried out by dividing the data into four groups, each of three years duration. RESULTS. The number of women attending the antenatal outpatients increased steadily but the frequency of Rh-negativity remained at approximately 5%. The rate of Rh immunization among Rh-negative women declined from 3.1% during 1981-83 to 1.7% during 1990-92. The rate among pregnant women dropped from 0.16% to 0.09% and this was statistically significant (p < 0.05). The incidence of Rh immunization among Rh-negative women increased from 0.4% in the first pregnancy to 17.5% after four or more pregnancies (p < 0.01). Only 15 out of 167 Rh immunized women had received anti-D immunoglobulin previously. CONCLUSIONS. The incidence of Rh immunization has declined during the last 12 years possibly due to family planning and extensive use of anti-D immunoglobulin. However, complete eradication of Rh haemolytic disease of the newborn will be possible only if a comprehensive Rh prophylaxis programme is instituted.