Covid-19 ­ testes de antígeno / Covid-19 - antigen tests

Em janeiro de 2020, os testes para detectar o SARS-CoV-2 em amostras coletadas de pacientes foram desenvolvidos logo após o sequenciamento e divulgação do genoma do vírus (CORMAN et al., 2020) e, desde então, diferentes metodologias de testagem , têm sido empregadas em contextos distintos. Embora sejam o padrão de referência para diagnóstico da infecção aguda pelo SARS-CoV-2, os testes moleculares de reação em cadeia da polimerase (RT-PCR) não podem ser dimensionados para atender às demandas extensas da saúde pública (MINA & ANDERSEN, 2021). O processo é limitado para algumas regiões devido à necessidade de equipamentos sofisticados, operadores extremamente qualificados ao tempo que pode decorrer. Contudo, os testes de antígeno, permitem limitar de forma eficaz a disseminação da COVID-19 e responder a surtos da pandemia. Foram levantadas no estudo as recomendações quanto aos testes de antígeno emitidos pela Organização Mundial da Saúde (OMS), pela Europa, pelo Reino Unido, Estados Unidos, Israel e Brasil.

In January 2020, tests to detect SARS-CoV-2 in samples collected from patients were developed soon after the sequencing and dissemination of the virus genome (CORMAN et al., 2020) and, since then, different testing methodologies, have been used in different contexts. Although they are the reference standard for diagnosing acute SARS-CoV-2 infection, molecular polymerase chain reaction (RT-PCR) tests cannot be scaled to meet the extensive demands of public health (MINA & ANDERSEN, 2021 ). The process is limited to some regions due to the need for sophisticated equipment, extremely qualified operators and the time that may elapse. However, antigen tests effectively limit the spread of COVID-19 and respond to pandemic outbreaks. Recommendations for antigen tests issued by the World Health Organization (WHO), Europe, the United Kingdom, the United States, Israel and Brazil were raised in the study.

Frequência dos antígenos eritrocitários do sistema AB em felinos domésticos no estado da Paraíba / Frequency of AB blood System in domestic cats of Paraíba, Brazil

Objetivou-se com este estudo determinar a frequência de antígenos eritrocitários do sistema AB em felinos domésticos da Paraíba, Brasil. Foram selecionados aleatoriamente 178 gatos, clinicamente saudáveis, sem pré-requisitos quanto a sexo ou raça, com peso corporal acima de 1,5 kg e faixa etária acima de um ano de idade, abordados no ato da consulta ambulatorial em clínicas médicas de pequenos animais distribuídas entre três cidades da Paraíba (João Pessoa, Campina Grande e Patos). A determinação dos tipos sanguíneos foi realizada através do teste de hemaglutinação em tubo de ensaio e, a tipagem reversa foi realizada para as amostras tipos B e AB para confirmação e evidenciação de aloanticorpos naturais. Neste estudo a frequência relativa de antígenos eritrocitários A, B e AB em sua totalidade para felinos sem raça foram 98,1%, 1,21% e 0,69%, respectivamente. Todos os felinos com definição racial foram do tipo sanguíneo A. Diante destes, a probabilidade de ocorrência de reações transfusionais aleatórias obtidas foi de 2,78%, sendo cerca 40% (1,11%) potencialmente fatais. Desta forma, dado o conhecimento da frequência dos diferentes tipos sanguíneos em felinos, de uma determinada região, conclui-se que a tipagem sanguínea e o teste de compatibilidade, são importantes ferramentas que permitem ao médico veterinário tomar medidas preventivas que minimizem riscos de ocorrência de reações transfusionais e isoeletrólise neonatal e, estabelece pré-requisitos a respeito dos riscos de procedimentos hemoterápicos em felinos que circunstancialmente necessitem serem conduzidos de forma aleatória.

The objective of this study was to determine the frequency of the AB blood group antigens system in domestic cats of Paraíba, Brazil. We randomly selected 178 cats which were clinically healthy, with no prerequisites in terms of gender or race, weighing above 1.5 kg, and were over one year of age. These cats were randomly selected when they entered the small animal clinic facilities in the cities of João Pessoa, Campina Grande and Patos. The determination of blood types was made using the hemagglutination test tube, and the reverse typing was performed for samples B and AB types and for confirmation of alloantibodies natural disclosure. In this study the relative frequency of A, B and AB blood group antigens in cats without a determined breed was 98.1%, 1.21% and 0.69% respectively. All cats with breed definition were blood type A. The likelihood of random transfusion reactions was 2.78%, approximately 40% (1.11%) potentially fatal. Thus, given knowledge of the frequency of different blood types in cats, from a given region, it is concluded that blood typing and compatibility test are important tools that enable the veterinarian to take preventative measures to minimize risks of isoelectrolisys reactions and neonatal transfusion, and establishes prerequisites about the risks of hemotherapic procedures in cats that require circumstantially to be conducted randomly.

Nanoparticles and microparticles of polymers and polysaccharides to administer fish vaccines

Aquaculture has become an important economic sector worldwide, but is faced with an ongoing threat from infectious diseases. Vaccination plays a critical role in protecting commercially raised fish from bacterial, viral and parasitic diseases. However, the production of effective vaccines is limited by the scarcity of knowledge about the immune system of fish. Improving vaccines implies using antigens, adjuvants and employing methods of administration that are more effective and less harmful to the fish. In this context, in recent year there have studies of methods of encapsulating antigens in matrices of different types to apply in fish vaccines. This work reviews the new methods to improve fish vaccines by encapsulating them in polymers and polysaccharides.

Improving vaccines by targeting antigens to dendritic cells

A new approach to enhancing the effectiveness of vaccines is to deliver antigens selectively to dendritic cells (DC) in situ, via monoclonal antibodies specific for particular DC surface molecules. This can markedly enhance CTL responses and, via helper T cells, also enhance antibody responses. DC activation agents or adjuvants must also be administered for effective CTL responses, but in some cases good antibody responses can be obtained without adjuvants. Here we review the role of different DC subsets and different DC target molecules in obtaining enhanced immune responses.

Improving vaccines by targeting antigens to dendritic cells

A new approach to enhancing the effectiveness of vaccines is to deliver antigens selectively to dendritic cells (DC) in situ, via monoclonal antibodies specific for particular DC surface molecules. This can markedly enhance CTL responses and, via helper T cells, also enhance antibody responses. DC activation agents or adjuvants must also be administered for effective CTL responses, but in some cases good antibody responses can be obtained without adjuvants. Here we review the role of different DC subsets and different DC target molecules in obtaining enhanced immune responses.

Inquérito sorológico da brucelose canina através da utilização de antígeno externo e interno de Brucella canis e Brucella ovis / Serodiagnosis of canine brucellosis using external and internal antigens of Brucella canis and Brucella ovis

O objetivo desse estudo foi investigar a ocorrência da brucelose canina na cidade do Rio de Janeiro utilizando-se a técnica deimunodifusão em gel de agarose.Antígenos externo e interno de Brucella canis e Brucella ovis foram previamente preparadose um antígeno comercial usado para diagnóstico da brucelose canina foi também utilizado.Amostras de soro de 316 cãescoletadas aleatoriamente foram examinadas.Oito amostras (2,53 por cento) foram positivas no teste utilizando-se antígeno externo deB. canis e B. ovis e sete amostras (2,2 por cento) foram confirmadas com o antígeno comercial.Três amostras (0,95 por cento) foram positivaspara todos os antígenos testados. Antígenos externo e interno devem ser usados nos testes sorológicos para diagnóstico dabrucelose canina para detecção precoce e obtenção de resultados mais precisos, respectivamente.

The present study was designed to carry out a serologic investigation of canine brucellosis by using agar gel immunodiffusiontest in the Rio de Janeiro city. External and internal antigens of B. canis and B. ovis were previously prepared and a commercialkit used for canine brucellosis diagnosis, was also employed. Random samples of 316 dogs were examined. Eight samples (2,53 percent) were positive by using external antigen of B. canis and B. ovis. Seven samples (2,2 percent) were positive using the commercialantigen also, and three samples (0,95 percent) were positive for all the antigens employed. External and internal antigens must beused for early detection and accurate results, respectively.

La modulación del sistema inmune de mucosas con polisacáridos: Bases para una atractiva alternativa en terapia / Modulation of the mucosal immune system with polysaccharides: Basis for an attractive therapeutic alternative

El sistema inmune de mucosas del intestino presenta propiedades únicas: está expuesto a una gran variedad y cantidad de antígenos, desarrolla una actividad inmunológica permanente y mantiene un microambiente fisiológicamente desviado hacia respuestas anti-inflamatorias. Es capaz de distinguir y neutralizar agentes nocivos y reconocer antígenos inocuos, generando entonces un estado de no respuesta llamado tolerancia oral. Este fenómeno natural representa una forma fisiológica, segura e inocua de manipular las respuestas inmunes, para el tratamiento de enfermedades autoinmunes, inflamatorias o alérgicas. Aquellos compuestos que presenten la habilidad de favorecer la tolerancia permitirían optimizar el desarrollo de nuevos protocolos de inmunointervención. Quitosano (Q) es un polisacárido que abunda en la naturaleza con características fisicoquímicas y biológicas particulares: carece de toxicidad y alergenicidad, es biocompatible y biodegradable, presenta propiedades mucoadhesivas que favorecen el transporte y la absorción de proteínas a través del epitelio. Tiene actividad adyuvante, aumentando los niveles de IgA en la mucosa. Estas características lo convierten en un candidato ideal para la inmunointervención a nivel de mucosas. En este trabajo se describe el mecanismo de acción del Q luego de la administración oral, demostrando por primera vez que Q contribuye a mantener la homeostasis intestinal y a modular a nivel local y sistémico las respuestas inmunes hacia un antígeno proteico. Esta caracterización ayuda a comprender cómo participa un polisacárido en la fina regulación de las respuestas de mucosa y sugiere alternativas de manipulación que permitirán el desarrollo de terapias que requieran de microambientes anti-inflamatorios.

The mucosal immune system exhibits distinctive traits: it is permanently exposed to an overwhelming amount and variety of antigens; it maintains a continuous immune activity and it sustains a physiological environment biased to anti-inflammatory responses. Although it mounts efficient responses against pathogens, it reacts to innocuous antigens developing the oral tolerance state. Oral tolerance is a natural process that can be safely applied for the treatment of autoimmune, inflammatory or allergic diseases. Compounds able to promote the tolerance phenomenon can be used to optimize the development of alternative therapies. Chitosan (Q) is a natural and abundant polysaccharide with singular biological and physico-chemical properties that make it a good candidate to modulate the mucosal immunity: non toxic, biocompatible and biodegradable, strongly mucoadhesive favoring the transepithelial absorption of proteins and adjuvant, enhancing the levels of IgA to co-administered antigens. This work describes the Q activity mechanism early after its oral administration, for the first time showing, Q´s contribution to the intestinal homeostasis and also its modulation of the immune response to a protein antigen at local and systemic level. These studies will help understand how the intestinal regulatory activity occurs, and develop new therapeutic approaches to stimulate anti-inflammatory environments at mucosal level.

An experimental design for induction of non-specific aortoarteritis.

BACKGROUND: An attempt was made to induce aortoarteritis in mice by using various antigens. METHODS AND RESULTS: The Swiss mice were immunized with eight different antigens and were grouped A to G. Group H served as control. The mice were then bled at 1st, 2nd, 4th, 6th and 8th month interval post-immunization for estimating antibody titer. Then the mice were sacrificed and the heart, aorta and kidney were taken out and processed for hematoxylin-eosin staining. There was gradual increase in the antibody titer from 1st month till 4th month within all the experimental groups (A-G), when compared with control group H. The titer started falling sharply from 6th month post-immunization. However, the control group H did not show much variation. When each individual group was compared separately with control group H, the significant statistical value was obtained. Histopathological examination revealed mild inflammation (+) in kidney by 2nd month, moderate inflammation (++) by 6th month, extensive inflammation (+++) by 8th month and alteration in the normal parenchyma of kidney by 8th month. CONCLUSIONS: The histopathological changes brought out through antigens were more pronounced by 8th month following injection of tunica media, tunica adventitia, tunica intima and aorta collagen as compared to that of standard collagen and mouse aorta injections.

Bronchodilatory and anti-allergic effect of PulmoFlex--a proprietary herbal formulation.

PulmoFlex, a poly-herbal anti-asthmatic formulation has been reported to possess antihistaminic, mast cell stabilizing, anti-anaphylactic and antiallergic properties in experimental animals and clinical trials. The present study was undertaken to determine the effect of PulmoFlex on isolated perfused rat lung. The lung tissues were perfused at a pressure of 50 mmHg using oxygenated Krebs solution at 37 degrees C. PulmoFlex (1 & 2 mg/ml) increased the pulmonary perfusion flow indicating its bronchodilatory action. PulmoFlex (500 mcg) significantly prevented histamine (50 mcg), acetylcholine (50 mcg) and C-48/80 (10 mcg), induced bronchoconstriction indicating its antihistaminic, anticholinergic and mast cell stabilizing actions on pulmonary vascular beds and bronchioles, respectively. Lung tissue of sensitized (BSA) rats treated with PulmoFlex (20 mg/kg x 10 days) showed better perfusion following Ex vivo antigenic challenge as compared to untreated rats. This indicates the possibility of suppression of IgE mediated immune reaction by PulmoFlex. Thus, the present findings, suggest that PulmoFlex acts as an antiasthmatic by its bronchodilatory, membrane stabilizing, antihistaminic, anticholinergic and immunomodulatory (reaginic antibody mediated) effects.

Immunization of cattle against Hyalomma anatolicum anatolicum using larval antigens.

Development of immunity in cross-bred (Bos taurus x Bos indicus) calves against Hyalomma anatolicum anatolicum, vector of bovine tropical theileriosis, was studied using larval antigen (LS) in Freund's complete adjuvant (FCA). Calves immunized with LS + FCA showed significant rejection of larvae (57.25 +/- 6.8) and nymphs (45.75 +/- 5.16). Abnormally fed larvae (11.4 +/- 0.8) and nymphs (8.25 +/- 1.2) were also recovered from immunized calves. This abnormal feeding may possibly be attributed to their inability to gain access to the blood vessels owing to the host immunological reactions. Consequently, feeding of extravascular fluid leads to white colour of fed ticks. Sera from all immunized calves after a week of immunization were positive for anti-LS antibodies in ELISA. The investigation indicates that LS in FCA enhanced anti-tick immunity.

Immunization of rabbits against Hyalomma anatolicum anatolicum using homogenates from unfed immature ticks.

Antigens were prepared from unfed larvae and nymphs of H. a. anatolicum as homogenised antigens (HLAg and HNAg, respectively). Five rabbits each were inoculated, s.c. with 8.56 mg HLAg and 9.34 mg HNAg in 3 divided doses. Following immunisation rabbits developed significant level of protective immunity to infestation with adults of this species. Significant reduction in engorged percentage and weights of engorged females and egg masses were observed in females fed on immunized rabbits, compared to that of female ticks fed on control rabbits. The engorgement period was also increased significantly. However, conversion efficiency indices remained unaffected. Larval antigen immunized rabbits showed significant antibody level from 28-126 days while with HNAg elevated antibody levels were recorded up to 112 days. Further, the rabbits immunized with HLAg had elevated level of antibodies against HLAg, HNAg, and adult antigen in ELISA. But HNAg immunized rabbits had lower levels of antibodies against HLAg and HAAg as compared to values recorded against HNAg. Anti-HLAg and anti-HNAg sera recognised common antigenic bands of 97.4, 85, 66, 47.3, 42 and 31 kDa in homogenates of larvae, nymphs and adults.

immunogenic effect of purified antigens of B Alexandrina against S Mansoni in experimental animals [II] as measured by the histopathological changes in the liver

The objective of this work was to test the immunogenic effect of 2 purified non-infected B. alexandrina hepatopancreas through histopathological changes in liver of Swiss albino mice [15 - 20 g]. Gel filtration chromatography was used to fractionate the crude antigen into 5 fractions, followed by re-fractionation and determination of their molecular weights by sodium dodecyl sulfate polyacrylamide gel electrophoresis [SDS-PAGE]. Four dilutions of Fiv [20000 - 29000 daltons] and Fv [20000 - 240000 daltons] were injected in 2 groups of mice [33 each] at weekly intervals and another control group was injected with phosphate buffer saline [PBS] in the same manner. Sacrification was done at 7 weeks from infection with 100 S. mansoni cercariae through immersion method. The results revealed that there were marked histopathological changes in liver of the control group in comparison with the 2 vaccinated groups, which appeared more or less normal with slight inflammatory infiltrate

Determinación de la velocidad de tránsito intestinal en el ratón BALB/c / Determinaton of the velocity of intestinal transit in the BALB/c mouse

La determinación de la velocidad del tránsito intestinal en un modelo animal es de primordial importancia, sobre todo cuando se pretende utilizar la vía digestiva del mismo como sitio para la presentación de antígenos. En el presente trabajo se determinó la velocidad del tránsito intestinal en el ratón BALB/c, uno de los animales de laboratorio frecuentemente utilizado en la investigación de la respuesta inmune. Se administró un colorante vegetal por medio de una sonda orogástrica, a 45 ratones, mayores de 8 semanas de edad. Posteriormente se sacrificaron los animales a diferentes tiempos en un rango de 10 min a 24 h. El tracto intestinal se dividió de manera arbitraria, el intestino delgado en tres tercios y el intestino grueso, en dos partes. Las determinaciones mostraron que 25 min después de administrado el colorante, éste se localizó a nivel del primer tercio y en menor proporción, a nivel del segundo tercio del intestino delgado. A los 90 min, el colorante alcanzó la primera mitad del intestino grueso, y a las 2 h comenzó a ser eliminado en las heces. Sin embargo, 3 h después de la administración aún se encontró colorante en el estómago, con lo anterior se demostró que el colorante se emilinó de manera intermitente a partir del estómago hasta las 3 h. A las 10 h se encontró colorante en intestino grueso, pero no en intestino delgado ni en estómago, a las 24 h se había eliminado por completo. Se concluye que en el intestino, el tránsito del colorante es constante, aunque la liberación a partir del estómago es intermitente, y que la totalidad del proceso de tránsito intestinal se lleva a cabo antes de 24 h

Anticuerpos anti-VHC en insuficientes renales crónicos / Anti-HCV antibodies in patients with chronic renal failure

El virus de la hepatitis C es la principal causa de hepatitis post-transfusional en el mundo, pero poco se conoce acerca de la transmisión en los pacientes con insuficiencia renal crónica y en las unidades de hemodialisis. El presente trabajo estimó la prevalencia de los anticuerpos anti-VHC en los pacientes con insuficiencia renal crónica del Departamento de Nefrología del Hospital Universitario de los Andes, en Mérida Venezuela. Se admitieron 22 pacientes al estudio, todos con insuficiencia renal crónica. Los datos médicos referentes a factores de riesgo (trasnfuciones, drogadicción y promiscuidad sexual) fueron obtenidos de las historias clínicas y las encuestas aplicadas a los pacientes. Un ELISA anti-VHC de segunda generación fue usado como prueba serológica. De los 22 pacientes estudiados, 5 fueron anti-VHC positivos y 17 fueron negativos. Los 5 pacientes seropositivos eran hemodializados, lo cual arrojó una prevalencia del 22,7 por ciento en el grupo de estudio. Todos los pacientes insuficientes renales crónicos no hemodializados fueron anti-VHC (p= 0.0047). No hubo asociación significativa entre transfuciones y positividad al anti-VHC (p= 0.36). La hemodiálisis podría ser un factor de riesgo en la trasmisión del virus de la hepatitis C

Recrudescence induced by cyclophosphamide of chronic Trypanosoma cruzi infection in mice is influenced by the parasite strain

Reactivation of chronic chagasic patients may occur upon of use of immunosupressive drugs related to kidney or heart transplantation or when they are affected by concomitant HIV infection. This recrudescence, however, does not occur in all chagasic patients exposed to immunosuppressive agents. We therefore investigated the influence of Trypanosoma cruzi strains in the recrudescence of the parasitism in mice at the chronic phase treated with cyclophosphamide, an immunosuppressor that blocks lymphocytes DNA synthesis and therefore controls B cells response. A large variation was detected in the percentages of newly established acute phases in the groups of mice inoculated with the different strains. We suggest that reactivation of chronic T. cruzi infections is influenced by the parasite intrinsic characteristics, a phenomenon that might occur in the human disease.

Peripheral immune response in albino rats following cerebroventricular and intraperitoneal antigen challenge.

Success in neural tissue transplants at central nervous system suggest that the site may be immunologically privileged. However, this experimental study in which an antigen (Sheep Red Blood Cells) was administered into the third ventricle does not support the above concept. The antibody titre and soluble immune complex levels seen in these animals are similar to the levels seen in animals immunized with the same amount of antigen through the intraperitoneal route. Intraventricular immunization is rather a more potent modulator in decreasing the total WBC count (P < 0.05) and neutrophils (P < 0.001). Further a marked increase in lymphocytes (P < 0.01) in peripheral blood was observed in these animals. Intraventricular immunization also increased the killing power (NBT reduction) of the neutrophils (P < 0.05).

Implicancias de la evaluación inmunológica en el paciente oncológico quirúrgico / Implicances of the inmunologic evaluation in the surgery oncologic patient

El propósito de esta comunicación preliminar es evaluar la respuesta inmunológica del pacinete oncológico candidato a cirugía y sus implicancias en la morbimortalidad postoperatoria. Se analizan en forma prospectiva 27 pacientes portadores de neoplasia maligna(17 hombres y 10 mujeres) con una edad promedio de 64,4 años. La respuesta a los test cutáneos fue: 0 respuestas posistivas en 8 pacientes(29,6 por ciento ); 1 respuesta positiva en 9 pacientes(33,4 por ciento ); 2 respuestas positivas en 8 pacientes(29,6) y 3 o más respuestas positivas en 2 pacientes(7,4 por ciento ). La morbimortalidad postoperatoria se presentó exclusivamente en los pacientes anérgicos 3/14(21,4 por ciento ); en cambio, los pacientes con dos o más respuestas positivas, no presentaron morbimortalidad postoperatoria(p< 0,05). En el grupo de pacientes anérgicos 11 de 14 pacientes (78,6 por ciento ) fueron resecados versus el 100 por ciento de los pacientes con dos o más respuestas positivas(p< 0,05). En esta serie no se observaron diferencias estadistícamente significativas al correlacionar la respuesta inmunológica con los otros parámetros de evaluación nutricional

Inhibitory effects of cimetidine on graft survival of allotransplanted rats submitted to an active-passive enhancement protocol

The objetive of the presented study was to determine wheter cimetidine, a type-2 histamine receptor antagonist, inhibits the immunological enhancement of allografted rats achieved by treatment with donor antigen plus anti-donor antibody. Groups of rats submitted to this active-passive enhancement protocol and treated ip with 30 (APEC30; Group I; N = 4) or 60 (APEC 60; Group II; N = 8) mg/day cimetidine for 14 days had a significantly shorter graft survival (20.2 ñ 5.1 and 11.1 ñ 2.6 days, respectively) than the control group (animals submitted to the enhancement protocol and killed on day 72 after transplant when the graft was beating normally; APE; Group III; N = 6; P<0.05). On the other hand, these animals had a significantly longer graft survival than rats allotransplanted but not treated for enhancement (ALLO; Group V; N = 5; 8.2 ñ 0.8 days). The surgical control, consisting of isotransplanted animals, had a long-term survival (ISO; Group V; N = 6; rats killed 120 days after transplant with the graft beating normally). Animals treated with cimetidine, but not submitted to the enhancement protocol (AC 60; Group IV, N = 4) had a significantly shorter graft survival (6.25 ñ 0.5) than the allotransplanted animals (Group V). These results indicate inhibition of the suppressor mechanisms which participate in this type of immunological enhancement