Natural Killer (NK) cells can engage multiple virally infected or tumor cells sequentially and deliver perforin for cytolytic killing of these targets. Using microscopy to visualize degranulation ...from individual NK cells, we found that repeated activation via the Fc receptor CD16 decreased the amount of perforin secreted. However, perforin secretion was restored upon subsequent activation via a different activating receptor, NKG2D. Repeated stimulation via NKG2D also decreased perforin secretion, but this was not rescued by stimulation via CD16. These different outcomes of sequential stimulation could be accounted for by shedding of CD16 being triggered by cellular activation. The use of pharmacological inhibitors and NK cells transfected to express a noncleavable form of CD16 revealed that CD16 shedding also increased NK cell motility and facilitated detachment of NK cells from target cells. Disassembly of the immune synapse caused by CD16 shedding aided NK cell survival and boosted serial engagement of target cells. Thus, counterintuitively, shedding of CD16 may positively impact immune responses.
Trichlorfon is a widely used drug to control ectoparasites in fish farming and is effective in treating protozoa, helminths, and crustaceans. However, prior to a concentration recommendation made for ...therapeutic purposes in aquaculture, it is necessary to establish its toxicity, behavioural and histological effects, and determine a safe use dose for each target species. Here we investigated the acute toxicity (LC50-12 h) of trichlorfon and its behavioural and histological effects on arapaima (Arapaima gigas) larvae and juveniles. For the acute toxicity tests (LC50), arapaima larvae and juveniles were exposed at 0, 50, 250, 500, 750, 1.000 and 1.250 mg L−1 of trichlorfon for 12 h. During this period, behavioural changes, mortality, and the water physico-chemical parameters were recorded. Immediately after a toxicity test, gills were collected for the histological analysis. The LC50–12 h for the arapaima larvae and juveniles were 411.8 mg L−1 and 587.3 mg L−1, respectively. The fish exposed for different times to the 250, 500, 750, 1.000 and 1.250 mg L−1 concentrations showed a dose-dependent effect with behavioural changes, such as erratic swimming, loss of balance, lethargy, gasping at the water surface and muscle spasms. Histological changes, such as lamellar hyperplasia and cell hypertrophy, total lamellar fusion, dilation, and vascular congestion in the central filament vessel, interlamellar hyperplasia, capillary congestion, proliferation of mucous cells, dilation of the venous sinus and capillaries, leukocyte infiltrate and haemorrhage, were observed and ranged from mild to diffuse lesions. However, branchial necrosis was presented only in the fish exposed to ≥ 500 mg L−1 of trichlorfon. In conclusion, sublethal trichlorfon concentrations (≤ 250 mg L−1) and short exposure times (up to 180 min) can be safely used in arapaima larvae and juveniles because they do not alter their normal behaviour nor induce mortalities and/or irreversible injuries to their gills.
•Trichlorfon LC50–12h of larvae/juveniles were respectively 411.8 and 587.3 mg L−1.•Trichlorfon was classified as non-toxic for arapaima.•The behavioural changes in the trichlorfon-exposed arapaima were dose-dependent.•Trichlorfon at ≥ 500 mg L−1 caused moderate to severe harm to arapaima gills.•The 50 and 250 mg L−1 trichlorfon concentrations were safe for arapaima.
MUCORMICOSE: RELATO DE CASO EM MENOR DE IDADE IMUNOCOMPETENTE Cruz dos Santos, Raísa Lamara; Maia, Naiara Chaves; Barreto, Juliana Li Ting Matos Sun ...
The Brazilian journal of infectious diseases,
January 2022, 2022-01-01, Letnik:
26
Journal Article
Recenzirano
Odprti dostop
a Mucormicose é uma infecção fúngica extremamente rara e grave, causada por fungos da ordem Mucorales, a qual pode ser classificada em 6 categorias: cutânea, rinocerebral, pulmonar, gastrointestinal, ...disseminada e formas raras incomuns. A manifestação clínica imediata varia de acordo com a topografia e o seu diagnóstico frequentemente é atrasado devido a inespecificidade dos sintomas, sendo os exames padrão-ouro para o diagnóstico a biópsia e a avaliação histopatológica dos tecidos infectados. Em relação ao tratamento, este pode ser feito cirurgicamente pelo desbridamento da lesão, ou por meio de antifúngicos, na qual a Anfotericina B com formulação lipídica é o medicamento de primeira escolha.
Paciente pediátrico do sexo masculino, 10 meses de vida, sem diagnóstico de doenças prévias e com RT-PCR negativo para COVID-19, apresentando lesão aparentemente infiltrativa em face há 4 meses. Foi transferido de hospital oncológico infantil para o Hospital Universitário João de Barros Barreto, referência no tratamento de doenças infecciosas, após a biópsia descartar neoplasia maligna e sugerir infecção fúngica. Neste hospital, o paciente foi admitido acompanhado da mãe, em bom estado geral, sem queixas clínicas, apresentando os resultados diagnósticos do histopatológico e da tomografia computadorizada dos seios da face, os quais demonstraram lesão expansiva, heterogênea e infiltrativa no tecido subcutâneo, compreendendo a área ocular, interocular frontal e nasomalar direita, com inflamação crônica apontando granuloma, necrose e estruturas fúngicas sugestivas de mucormicose. Em sua admissão, realizou exames laboratoriais, os quais apresentaram discreta anemia, microcitose, anisocitose e leucocitose, além de função renal e hepática preservadas e ionograma sem alterações significativas. Iniciou antibioticoterapia no primeiro hospital e deu prosseguimento com Anfotericina B Complexo Lipídico após transferência para o tratamento da mucormicose. Ao finalizar o processo terapêutico, obteve alta hospitalar, na qual a mãe foi instruída a realizar hidratação da pele do bebê, e orientada acerca do tratamento para a anemia e da necessidade de acompanhamento com imunologista.
Ante o exposto, é imperioso que o diagnóstico seja feito precocemente, para que o manejo da infecção seja o menos traumático e com a menor quantidade de sequelas possíveis para o paciente.
TIGIT is an inhibitory receptor expressed on lymphocytes and can inhibit T cells by preventing CD226 co-stimulation through interactions in cis or through competition of shared ligands. Whether TIGIT ...directly delivers cell-intrinsic inhibitory signals in T cells remains unclear. Here we show, by analysing lymphocytes from matched human tumour and peripheral blood samples, that TIGIT and CD226 co-expression is rare on tumour-infiltrating lymphocytes. Using super-resolution microscopy and other techniques, we demonstrate that ligation with CD155 causes TIGIT to reorganise into dense nanoclusters, which coalesce with T cell receptor (TCR)-rich clusters at immune synapses. Functionally, this reduces cytokine secretion in a manner dependent on TIGIT's intracellular ITT-like signalling motif. Thus, we provide evidence that TIGIT directly inhibits lymphocyte activation, acting independently of CD226, requiring intracellular signalling that is proximal to the TCR. Within the subset of tumours where TIGIT-expressing cells do not commonly co-express CD226, this will likely be the dominant mechanism of action.
MENINGITE EOSINOFÍLICA POR ANGIOSTRONGYLUS: RELATO DE CASO dos Santos, Raísa Lamara Cruz; Maia, Naiara Chaves; Barreto, Juliana Li Ting Matos Sun ...
The Brazilian journal of infectious diseases,
January 2022, 2022-01-01, Letnik:
26
Journal Article
Recenzirano
Odprti dostop
A meningite eosinofílica é definida como a presença de mais de 10 eosinófilos/mm3 no líquido cefalorraquidiano e/ou eosinófilos compondo mais de 10% dos leucócitos totais. A eosinofilia no líquor se ...associa a um número limitado de doenças, principalmente infecções parasitárias, como a meningite causada pelo Angiostrongylus cantonensis, um parasita endêmico em diversas partes do mundo. O quadro clínico neurológico em geral apresenta rigidez nucal, náuseas, vômitos e cefaléia. O tratamento é realizado com medidas de suporte e corticoterapia, e a doença costuma ter curso autolimitado.
Criança de 11 meses, sexo feminino, com história de tosse produtiva e quadros febris por 15 dias, responsável refere episódio de ingesta de fezes de coelho, foi encaminhada para o Hospital Universitário João de Barros Barreto, após a administração de antibioticoterapia prescrita em Unidade de Pronto Atendimento ser ineficaz. Em sua admissão, a paciente estava hipoativa, com febre, irritabilidade e tosse produtiva esporádica, com leucocitose importante nos exames laboratoriais, obtendo hipótese diagnóstica de pneumonia e iniciando a conduta terapêutica com Ceftriaxona endovenosa, trocada por Cefepime em seguida. Após 3 dias de manutenção do quadro clínico, realizou-se o exame do líquido cefalorraquidiano, o qual apresentou aspecto turvo, cor clara, citometria com 750 células/mm³, predomínio de eosinófilos (50%) e ausência de bactérias, e o exame parasitológico de fezes, referindo ausência de helmintos e protozoários. Assim, foi estabelecido diagnóstico de Meningite Eosinofílica, e se acrescentou Dexametasona e Albendazol à terapêutica. No sexto dia de internação, um novo exame de punção lombar demonstrou um líquor incolor e límpido, com 95 células/mm³ e eosinófilos em 25%. No mesmo dia, a paciente cursou com convulsão, bradicardia e estado comatoso, sendo transferida para a unidade de terapia intensiva para estabilização hemodinâmica, e foi inserida sonda nasogástrica e suspenso o Albendazol. Além disso, o líquor foi enviado para análise através de imunoensaio para detecção de Angiostrongylus cantonensis, sendo o resultado positivo, foi dado início ao processo de transferência para hospital de referência a atenção pediátrica.
Isto posto, é primordial uma anamnese criteriosa acerca dos sinais e sintomas e avaliar a presença de vetores no convívio do paciente para aliar à análise do exame do líquor para definir o diagnóstico e conduta.
One mechanism by which monoclonal antibodies (mAb) help treat cancer or autoimmune disease is through triggering antibody-dependent cellular cytotoxicity (ADCC)
CD16 on Natural Killer (NK) cells. ...Afucosylation is known to increase the affinity of mAbs for CD16 on NK cells and here, we set out to assess how mAb afucosylation affects the dynamics of NK cell interactions, receptor expression and effector functions. An IgG1 version of a clinically important anti-CD20 mAb was compared to its afucosylated counterpart (anti-CD20-AF). Opsonization of CD20-expressing target cells, 721.221 or Daudi, with anti-CD20-AF increased NK cell cytotoxicity and IFNγ secretion, compared to anti-CD20. The afucosylated mAb also caused a more rapid and greater loss of CD16 from NK cell surfaces. Loss of CD16 has recently been shown to be important for NK cell detachment and sequential engagement of multiple target cells. Here, live-cell time-lapse microscopy of individual cell-cell interactions in an aqueous environment and a three-dimensional matrix, revealed that anti-CD20-AF induced more rapid killing of opsonized target cells. In addition, NK cells detached more quickly from target cells opsonized with anti-CD20-AF compared to anti-CD20, which increased engagement of multiple targets and enabled a greater proportion of NK cells to perform serial killing. Inhibition of CD16 shedding with TAPI-0 led to reduced detachment and serial killing. Thus, disassembly of the immune synapse caused by loss of cell surface CD16 is a factor determining the efficiency of ADCC and antibody afucosylation alters the dynamics of intercellular interactions to boost serial killing.
Whole genome sequencing of bovine breeds has allowed identification of genetic variants in milk protein genes. However, functional repercussion of such variants at a molecular level has seldom been ...investigated. Here, the results of a multistep Bioinformatic analysis for functional characterization of recently identified genetic variants in Brazilian Gyr and Guzerat breeds is described, including predicted effects on the following: (i) evolutionary conserved nucleotide positions/regions; (ii) protein function, stability, and interactions; (iii) splicing, branching, and miRNA binding sites; (iv) promoters and transcription factor binding sites; and (v) collocation with QTL. Seventy-one genetic variants were identified in the caseins (
CSN1S1
,
CSN2
,
CSN1S2
, and
CSN3
),
LALBA
,
LGB
, and
LTF
genes. Eleven potentially regulatory variants and two missense mutations were identified. LALBA Ile60Val was predicted to affect protein stability and flexibility, by reducing the number the disulfide bonds established. LTF Thr546Asn is predicted to generate steric clashes, which could mildly affect iron coordination. In addition, LALBA Ile60Val and LTF Thr546Asn affect exonic splicing enhancers and silencers. Consequently, both mutations have the potential of affecting immune response at individual level, not only in the mammary gland. Although laborious, this multistep procedure for classifying variants allowed the identification of potentially functional variants for milk protein genes.
This study aims to describe the eligibility for biologic therapies for severe asthma (SA) in a cohort of patients attending the Program for Control of Asthma (ProAR) in Bahia, Brazil.
Data from SA ...patients (≥18 years old) attending the ProAR, that were included in a case-control study conducted from 2013 to 2015, were used to reassess patients according to a modified ERS/ATS 2014 SA criteria. Patients were then classified according to the eligibility for SA biological therapy based on current prescription labels.
From 544 patients in the cohort, 531 (97.6%) were included and 172 (32.4%) were identified as SA patients according to the ERS/ATS 2014 modified criteria. Of these 172 patients, 69 (40.1%) were ineligible for any of the biologicals approved for asthma (omalizumab, mepolizumab, reslizumab and benralizumab), 60 (34.9%) patients were eligible for one of the biological therapies, and 10 (5.8%) patients were eligible for all biological therapies.
More than half of patients with SA were eligible for biologic therapy in our study, but none of them received this form of treatment. Almost half of them were not eligible to any of the approved biologics, however. The variability and overlap in patients' eligibility highlight the importance of evaluating each patient individually for a more personalized treatment approach. While there is a need to increase access for some of those eligible that may really need a biologic treatment, continuous efforts are required to develop alternatives to those who are not eligible.
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