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1.
J Exp Med ; 218(12)2021 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-34623376

RESUMO

Broadly protective vaccines against SARS-related coronaviruses that may cause future outbreaks are urgently needed. The SARS-CoV-2 spike receptor-binding domain (RBD) comprises two regions, the core-RBD and the receptor-binding motif (RBM); the former is structurally conserved between SARS-CoV-2 and SARS-CoV. Here, in order to elicit humoral responses to the more conserved core-RBD, we introduced N-linked glycans onto RBM surfaces of the SARS-CoV-2 RBD and used them as immunogens in a mouse model. We found that glycan addition elicited higher proportions of the core-RBD-specific germinal center (GC) B cells and antibody responses, thereby manifesting significant neutralizing activity for SARS-CoV, SARS-CoV-2, and the bat WIV1-CoV. These results have implications for the design of SARS-like virus vaccines.


Assuntos
Anticorpos Antivirais/imunologia , Anticorpos Amplamente Neutralizantes/imunologia , COVID-19/imunologia , Polissacarídeos/imunologia , Vírus da SARS/imunologia , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Motivos de Aminoácidos , Animais , COVID-19/genética , COVID-19/prevenção & controle , Vacinas contra COVID-19/genética , Vacinas contra COVID-19/imunologia , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Polissacarídeos/genética , Domínios Proteicos , Vírus da SARS/genética , SARS-CoV-2/genética , Glicoproteína da Espícula de Coronavírus/genética
2.
J Exp Med ; 218(12)2021 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-34647971

RESUMO

Adaptive immunity is a fundamental component in controlling COVID-19. In this process, follicular helper T (Tfh) cells are a subset of CD4+ T cells that mediate the production of protective antibodies; however, the SARS-CoV-2 epitopes activating Tfh cells are not well characterized. Here, we identified and crystallized TCRs of public circulating Tfh (cTfh) clonotypes that are expanded in patients who have recovered from mild symptoms. These public clonotypes recognized the SARS-CoV-2 spike (S) epitopes conserved across emerging variants. The epitope of the most prevalent cTfh clonotype, S864-882, was presented by multiple HLAs and activated T cells in most healthy donors, suggesting that this S region is a universal T cell epitope useful for booster antigen. SARS-CoV-2-specific public cTfh clonotypes also cross-reacted with specific commensal bacteria. In this study, we identified conserved SARS-CoV-2 S epitopes that activate public cTfh clonotypes associated with mild symptoms.

3.
Immunity ; 54(10): 2385-2398.e10, 2021 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-34508662

RESUMO

Potent neutralizing SARS-CoV-2 antibodies often target the spike protein receptor-binding site (RBS), but the variability of RBS epitopes hampers broad neutralization of multiple sarbecoviruses and drifted viruses. Here, using humanized mice, we identified an RBS antibody with a germline VH gene that potently neutralized SARS-related coronaviruses, including SARS-CoV and SARS-CoV-2 variants. X-ray crystallography revealed coordinated recognition by the heavy chain of non-RBS conserved sites and the light chain of RBS with a binding angle mimicking the angiotensin-converting enzyme 2 (ACE2) receptor. The minimum footprints in the hypervariable region of RBS contributed to the breadth of neutralization, which was enhanced by immunoglobulin G3 (IgG3) class switching. The coordinated binding resulted in broad neutralization of SARS-CoV and emerging SARS-CoV-2 variants of concern. Low-dose therapeutic antibody treatment in hamsters reduced the virus titers and morbidity during SARS-CoV-2 challenge. The structural basis for broad neutralizing activity may inform the design of a broad spectrum of therapeutics and vaccines.

4.
Immunity ; 54(8): 1841-1852.e4, 2021 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-34246326

RESUMO

Antibody titers against SARS-CoV-2 slowly wane over time. Here, we examined how time affects antibody potency. To assess the impact of antibody maturation on durable neutralizing activity against original SARS-CoV-2 and emerging variants of concern (VOCs), we analyzed receptor binding domain (RBD)-specific IgG antibodies in convalescent plasma taken 1-10 months after SARS-CoV-2 infection. Longitudinal evaluation of total RBD IgG and neutralizing antibody revealed declining total antibody titers but improved neutralization potency per antibody to original SARS-CoV-2, indicative of antibody response maturation. Neutralization assays with authentic viruses revealed that early antibodies capable of neutralizing original SARS-CoV-2 had limited reactivity toward B.1.351 (501Y.V2) and P.1 (501Y.V3) variants. Antibodies from late convalescents exhibited increased neutralization potency to VOCs, suggesting persistence of cross-neutralizing antibodies in plasma. Thus, maturation of the antibody response to SARS-CoV-2 potentiates cross-neutralizing ability to circulating variants, suggesting that declining antibody titers may not be indicative of declining protection.


Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , COVID-19/imunologia , COVID-19/virologia , SARS-CoV-2/imunologia , Anticorpos Monoclonais/imunologia , Especificidade de Anticorpos , COVID-19/epidemiologia , Humanos , Imunoglobulina G , Testes de Neutralização , SARS-CoV-2/genética , Carga Viral
5.
PLoS One ; 16(7): e0254640, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34255796

RESUMO

BACKGROUND: This study aimed to clarify how SARS-CoV-2 RNAemia is related to COVID-19 critical condition development and mortality in comparison with other predictive markers and scoring systems. METHODS: This is a retrospective cohort study conducted at Yokohama Municipal Citizen's Hospital and National Institute of Infectious Diseases. We recruited adult patients with COVID-19 admitted between March 2020 and January 2021. We compared RNAemia with clinical status on admission including scoring systems such as the 4C Mortality, CURB-65, and A-DROP, as well as the Ct value of the nasopharyngeal PCR, in predicting COVID-19 mortality and critical condition development. RESULTS: Of the 92 recruited patients (median age, 58; interquartile range, 45-71 years), 14 (14.9%) had RNAemia. These patients had an older age (median, 68 years vs. 55.5 years; p = 0.011), higher values of lactated dehydrogenase (median, 381 U/L vs. 256.5 U/L, p < 0.001), C-reactive protein (median, 10.9 mg/dL vs. 3.8 mg/dL; p < 0.001), D-dimer (median, 2.07 µg/mL vs. 1.28 µg/mL; p = 0.015), lower values of lymphocyte (median, 802/µL vs. 1007/µL, p = 0.025) and Ct of the nasopharyngeal PCR assay (median, 20.59 vs. 25.54; p = 0.021) than those without RNAemia. Univariate analysis showed RNAemia was associated with mortality (odds ratio [OR], 18.75; 95% confidence interval [CI], 3.92-89.76; area under the receiver operating characteristic curve [AUC], 0.7851; p = 0.002) and critical condition (OR, 72.00; 95% CI, 12.98-399.29; AUC, 0.8198; p < 0.001). Plus, multivariate analysis also revealed the association of RNAemia with critical condition (adjusted OR, 125.71; 95% CI, 11.47-1377.32; p < 0.001). CONCLUSION: On-admission SARS-CoV-2 RNAemia is a potent predictive marker of COVID-19 critical condition and mortality. The adjusted OR for critical condition was as high as 125.71.


Assuntos
Teste de Ácido Nucleico para COVID-19/normas , COVID-19/diagnóstico , RNA Viral/análise , Idoso , Biomarcadores/análise , COVID-19/mortalidade , Teste de Ácido Nucleico para COVID-19/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mucosa Nasal/virologia , Admissão do Paciente , Prognóstico , SARS-CoV-2/genética , SARS-CoV-2/isolamento & purificação , SARS-CoV-2/patogenicidade , Carga Viral
6.
Commun Biol ; 4(1): 820, 2021 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-34188173

RESUMO

Host lipid metabolism and viral responses are intimately connected. However, the process by which the acquired immune systems adapts lipid metabolism to meet demands, and whether or not the metabolic rewiring confers a selective advantage to host immunity, remains unclear. Here we show that viral infection attenuates the expression of genes related to lipid metabolism in murine CD4+ T cells, which in turn increases the expression of antiviral genes. Inhibition of the fatty acid synthesis pathway substantially increases the basal expression of antiviral genes via the spontaneous production of type I interferon (IFN). Using a combination of CRISPR/Cas9-mediated genome editing technology and a global lipidomics analysis, we found that the decrease in monounsaturated fatty acid caused by genetic deletion of Scd2 in mice was crucial for the induction of an antiviral response through activation of the cGAS-STING pathway. These findings demonstrate the important relationship between fatty acid biosynthesis and type I IFN responses that enhances the antiviral response.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Ácidos Graxos Monoinsaturados/metabolismo , Interferon Tipo I/farmacologia , Proteínas de Membrana/fisiologia , Nucleotidiltransferases/fisiologia , Estearoil-CoA Dessaturase/fisiologia , Viroses/imunologia , Animais , Interações Hospedeiro-Patógeno , Metabolismo dos Lipídeos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Transdução de Sinais , Viroses/metabolismo
7.
Nat Commun ; 12(1): 3789, 2021 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-34145279

RESUMO

Influenza viruses are a major public health problem. Vaccines are the best available countermeasure to induce effective immunity against infection with seasonal influenza viruses; however, the breadth of antibody responses in infection versus vaccination is quite different. Here, we show that nasal infection controls two sequential processes to induce neutralizing IgG antibodies recognizing the hemagglutinin (HA) of heterotypic strains. The first is viral replication in the lung, which facilitates exposure of shared epitopes that are otherwise hidden from the immune system. The second process is the germinal center (GC) response, in particular, IL-4 derived from follicular helper T cells has an essential role in the expansion of rare GC-B cells recognizing the shared epitopes. Therefore, the combination of exposure of the shared epitopes and efficient proliferation of GC-B cells is critical for generating broadly-protective antibodies. These observations provide insight into mechanisms promoting broad protection from virus infection.


Assuntos
Anticorpos Antivirais/imunologia , Linfócitos B/imunologia , Anticorpos Amplamente Neutralizantes/imunologia , Hemaglutininas Virais/imunologia , Interleucina-4/imunologia , Infecções por Orthomyxoviridae/imunologia , Animais , Anticorpos Antivirais/sangue , Anticorpos Amplamente Neutralizantes/sangue , Epitopos/imunologia , Feminino , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H2N2/imunologia , Vírus da Influenza A Subtipo H3N2/imunologia , Vacinas contra Influenza/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Transdução de Sinais/imunologia , Células T Auxiliares Foliculares/imunologia , Vacinação
8.
J Immunol ; 206(10): 2393-2401, 2021 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-33941657

RESUMO

Serological tests for detection of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Abs in blood are expected to identify individuals who have acquired immunity against SARS-CoV-2 and indication of seroprevalence of SARS-CoV-2 infection. Many serological tests have been developed to detect Abs against SARS-CoV-2. However, these tests have considerable variations in their specificity and sensitivity, and whether they can predict levels of neutralizing activity is yet to be determined. This study aimed to investigate the kinetics and neutralizing activity of various Ag-specific Ab isotypes against SARS-CoV-2 in serum of coronavirus disease 2019 (COVID-19) patients confirmed via PCR test. We developed IgG, IgM, and IgA measurement assays for each Ag, including receptor-binding domain (RBD) of spike (S) protein, S1 domain, full-length S protein, S trimer, and nucleocapsid (N) domain, based on ELISA. The assays of the S protein for all isotypes showed high specificity, whereas the assays for all isotypes against N protein showed lower specificity. The sensitivity of all Ag-specific Ab isotypes depended on the timing of the serum collection and all of them, except for IgM against N protein, reached more than 90% at 15-21 d postsymptom onset. The best correlation with virus-neutralizing activity was found for IgG against RBD, and levels of IgG against RBD in sera from four patients with severe COVID-19 increased concordantly with neutralizing activity. Our results provide valuable information regarding the selection of serological test for seroprevalence and vaccine evaluation studies.


Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Especificidade de Anticorpos , Antígenos Virais/imunologia , COVID-19/imunologia , Isotipos de Imunoglobulinas/imunologia , SARS-CoV-2/imunologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , COVID-19/diagnóstico , Teste de Ácido Nucleico para COVID-19 , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
9.
Front Immunol ; 12: 643040, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33790912

RESUMO

Humanized mouse models are attractive experimental models for analyzing the development and functions of human dendritic cells (DCs) in vivo. Although various types of DC subsets, including DC type 3 (DC3s), have been identified in humans, it remains unclear whether humanized mice can reproduce heterogeneous DC subsets. CD14, classically known as a monocyte/macrophage marker, is reported as an indicator of DC3s. We previously observed that some CD14+ myeloid cells expressed CD1c, a pan marker for bona fide conventional DC2 (cDC2s), in humanized mouse models in which human FLT3L and GM-CSF genes were transiently expressed using in vivo transfection (IVT). Here, we aimed to elucidate the identity of CD14+CD1c+ DC-like cells in humanized mouse models. We found that CD14+CD1c+ cells were phenotypically different from cDC2s; CD14+CD1c+ cells expressed CD163 but not CD5, whereas cDC2s expressed CD5 but not CD163. Furthermore, CD14+CD1c+ cells primed and polarized naïve CD4+ T cells toward IFN-γ+ Th1 cells more profoundly than cDC2s. Transcriptional analysis revealed that CD14+CD1c+ cells expressed several DC3-specific transcripts, such as CD163, S100A8, and S100A9, and were clearly segregated from cDC2s and monocytes. When lipopolysaccharide was administered to the humanized mice, the frequency of CD14+CD1c+ cells producing IL-6 and TNF-α was elevated, indicating a pro-inflammatory signature. Thus, humanized mice are able to sustain development of functional CD14+CD1c+ DCs, which are equivalent to DC3 subset observed in humans, and they could be useful for analyzing the development and function of DC3s in vivo.


Assuntos
Células Dendríticas/classificação , Células Dendríticas/imunologia , Receptores de Lipopolissacarídeos/análise , Animais , Antígenos CD1/análise , Linfócitos T CD4-Positivos/imunologia , Perfilação da Expressão Gênica , Glicoproteínas/análise , Humanos , Mediadores da Inflamação/análise , Camundongos
10.
HLA ; 98(1): 37-42, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33734601

RESUMO

HLA-A, -C, -B, and -DRB1 genotypes were analyzed in 178 Japanese COVID-19 patients to investigate the association of HLA with severe COVID-19. Analysis of 32 common HLA alleles at four loci revealed a significant association between HLA-DRB1*09:01 and severe COVID-19 (odds ratio [OR], 3.62; 95% CI, 1.57-8.35; p = 0.00251 [permutation p value = 0.0418]) when age, sex, and other common HLA alleles at the DRB1 locus were adjusted. The DRB1*09:01 allele was more significantly associated with risk for severe COVID-19 compared to preexisting medical conditions such as hypertension, diabetes, and cardiovascular diseases. These results indicate a potential role for HLA in predisposition to severe COVID-19.


Assuntos
COVID-19 , Cadeias HLA-DRB1 , Alelos , COVID-19/diagnóstico , COVID-19/genética , Frequência do Gene , Predisposição Genética para Doença , Genótipo , Cadeias HLA-DRB1/genética , Humanos
11.
Sci Rep ; 11(1): 5376, 2021 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-33686154

RESUMO

Although the spread of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) has resulted in a worldwide pandemic, there are currently no virus-specific drugs that are fully effective against SARS-CoV-2. Only a limited number of human-derived cells are capable of supporting SARS-CoV-2 replication and the infectivity of SARS-CoV-2 in these cells remains poor. In contrast, monkey-derived Vero cells are highly susceptibility to infection with SARS-CoV-2, although they are not suitable for the study of antiviral effects by small molecules due to their limited capacity to metabolize drugs compared to human-derived cells. In this study, our goal was to generate a virus-susceptible human cell line that would be useful for the identification and testing of candidate drugs. Towards this end, we stably transfected human lung-derived MRC5 cells with a lentiviral vector encoding angiotensin-converting enzyme 2 (ACE2), the cellular receptor for SARS-CoV-2. Our results revealed that SARS-CoV-2 replicates efficiently in MRC5/ACE2 cells. Furthermore, viral RNA replication and progeny virus production were significantly reduced in response to administration of the replication inhibitor, remdesivir, in MRC5/ACE2 cells compared with Vero cells. We conclude that the MRC5/ACE2 cells will be important in developing specific anti-viral therapeutics and will assist in vaccine development to combat SARS-CoV-2 infections.


Assuntos
Enzima de Conversão de Angiotensina 2/metabolismo , Antivirais/farmacologia , Engenharia Celular , Descoberta de Drogas , Modelos Biológicos , SARS-CoV-2/fisiologia , Animais , Antivirais/uso terapêutico , COVID-19/tratamento farmacológico , Linhagem Celular , Humanos , SARS-CoV-2/efeitos dos fármacos , Proteínas Virais/biossíntese , Replicação Viral/efeitos dos fármacos
12.
Int Immunol ; 33(4): 241-247, 2021 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-33538817

RESUMO

An expanded myeloid cell compartment is a hallmark of severe coronavirus disease 2019 (COVID-19). However, data regarding myeloid cell expansion have been collected in Europe, where the mortality rate by COVID-19 is greater than those in other regions including Japan. Thus, characteristics of COVID-19-induced myeloid cell subsets remain largely unknown in the regions with low mortality rates. Here, we analyzed cellular dynamics of myeloid-derived suppressor cell (MDSC) subsets and examined whether any of them correlate with disease severity and prognosis, using blood samples from Japanese COVID-19 patients. We observed that polymorphonuclear (PMN)-MDSCs, but not other MDSC subsets, transiently expanded in severe cases but not in mild or moderate cases. Contrary to previous studies in Europe, this subset selectively expanded in survivors of severe cases and subsided before discharge, but such transient expansion was not observed in non-survivors in Japanese cohort. Analysis of plasma cytokine/chemokine levels revealed positive correlation of PMN-MDSC frequencies with IL-8 levels, indicating the involvement of IL-8 on recruitment of PMN-MDSCs to peripheral blood following the onset of severe COVID-19. Our data indicate that transient expansion of the PMN-MDSC subset results in improved clinical outcome. Thus, this myeloid cell subset may be a predictor of prognosis in cases of severe COVID-19 in Japan.


Assuntos
COVID-19/patologia , Interleucina-8/sangue , Células Supressoras Mieloides/imunologia , Neutrófilos/imunologia , SARS-CoV-2/imunologia , Humanos , Interleucina-8/imunologia , Japão , Contagem de Leucócitos , Células Mieloides/imunologia , Ativação de Neutrófilo/imunologia
13.
Sci Immunol ; 6(55)2021 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-33419791

RESUMO

Much remains unknown about the roles of CD4+ T helper cells in shaping localized memory B cell and CD8+ T cell immunity in the mucosal tissues. Here, we report that lung T helper cells provide local assistance for the optimal development of tissue-resident memory B and CD8+ T cells after the resolution of primary influenza virus infection. We have identified a population of T cells in the lung that exhibit characteristics of both follicular T helper and TRM cells, and we have termed these cells as resident helper T (TRH) cells. Optimal TRH cell formation was dependent on transcription factors involved in T follicular helper and resident memory T cell development including BCL6 and Bhlhe40. We show that TRH cells deliver local help to CD8+ T cells through IL-21-dependent mechanisms. Our data have uncovered the presence of a tissue-resident helper T cell population in the lung that plays a critical role in promoting the development of protective B cell and CD8+ T cell responses.

14.
PLoS One ; 16(1): e0245244, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33412571

RESUMO

IgA antibodies, which are secreted onto the mucosal surface as secretory IgA antibodies (SIgAs), play an important role in preventing influenza virus infection. A recent study reported that anti-hemagglutinin (HA) head-targeting antibodies increase anti-viral functions such as hemagglutination inhibition (HI) and virus neutralization (NT), in addition to HA binding activity (reactivity) via IgA polymerization. However, the functional properties of anti-viral IgA antibodies with mechanisms of action distinct from those of anti-HA head-targeting antibodies remain elusive. Here, we characterized the functional properties of IgG, monomeric IgA, and polymeric IgA anti-HA stalk-binding clones F11 and FI6, and B12 (a low affinity anti-HA stalk clone), as well as Fab-deficient (ΔFab) IgA antibodies. We found that IgA polymerization impacts the functional properties of anti-HA stalk antibodies. Unlike anti-HA head antibodies, the anti-viral functions of anti-HA stalk antibodies were not simply enhanced by IgA polymerization. The data suggest that two modes of binding (Fab paratope-mediated binding to the HA stalk, and IgA Fc glycan-mediated binding to the HA receptor binding site (RBS)) occur during interaction between anti-stalk HA IgA antibodies and HA. In situations where Fab paratope-mediated binding to the HA stalk exceeded IgA Fc glycan-mediated binding to HA RBS, IgA polymerization increased anti-viral functions. By contrast, when IgA Fc glycan-mediated binding to the HA RBS was dominant, anti-viral activity will fall upon IgA polymerization. In summary, the results suggest that coordination between these two independent binding modules determines whether IgA polymerization has a negative or positive effect on the anti-viral functions of anti-HA stalk IgA antibodies.


Assuntos
Hemaglutininas/imunologia , Imunoglobulina A/imunologia , Vacinas contra Influenza/imunologia , Influenza Humana/prevenção & controle , Animais , Anticorpos Antivirais/química , Anticorpos Antivirais/imunologia , Afinidade de Anticorpos , Sítios de Ligação de Anticorpos , Células Cultivadas , Cães , Feminino , Células HEK293 , Hemaglutininas/química , Humanos , Imunogenicidade da Vacina , Imunoglobulina A/química , Virus da Influenza A Subtipo H5N1/imunologia , Células Madin Darby de Rim Canino , Camundongos , Camundongos Endogâmicos BALB C
15.
Virology ; 555: 35-43, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33450669

RESUMO

The pandemic of COVID-19 is still ongoing, and many studies on serum antibodies have been reported, however, there are few studies about asymptomatic and mild patients. In this study, we enrolled 44 COVID-19 patients with relatively mild disease and 48 pre-pandemic controls. We measured serum antibodies against extracellular domain, S1 domain, and receptor-binding domain of Spike and N protein, examined neutralization titers by authentic virus neutralization assay and newly-developed bead/cell-based Spike-ACE2 inhibition assay, and compared them with clinical features. Most of these antibodies, including neutralizing titers, were mutually correlated, and the production of antibodies were associated with low Ct values of PCR test, disease severity, symptoms especially pneumonia, lymphopenia, and serological test including CRP, LD, D-dimer, and procalcitonin. Notably, 87.5% of asymptomatic and 23.5% of mild patients did not have antibody against SARS-CoV-2. Our results revealed the inadequate acquisition of humoral immunity in patients with asymptomatic and mild COVID-19 patients.


Assuntos
Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , COVID-19/imunologia , Proteínas do Nucleocapsídeo de Coronavírus/imunologia , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Adulto , Enzima de Conversão de Angiotensina 2/metabolismo , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Infecções Assintomáticas , COVID-19/diagnóstico , COVID-19/fisiopatologia , Teste de Ácido Nucleico para COVID-19 , Proteínas do Nucleocapsídeo de Coronavírus/química , Feminino , Humanos , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Japão , Masculino , Pessoa de Meia-Idade , Fosfoproteínas/química , Fosfoproteínas/imunologia , Domínios Proteicos , Índice de Gravidade de Doença , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/metabolismo
16.
Bone ; 142: 115651, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32950699

RESUMO

Abaloparatide (ABL) is a novel 34-amino acid peptide analog of parathyroid hormone-related protein. In clinical studies, although ABL showed a greater bone mineral density (BMD) increase than teriparatide (TPTD, human parathyroid hormone 1-34), the responses of ABL to bone formation and resorption markers were weaker, making it difficult to understand the relationship between the bone anabolic window (increase in bone formation versus resorption) and bone mass. In the present study, the effects of ABL and TPTD were compared in mice. Given that the rate of bone turnover is higher in rodents than in humans, the comparison was made with several administration regimens providing equivalent daily dosages: once daily (QD, 30 µg/kg every 24 h), twice daily (BID, 15 µg/kg every 12 h), or three times a day (TID, 10 µg/kg every 8 h). Frequent administration of ABL showed higher BMD with enhancement of trabecular and cortical bone mass and structures than that of TPTD, consistent with the clinical results seen with once daily administration. ABL increased bone formation marker levels more than TPTD with more frequent regimens, while bone resorption marker levels were not different between ABL and TPTD in all regimens. Analysis of bone histomorphometry and gene expression also suggested that ABL increased bone formation more than TPTD, while the effect on bone resorption was almost comparable between ABL and TPTD. The bone anabolic windows calculated from bone turnover markers indicated that ABL enhanced the anabolic windows more than TPTD, leading to a robust increase in BMD. The mechanism by which ABL showed a better balance of bone turnover was suggested to be partly due to the enhanced remodeling-based bone formation involved in Ephb4. Taken together, our findings would help elucidate the mechanism by which ABL shows excellent BMD gain and reduction of fractures in patients with osteoporosis.


Assuntos
Conservadores da Densidade Óssea , Teriparatida , Animais , Densidade Óssea , Conservadores da Densidade Óssea/farmacologia , Humanos , Camundongos , Proteína Relacionada ao Hormônio Paratireóideo , Teriparatida/farmacologia
17.
Glycobiology ; 31(5): 557-570, 2021 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-33242079

RESUMO

Sialic acids are unique sugars with negative charge and exert various biological functions such as regulation of immune systems, maintenance of nerve tissues and expression of malignant properties of cancers. Alpha 2,6 sialylated N-glycans, one of representative sialylation forms, are synthesized by St6gal1 or St6gal2 gene products in humans and mice. Previously, it has been reported that St6gal1 gene is ubiquitously expressed in almost all tissues. On the other hand, St6gal2 gene is expressed mainly in the embryonic and perinatal stages of brain tissues. However, roles of St6gal2 gene have not been clarified. Expression profiles of N-glycans with terminal α2,6 sialic acid generated by St6gal gene products in the brain have never been directly studied. Using conventional lectin blotting and novel sialic acid linkage-specific alkylamidationmass spectrometry method (SALSA-MS), we investigated the function and expression of St6gal genes and profiles of their products in the adult mouse brain by establishing KO mice lacking St6gal1 gene, St6gal2 gene, or both of them (double knockout). Consequently, α2,6-sialylated N-glycans were scarcely detected in adult mouse brain tissues, and a majority of α2,6-sialylated glycans found in the mouse brain were O-linked glycans. The majority of these α2,6-sialylated O-glycans were shown to be disialyl-T antigen and sialyl-(6)T antigen by mass spectrometry analysis. Moreover, it was revealed that a few α2,6-sialylated N-glycans were produced by the action of St6gal1 gene, despite both St6gal1 and St6gal2 genes being expressed in the adult mouse brain. In the future, where and how sialylated O-linked glycoproteins function in the brain tissue remains to be clarified.

18.
Microbes Infect ; 23(1): 104767, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33049386

RESUMO

Several mechanisms underline induction of CD4 T-cell death by human immunodeficiency virus (HIV) infection. For a long time, apoptosis was considered central to cell death involved in the depletion of CD4 T cells during HIV infection. However, which types of cell death are induced during the early phase of HIV infection in vivo remains unclear. In this study, CD4 T-cell death induced in early HIV infection was characterized using humanized mice challenged with CCR5-tropic (R5) or CXCR4-tropic (X4) HIV-1. Results showed that CD4 T-cell death was induced in the spleen 3 days post-challenge with both R5 and X4 HIV-1. Although cell death without caspase-1 and caspase-3/7 activation was preferentially observed, caspase-1+ pyroptosis was also significantly induced within the memory subpopulation by R5 or X4 HIV-1 and the naïve subpopulation by X4 HIV-1. In contrast, caspase-3/7+ apoptosis was not enhanced by either R5 or X4 HIV-1. Furthermore, phosphorylated mixed lineage kinase domain-like protein+ necroptosis was induced by only X4 HIV-1. These findings indicate that various types of non-apoptotic CD4 T-cell death, such as pyroptosis and necroptosis, are induced during the early phase of HIV infection in vivo.

19.
J Virol ; 2020 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-33298539

RESUMO

Hepatitis B virus (HBV) infection is a major public health problem. Human hepatocytes are infected with HBV via binding between the preS1 region in the large envelope protein of HBV and sodium taurocholate cotransporting polypeptide. Although several monoclonal antibodies (MAbs) that recognize the receptor binding domain in preS1 and neutralize HBV infection have been isolated, details of neutralizing epitopes are not understood. In this study, we generated 13 MAbs targeting the preS1 receptor binding domain from preS1-specific memory B cells derived from DNA immunized mice. The MAbs were classified into three groups according to the epitope regions, designated epitopes I-III. A virus neutralization assay revealed that MAbs recognizing epitopes I and III neutralized HBV infection, suggesting that these domains are critical epitopes for viral neutralization. In addition, a neutralization assay against multiple genotypes of HBV revealed that epitope I is a semi-pangenotypic neutralizing epitope, whereas epitope III is a genotype-specific epitope. We also showed that neutralizing MAbs against preS1 could neutralize HBV bearing vaccine-induced escape mutation. These findings provide insight into novel immunoprophylaxis for the prevention and treatment of HBV infection.IMPORTANCE The HBV preS1 2-47 aa region (preS1/2-47) is essential for virus binding with sodium taurocholate cotransporting polypeptide. Several MAbs targeting preS1/2-47 have been reported to neutralize HBV infection; however, which region in preS1/2-47 contains the critical neutralizing epitope for HBV infection is unclear. Here, we generated several MAbs targeting preS1/2-47 and found that MAbs recognizing the N- or C-terminus of preS1/2-47 remarkably neutralized HBV infection. We further confirmed the neutralizing activity of anti-preS1 MAbs against HBV with vaccine escape mutation. These data clarified the relationship between the antibody epitope and the virus neutralizing activity and also suggested the potential ability of a vaccine antigen containing the preS1 region to overcome the weakness of current HB vaccines comprising the small S protein.

20.
Toxicol Res ; 36(4): 407-413, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33005597

RESUMO

In 2017, the second national reference standard (NRS) for Gloydius snake venom was established to replace the first NRS for Gloydius snake venom. In connection with the second venom NRS, a candidate for the first NRS for Gloydius snake antivenom was produced in 2017. In this study, the qualification of the candidate was estimated and the potency was determined by a collaborative study. The potency (anti-lethal titer and anti-hemorrhagic titer) of the candidate was determined by measuring the capability of the antivenom to neutralize the lethal and hemorrhagic effects of the second NRS for Gloydius snake venom, which was calibrated against the regional reference standard for Gloydius snake antivenom established in 2006. Two Korean facilities contributed data from 20 independent assays. Subsequently, one foreign national control research laboratories participated in this collaborative study. The general common potency of the anti-lethal and anti-hemorrhagic titers was obtained from the results of a total of 25 tests performed at three facilities. According to the results of the present study, the candidate preparation showed good quality and is judged to be suitable to serve as the first NRS for Gloydius snake antivenom with the following potency: an anti-lethal titer of 3100 unit (U) (95% confidence interval 2991-3276 U) and anti-hemorrhagic titer of 3000 U (95% confidence interval 2849-3159 U). In conclusion, the first NRS for Gloydius snake antivenom was established in this study. This reference standard will be used routinely for quality control of a snake antivenom product by manufacturer in Korea, which also can be used for national quality control, including a national lot-release test of the snake antivenom product.

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