Antibody isotype epitope mapping of SARS-CoV-2 Spike RBD protein: Targets for COVID-19 symptomatology and disease control

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) still poses a challenge for biomedicine and public health. To advance the development of effective diagnostic, prognostic, and preventive interventions, our study focused on high-throughput antibody binding epitope mapping of the SARS-CoV-2 spike RBD protein by IgA, IgM and IgG antibodies in saliva and sera of different cohorts from healthy uninfected individuals to SARS-CoV-2-infected unvaccinated and vaccinated asymptomatic, recovered, nonsevere, and severe patients. Identified candidate diagnostic (455-LFRKSNLKPFERD-467), prognostic (395-VYADSFVIRGDEV-407-C-KLH, 332-ITNLCPFGEV-342-C-KLH, 352-AWNRKRI-358-C-KLH, 524-VCGPKKSTNLVKN-536-KLH), and protective (MKLLE-487-NCYFPLQSYGFQPTNGVG-504-GGGGS-446-GGNYNYLYRLFRKSNLKPFERD-467) epitopes were validated with sera from prevaccine and postvaccine cohorts. The results identified neutralizing epitopes and support that antibody recognition of linear B-cell epitopes in RBD protein is associated with antibody isotype and disease symptomatology. The findings in asymptomatic individuals suggest a role for anti-RBD antibodies in the protective response against SARS-CoV-2. The possibility of translating results into diagnostic interventions for the early diagnosis of asymptomatic individuals and prognosis of disease severity provides new tools for COVID-19 surveillance and evaluation of risks in hospitalized patients. These results, together with other approaches, may contribute to the development of new vaccines for the control of COVID-19 and other coronavirus-related diseases using a quantum vaccinomics approach through the combination of protective epitopes.     

Differences in genetic stability between human cell lines from patients with and without lymphoreticular malignancy

Isozymes determined by 11 loci have been examined in 137 human lymphoblastoid lines of various origins with a view to determining their phenotypic stability in culture. Lines of normal origin are stable and at these loci are phenotypically identical to the individuals from whom they are derived. Lymphomas and some lines from patients with leukaemias show a tendency to increased apparent homozygosity, presumably resulting from loss of expression of one or other allele during culture. Taken together with the cytogenetic evidence this suggests that progressive loss of functional parts of the genome with time in culture is a characteristic of lines derived from malignant lymphoid cells.     

脊髓小脑共济性失调2型家系永生细胞株的建立及遗传稳定性检测

目的 建立伴帕金森氏病症状的脊髓小脑共济性失调2型家系永生细胞株,提供永久性的实验研究材料.方法 采用EB病毒加入环胞霉素A的转化细胞技术,建立了该家系的永生细胞株.并检测传代细胞与家系血液中的微卫星标记有无改变,确定细胞株的遗传稳定性.结果 成功建立此家系25株永生细胞株,所检测的微卫星位点未发生变化.结论 所建永生细胞株染色体核型检测无异常,转化细胞株与血液中的微卫星的遗传稳定性无差异.     

Host cell reactivation of sunlamp-exposed adenovirus in fibroblasts from patients with Bloom's syndrome, ataxia telangiectasia, and Huntington's disease

In this study, a sensitive host cell reactivation (HCR) technique was used to examine the repair capacity for DNA damaged by sunlamp exposure in fibroblast strains derived from 5 normal individuals and 8 patients representing three different diseases associated with DNA repair deficiencies. Adenovirus type 2 (Ad 2) was exposed to radiation from a GE 275 W sunlamp and subsequently used to infect fibroblast monolayers. At 48 hr after infection, cells were scored for the presence of viral structural antigens (Vag) using indirect immunofluorescent staining. Previous reports using this technique showed a substantial reduction in the HCR of sunlamp-exposed Ad 2 for infection of excision repair deficient fibroblasts from patients with xeroderma pigmentosum. In contrast, the HCR of Vag synthesis for sunlamp-exposed Ad 2 was in the normal range for the three ataxia telangiectasia, three Bloom's syndrome, and two Huntington's disease fibroblasts strains.     

Functional and cellular localization diversity associated with Fukutin‐related protein patient genetic variants

Genetic variants in Fukutin‐related protein (FKRP), an essential enzyme of the glycosylation pathway of α‐dystroglycan, can lead to pathologies with different severities affecting the eye, brain, and muscle tissues. Here, we generate an in vitro cellular system to characterize the cellular localization as well as the functional potential of the most common FKRP patient missense mutations. We observe a differential retention in the endoplasmic reticulum (ER), the indication of misfolded proteins. We find data supporting that mutant protein able to overcome this ER‐retention through overexpression present functional levels comparable to the wild‐type. We also identify a specific region in FKRP protein localized between residues 300 and 321 in which genetic variants found in patients lead to correctly localized proteins but which are nevertheless functionally impaired or catalytically dead in our model, indicating that this particular region might be important for the enzymatic activity of FKRP within the Golgi. Our system thus allows the functional testing of patient‐specific mutant proteins and the identification of candidate mutants to be further explored with the aim of finding pharmacological treatments targeting the protein quality control system.     

骨形态发生蛋白-7基因变异与新疆维吾尔族人糖尿病和胰岛素抵抗的相关性

目的 探讨骨形态发生蛋白-7(bone morphogenetic protein 7,BMP7)基因变异与新疆维吾尔族人糖尿病、胰岛素抵抗的关系.方法 采用以流行病学调查为基础的病例-对照研究,选取717名(男276人、女441人)维吾尔族人作为研究对象,根据是否患有糖尿病分成糖尿病组(502例,男191例、女311例)和正常对照组(215人,男85人、女130人).首先在48例维吾尔族糖尿病患者中测序筛查 BMP7基因功能区的变异位点,选取代表性变异位点应用TaqMan-PCR技术在研究人群中进行基因型鉴定并开展病例-对照关联研究.结果 在 BMP7基因的功能区共发现5个新的和8个已知的变异位点.BMP7基因的2个代表性变异位点rs6025422、rs17480735均符合Hardy-Weinberg平衡.男性人群中rs6025422变异的AA、AG、GG基因型在糖尿病组及正常对照组中的频率分布差异有统计学意义(P<0.05),但对P值校正后差异无统计学意义(P>0.05),而总人群及女性人群中rs6025422变异基因型频率分布在病例、对照组间差异无统计学意义(P>0.05).男性人群中rs6025422变异不同基因型组间空腹血糖、空腹胰岛素水平、HOMA指数存在差异,并且AA、AG、GG 3组呈现递减趋势(P<0.05),而在总人群及女性人群中未发现上述现象.Logistic分析提示男性人群中rs6025422变异GG基因型是糖尿病的保护性因素(OR=0.637,95%可信区间0.439～0.923,P<0.05).结论 BMP7基因变异位点rs6025422可能与新疆维吾尔族男性糖尿病、胰岛素抵抗相关.

Abstract：

Objective To investigate the association between the genetic variations of the functional region in bone morphogenetic protein gene (BMP7) with type 2 diabetes mellitus in Chinese Uygur individuals. Methods A case-control study was conducted based on epidemiological investigation. A total of 717 Uygur subjects (276 males and 441 females) were selected and divided into two groups: diabetes mellitus group (n=502, 191 males and 311 females) and control group (n=215, 85 males and 130 females). All exons, flanking introns and the promoter regions of BMP7 gene were sequenced in 48 Uygur diabetics. Representative variations were selected according to the minor allele frequency (MAF) and linkage disequilibrium and genotyped using the TaqMan polymerase chain reaction method in 717 Uygur individuals, a relatively isolated general population in a relatively homogeneous environment and a case-control study was conducted to test the association between the genetic variations of BMP7 gene and type 2 diabetes mellitus. Results Five novel and 8 known variations in the BMP7 gene were identified. All genotype distributions were tested for deviations from Hardy-Weinberg equilibrium (P>0.05). There was significant difference of genotype distribution of rs6025422 between type 2 diabetes mellitus and control groups in the male population (P<0.05, P adjusted >0.05), but there was no difference in total and female population (P>0.05). And the means of fasting blood glucose (FBG), fasting insulin and HOMA-index significantly decreased in individuals with AA, AG and GG genotypes of rs6025422 in male population (P<0.05), but not in total and female population (P>0.05). The logistic regression analysis showed that GG genotype of rs6025422 variation might be a protective factor for diabetes in male (OR=0.637,95% confidence interval 0.439-0.923,P<0.05). Conclusion The present study suggests that the rs6025422 polymorphism in BMP7 gene may be associated with diabetes mellitus and insulin resistance in Uygur men.     

Activity of glucocerebrosidase in extracts of different cell types from type 1 Gaucher disease patients

Glucocerebrosidase activity in extracts of leukocytes, Epstein-Barr virus transformed lymphocytes and fibroblasts from Portuguese Type 1 Gaucher disease patients was studied. The residual glucocerebrosidase activity in all extracts from patients was less than 25% if measured in the presence of bile salt taurocholate. However, if measured in the absence of bile salt the residual enzyme activity in extracts from patients was cell type specific: it was severely reduced in the case of fibroblasts, mildly reduced in the case of lymphoblasts and not significantly reduced in the case of leukocytes. The glucocerebrosidase activity in extracts from all control cell types was stimulated by taurocholate. In the patients the enzyme activity in fibroblasts extracts was also stimulated but that in lymphoblasts and leukocytes was inhibited by the bile salt. The differences in glucocerebrosidase activity (in the absence of taurocholate) in extracts from different cell types from Gaucher disease patients are attributable to differences in the proportion of glucocerebrosidase present as a monomer with low activity (form I) and as a highly active aggregate (form II) that may also contain sphingolipid activator protein 2 (SAP-2). In extracts from leukocytes and lymphocytes from Type 1 Gaucher disease patients, but not in those from fibroblasts, a relatively high proportion of enzyme is present in aggregated form with near normal specific activity.     

Mnk2蛋白水平与食管鳞癌预后的相关性

目的:检测丝裂原活化蛋白激酶相互作用激酶2(mitogen-activated protein kinase-interacting kinase-2,Mnk2)在食管鳞状细胞癌中的表达水平,并探讨其与患者生存预后的相关性。方法:收集临床食管鳞癌标本86例及癌旁正常食管组织54例,应用Western blot法和免疫组化SP法检测肿瘤组织及正常食管黏膜组织中Mnk2蛋白表达水平,并用Kaplan-Meier生存曲线和Cox比例风险回归模型的方法探究其与食管鳞癌患者预后的关系。结果:Mnk2在食管癌组织中呈高表达,并且Mnk2蛋白表达与食管鳞癌的TNM分期密切相关(P0.05),同时Mnk2蛋白高表达组的无疾病进展生存期和总生存期均少于Mnk2低表达组,多因素分析提示Mnk2是食管鳞癌的独立预后因子。结论:Mnk2在食管鳞癌组织中的表达与TNM分期有关,同时可作为预测食管鳞癌患者预后的指标。     

NKG2D ligands expression patterns in gut mucosa from patients with coeliac disease

Introduction

The activating MICA/NKG2D interaction is involved in the response of intraepithelial lymphocytes (IELs) in coeliac disease (CD). The aim of this study was to investigate the expression of NKG2D ligands (MICA, MICB), IL-15 and NKG2D receptor in gut mucosa of CD patients, and the correlation with the severity of histological damage.

Patients and methods

Intestinal biopsies from 20 CD patients and five healthy controls were selected. All patients were positive for anti-transglutaminase 2 antibodies and for DQ2 or DQ8. Patients were divided into two groups according to their grade of mucosal impairment: ten each with mild and severe mucosal damage (MMD and SMD, respectively). The expression of proposed genes was determined at mRNA level. MICA expression was also determined by immunohistochemistry.

Results

Overexpression of MICA and MICB was observed in biopsies from coeliac patients compared to healthy controls (P < 0.001). Nevertheless, the expression was considerably higher in the group of patients with MMD (P < 0.0001) than in those with SMD. The levels of NKG2D receptor and IL-15 were also higher in patients than in controls, but no relationship with the severity of the mucosal lesion was found.

Conclusions

Our results suggest that NKG2D ligands may play an important role during the onset of the inflammatory process in the early stages of the development of coeliac disease.     

B and T cell immunity in patients with lysinuric protein intolerance.

Lysinuric protein intolerance (LPI) is characterized by defective cellular transport of the dibasic amino acids, secondary dysfunction of the urea cycle, aversion to dietary protein, failure to thrive, hepatosplenomegaly and osteoporosis. Because several patients have suffered from recurrent respiratory infections and/or severe generalized varicella, and a few have developed systemic lupus, vasculitis or other autoimmune diseases, we have now evaluated the function of patients' immune systems. Serum concentrations of one to three IgG subclasses were decreased in 10 of the 12 patients studied. Antibody titres against diphtheria, tetanus and Haemophilus influenzae (Hib) were below the detection limit of the assay in four, three and eight of the 11 patients examined, respectively. (Re)vaccination of these 11 patients led to satisfactory responses against tetanus, but two patients still failed to develop measurable antibodies against diphtheria, two against Hib and six against one or more of the three serotypes of 23-valent pneumococcus vaccine. The proportions of T cells of all lymphocytes and the proliferative responses of the peripheral blood mononuclear cells were normal. In conclusion, humoral immune responses in some patients with LPI are defective and these patients may benefit from intravenous immunoglobulin therapy.     

婆罗双树样基因4在人前列腺癌细胞和组织中的表达及其与临床预后之间的关系

 目的：评估婆罗双树样基因4（SALL4）在人前列腺癌细胞系和前列腺癌组织中的表达情况,并明确其表达水平和临床病理学参数间的关系。方法：用免疫荧光技术、RT-PCR和Western blotting检测SALL4在LNCaP、DU145、PC-3细胞系和RWPE-1正常前列腺上皮细胞系中的表达。同时用免疫组化方法检测SALL4在前列腺增生及前列腺癌组织中的表达,并探讨其与Gleason评分等临床病理参数的关系。结果： SALL4蛋白在细胞中主要表达于胞浆,在3种前列腺癌细胞株中SALL4蛋白表达水平要明显高于正常前列腺上皮细胞RWPE-1（P＜005）,而SALL4 mRNA表达水平在4种细胞系中无明显差异（P＞0.05）。免疫组化结果显示SALL4在前列腺癌组织中的表达水平明显高于增生和正常前列腺组织（P＜0.01）。SALL4蛋白表达水平与Gleason评分、前列腺癌临床分期、预后及组织前列腺特异抗原（PSA）表达密切相关,而与患者年龄、治疗前血清总PSA水平、前列腺体积及组织雄激素受体表达无明显相关性。结论：SALL4蛋白在前列腺癌中高表达,提示其在前列腺癌的发生、发展过程中可能起重要作用,有可能成为诊断前列腺癌新的肿瘤标志物及评估其恶性程度、进展和预后的参考指标。     

HLA class I and class II frequencies in patients with sarcoidosis from Croatia: role of HLA-B8, -DRB1*0301, and -DQB1*0201 haplotype in clinical variations of the disease

Sarcoidosis is an immune-mediated, multiorgan, granulomatous disease triggered by a combination of environmental and genetic factors. Numerous studies have reported about an association of human leukocyte antigen (HLA) alleles with sarcoidosis, with variation of alleles in different ethnic groups. Therefore, we investigated 142 Croatian sarcoidosis patients treated at the University Hospital for Lung Diseases Jordanovac, Zagreb, Croatia. Diagnosis was based on the presence of typical clinical features, chest X-ray findings and biopsy evidence of granuloma. Patients and control subjects (n = 190) were typed for HLA class I antigens by serology, while for HLA class II, they were tested by the polymerase chain reaction-sequence specific primers (PCR-SSP) method. Results indicated that HLA-B8, -DRB1*0301, and -DQB1*0201 positive patients have a significantly higher risk of acute onset of the disease (AOD), radiological stage I erythema nodosum (EN), L?fgren's syndrome, no-medicament therapy, and pulmonary sarcoidosis. On the other hand, the group of non-treated patients (corticosteroids and/or immunosuppressive) showed a significantly lower presence of HLA-B15 antigen in comparison to controls and treated patients (P = 0.0490 and P = 0.0379, respectively) and for DRB1*04 specificity (P = 0.0078 and P = 0.0065, respectively). In the group of patients with AOD, those who were positive for DRB1*16 specificity have a statistically significant chance to develop EN, as opposed to those who are positive for DRB1*15 specificity.     

The association of cholesteryl ester transfer protein polymorphism with high-density lipoprotein cholesterol and coronary artery disease in Koreans

Cholesteryl ester transfer protein (CETP) is a key protein involved in high-density lipoprotein cholesterol (HDL-C) metabolism. It is known to affect plasma HDL-C levels, and its genetic regulation may be involved in the development of coronary artery disease (CAD). The aim of this study was to determine the frequency of the CETP Taq1B polymorphism in Koreans, and to investigate its relationship with plasma HDL-C levels and CAD. One-hundred and nineteen patients with significant CAD and 106 controls were examined with respect to their genotypes, lipid profiles and other risk factors of CAD. The genotype frequencies of B1B1:B1B2:B2B2 in males and females were 35.5%:50%:14.5% and 34.7%:42.6%:22.7%, respectively, which is comparable to previous reports in other ethnic groups. The B1B1 homozygote was associated with significantly lower HDL-C levels in females (p = 0.049) and non-smoking males (p = 0.037). After controlling for gender, body mass index (BMI) and smoking, the TaqIB polymorphism was still significantly associated with HDL-C levels (p = 0.046) and explained 5.4% of the HDL-C variation in this study. By univariate analysis, the B1B1 homozygote was a significant predictor of CAD (p = 0.043), and this was confirmed by multivariate analysis with traditional risk factors, i.e. the B1B1 homozygote was an independent predictor of CAD (p = 0.026, odds ratio = 1.97, 95% confidence interval: 1.08-3.57). In conclusion, the B1B1 homozygote of the CETP Taq1B polymorphism is associated with low HDL-C levels in females and non-smoking males, and may be an independent genetic risk factor of CAD in the Korean population.     

Autoimmunity to a 28-30 kD cell membrane DNA binding protein: occurrence in selected sera from patients with SLE and mixed connective tissue disease (MCTD).

Previous experiments have established the presence of a 30-kD DNA binding protein on the surface of human leukocytes. Herein we report that selected sera from patients with systemic lupus erythematosus (SLE) and MCTD are reactive with a 28-30 kD protein on immunoblots of peripheral blood mononuclear cells (PBMC) cell membrane preparations; the reactivity is abolished by prior incubation of the blot with DNA. Antibodies eluted from the 28-30 kD strip inhibited the binding of 3H. DNA to human PBMC. An immunomatrix of 28-30 kD reactive immunoglobulins was able to extract a 29-kD DNA binding protein from a PBMC cell membrane preparation. Flow cytometry experiments confirmed the cell surface IgG reactivity of sera with T lymphocytes. Additional experiments indicated that cell surface IgG binding was not due to antibodies binding to cell surface DNA, DNA anti-DNA immune complexes reacting with a DNA binding protein, anti-histone antibodies or anti-Sm antibodies. It is hypothesized that this autoimmune response could be one component of an idiotypic network involving anti-DNA antibodies.     

High expression of immunity-related GTPase family M protein in glioma promotes cell proliferation and autophagy protein expression

Glioma is the commonest malignant tumor in the central nervous system (CNS), characterized by rapid growth. However, the molecular mechanism underlying the growth remains unclear. Immunity-related GTPase family M protein (IRGM) participates in immune response to pathogen and tumorigenesis. Proliferation and autophagy are two crucial functions contributing to aggressive growth. Therefore, our aims were to probe whether IRGM regulates glioma proliferation and autophagy. In this study, we found that 47 glioma specimens had more IRGM expression than 11 non-cancerous brain tissues with immunohistochemistry. IRGM was also up-regulated in human glioma cell lines U87, U251 and A172 and so on compared with immortalized astrocytes. Importantly, overexpression of IRGM significantly increased the cell colonies formation, cell proliferation and Akt activation (Thr308 and Ser473 sites) than matched control. On another hand, all of IRGM, autophagy marker LC3II and autophagy adaptor p62 gradually increased after starvation 2 and 4?h. Furthermore, western blot and immunofluorescence results showed that knockdown of IRGM inhibited the formation of LC3-II and the expression of p62. Our data uncovered that IRGM acted in glioma proliferation and autophagy, providing a new target with dual roles for the future translation research.