Common Antigen Research Articles

Balancing the influenza neuraminidase and hemagglutinin responses by exchanging the vaccine virus backbone.

Virions are a common antigen source for many viral vaccines. One limitation to using virions is that the antigen abundance is determined by the content of each protein in the virus. This caveat especially applies to viral-based influenza vaccines where the low abundance of the neuraminidase (NA) surface antigen remains a bottleneck for improving the NA antibody response. Our systematic analysis using recent H1N1 vaccine antigens demonstrates that the NA to hemagglutinin (HA) ratio in virions can be improved by exchanging the viral backbone internal genes, especially the segment encoding the polymerase PB1 subunit. The purified inactivated virions with higher NA content show a more spherical morphology, a shift in the balance between the HA receptor binding and NA receptor release functions, and induce a better NA inhibitory antibody response in mice. These results indicate that influenza viruses support a range of ratios for a given NA and HA pair which can be used to produce viral-based influenza vaccines with higher NA content that can elicit more balanced neutralizing antibody responses to NA and HA.

The Detailed Study of CD10: A Stromal Marker in Breast Carcinoma

Breast carcinoma is one of the most frequently occurring cancers among women with one million cases. Breast cancer is the primary cause of death in women around the world. It is one of the major concerns in public health due to its high occurrence and growing tendency. This complex functional structure develops from a highly modified apocrine sweat gland in the female, but remains rudimentary in male. Breast develops embryological into two lines along milk lines extending from axilla to groin. CD-10 is a 90- to 110-kDa cell surface zinc dependent metalloproteinase which is known as “Common Acute Lymphoblastic Leukaemia Antigen” (CALLA). CD-10 acts as a stem cell regulator in the breast and prevents uncontrolled proliferation on stem cells The present study is designed to study the expression of CD-10, a breast carcinoma stromal marker and its correlation with ER, PR and HER2/neu status in breast carcinoma.

Developing a databank for multiple transfusion patients: Rh antigen and phenotype distribution among 3000 regular blood donors in Iran

BackgroundRhesus (Rh) blood group system is clinically the most significant protein-based grouping system. The Rh system is of vital importance in blood transfusion, and incompatibility between the donor and recipient leads to alloimmunization. Alloimmunization is commonly seen in multiple-transfusion recipients (e.g. thalassemia patients). There are a few studies about the prevalence of Rh antigens, except for D, in Iran; and regarding the high prevalence of thalassemia in the country, in this study we have determined antigens and phenotypes of the Rh among population of regular blood donors with the aim of developing a detailed Rh databank. Materials and methodsThis cross-sectional study randomly enrolled 3000 regular blood donors from three provinces of Sistan-Balouchestan, Khuzestan and Gilan in Iran, from September 2018 to May 2019. A fully automated system, based on hemagglutination, was used to Rh typing of blood samples. ResultsThe prevalence of Rh antigens were as follows: D: 88.9 %; E: 30.9 %; C: 74.1 %; e: 96.2 %; and c: 72.8 %. The most common antigen and phenotype were "e" and R1r (DCcee), respectively. ConclusionDue to the high rate of alloimmunization incidence against Rh blood group antigens among multiple transfusion recipients, development of regular blood donor's Rh databank can facilitate extensive matching for the Rh antigens and it likely reduces the risk of alloimmunization.

Immunization against Pseudomonas aeruginosa using Alg-PLGA nano-vaccine.

Objective(s): Pseudomonas aeruginosa is the bacterium that causes of pulmonary infection among chronically hospitalized patients. Alginate is a common surface antigen of P. aeruginosa with a constant structure that which makes it an appropriate target for vaccines. In this study, P. aeruginosa alginate was conjugated with to PLGA nanoparticles, and its immunogenicity was characterized as a vaccine.Materials and Methods:Alginate was isolated from a mucoid strain of P. aeruginosa and conjugated with to PLGA with˝ N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride ˝= ˝EDAC˝ and N-Hydroxysuccinimide (NHS). Chemical characterization of prepared nano-vaccine was performed using FTIR Spectroscopy, Zetasizer, and Atomic Force Microscopy (AFM). The immunogenicity of this nano-vaccine was evaluated through intramuscular injection into BALB/c mice. Four groups of mice were subjected to the injection of alginate–PLGA, and two weeks after the last administration step, opsonophagocytosis assay, IgG detection, challenge, and cytokine determination via ELISA were carried out.Results:Alginate-PLGA conjugation was corroborated by FTIR, Zetasizer, and AFM. The ELISA consequence showed that alginate was prospering in the instigation of the humoral immunity.The immunogenicity enhanced against the alginate-PLGA. Remarkably diminished bacterial titer in the spleen of the immunized mice posterior to challenge with PAO1 strain in comparison with the alginate alone and control groups.Conclusion:The bacterial burden in the spleen significantly decreased after the challenge (P<0.05). The opsonic activity was significantly increased in the alginate- PLGA group (P<0.05).

Efficient delivery of oncolytic enterovirus by carrier cell line NK-92

Many members of the enterovirus family are considered as promising oncolytic agents; however, their systemic administration is largely inefficient due to the rapid neutralization of the virus in the circulation and the barrier functions of the endothelium. We aimed to evaluate natural killer cells as carriers for the delivery of oncolytic enteroviruses, which would combine the effects of cell immunotherapy with virotherapy. We tested four strains of nonpathogenic enteroviruses against the glioblastoma cell line panel and evaluated the produced infectious titers. Next, we explored whether these virus strains could be delivered to the tumor by natural killer cell line NK-92, which is being actively evaluated as a clinically acceptable therapeutic. Several strains of enteroviruses demonstrated oncolytic properties, but only coxsackievirus A7 (CVA7) could replicate in NK-92 cells efficiently. We compared the delivery efficiency of CVA7 in vivo, using NK-92 cells and direct intravenous administration, and found significant advantages of cell delivery even after a single injection. This suggests that the NK-92 cell line can be utilized as a vehicle for the delivery of the oncolytic strain of CVA7, which would improve the clinical potential of this viral oncolytic for the treatment of glioblastoma multiforme and other forms of cancer.

Construction and Application of an Escherichia coli Strain Lacking 62 Genes Responsible for the Biosynthesis of Enterobacterial Common Antigen and Flagella.

The biosynthesis of the enterobacterial common antigen and flagella in Escherichia coli consumes lots of substrates and energy. In this study, 12 genes responsible for the biosynthesis of the enterobacterial common antigen were deleted in E. coli MG1655, resulting in WQM021. WQM021 grew better than MG1655 in both rich LB medium and minimum M9 medium. Compared with MG1655, WQM021 showed higher membrane permeability and higher production efficiency for recombinant proteins, polyhydroxyalkanoate, and l-threonine. Transcriptome analysis revealed that genes relevant to glucose consumption, glycolysis, and flagellar synthesis were significantly upregulated in WQM021. Therefore, 50 genes responsible for flagellar biosynthesis were further deleted in WQM021, resulting in WQM022. WQM022 grew better and could synthesize more polyhydroxyalkanoate and l-threonine than WQM021. The results demonstrate that the productivity of E. coli can be efficiently improved when the enterobacterial common antigen and flagella are eliminated. This strategy has guiding significance in the optimization of other industrial products and microorganisms.

Diagnostic Pattern of Adult Acute Leukemia in Benghazi Medical Center/ Libya

Objective: To study the demographic characters and diagnostic tools of acute leukemia among adults in Benghazi/ Libya. Patients and Method: A retrospective cross sectional analysis of 54 cases of AML and ALL was conducted at hematology department at Benghazi medical center (BMC) from January 2013 to December 2014. Demographic data, Complete Blood Picture (CBC), Peripheral Blood Film (PBF), Bone Marrow Aspiration (BMA), immunophenotyping as well as cytogenetic if applicable were evaluated. Result: Forty-two (77.8%) were diagnosed as AML and twelve (22.2%) as ALL. The median age for diagnosis of AML was 43 years. with male to female ratio 1.3:1 while for ALL the median age was 20 years, and male to female ratio was 2:1. Anemia was noted in (90.5%) and (100%) for AML and ALL, respectively. Thrombocytopenia was detected in (83%) for both types. Almost half of AML patients (47%) and (41%) of ALL cases presented with leukocytosis. Blasts were detected in more than two third (74%) of PBF of AML and (75%) in ALL patients. CD13 and CD33 and cyMPO were the most common positive myeloid presenting antigens. However, in ALL B-lymphoid markers CD10 and CD19 were the major positive antigens. Conclusion: AML was most common than ALL in adults, AML was common in middle age while ALL in young age group. Hematology departments require urgent improvement of diagnostic services in Libya in order to ensure good clinical management.

Making the Enterobacterial Common Antigen Glycan and Measuring Its Substrate Sequestration.

The enterobacterial common antigen (ECA), a three-sugar repeat unit polysaccharide produced by Enterobacteriaceae family members, impacts bacterial outer membrane permeability, and its biosynthesis affects the glycan landscape of the organism. ECA synthesis impacts the production of other polysaccharides by reducing the availability of shared substrates, the most notable of which is the 55-carbon polyisoprenoid bactoprenyl phosphate (BP), which serves as a carrier for the production of numerous bacterial glycans including ECA, peptidoglycan, O-antigen, and more. Here, using a combination of in vitro enzymatic synthesis and liquid chromatography-mass spectrometry (LC-MS) analysis of bacterial lysates, we provide biochemical evidence for the effect on endogenous polyisoprenoid pools from cell culture that arises from glycan pathway disruption. In this work, we have cloned and expressed each gene involved in ECA repeat unit biosynthesis and reconstituted the pathway in vitro, providing LC-MS characterized standards for the investigation of cellular glycan-linked intermediates and BP. We then generated ECA deficient mutants in genes associated with production of the polysaccharide, which we suspected would accumulate materials identical to our standards. We found that indeed accumulated products from these cells were indistinguishable from our enzymatically prepared standards, and moreover we observed a concomitant decrease in cellular BP levels with each mutant. This work provides the first direct biochemical evidence for the sequestration of BP upon the genetic disruption of glycan biosynthesis pathways in bacteria. This work also provides methods for the direct assessment of both the ECA glycan, and a new understanding of the dynamic interdependence of the bacterial polysaccharide repertoire.

Protective Effect of Pyrus ussuriensis Maxim. Extract against Ethanol-Induced Gastritis in Rats.

Pyrus ussuriensis Maxim (Korean pear) has been used for hundreds of years as a traditional herbal medicine for asthma, cough, and atopic dermatitis in Korea and China. Although it was originally shown to possess anti-inflammatory, antioxidant, and antiatopic properties, its gastroprotective effects have not been investigated. In the present study, we evaluated the protective effects of Pyrus ussuriensis Maxim extract (PUE) against ethanol-induced gastritis in rats. The bioactive compound profile of PUE was determined by gas chromatography mass spectroscopy (GC-MS) and high-performance liquid chromatography (HPLC). The gastroprotection of PUE at different doses (250 and 500 mg/kg body weight) prior to ethanol ingestion was evaluated using an in vivo gastritis rat model. Several endpoints were evaluated, including gastric mucosal lesions, cellular degeneration, intracellular damage, and immunohistochemical localization of leucocyte common antigen. The gastric mucosal injury and ulcer score were determined by evaluating the inflamed gastric mucosa and by histological examination. To identify the mechanisms of gastroprotection by PUE, antisecretory action and plasma prostaglandin E2 (PGE2), gastric mucosal cyclic adenosine monophosphate (cAMP), and histamine levels were measured. PUE exhibited significant antioxidant effects with IC50 values of 56.18 and 22.49 µg/mL for 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′- azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) inhibition (%), respectively. In addition, GC/MS and HPLC analyses revealed several bioactive compounds of PUE. Pretreatment with PUE significantly (p < 0.05) decreased the ulcer index by preventing gastric mucosal lesions, erosion, and cellular degeneration. An immunohistochemical analysis revealed that PUE markedly attenuated leucocyte infiltration in a dose-dependent manner. The enhancement of PGE2 levels and attenuation of cAMP levels along with the inhibition of histamine release following PUE pretreatment was associated with the cytoprotective and healing effects of PUE. In contrast, the downregulation of the H+/K+ ATPase pathway as well as muscarinic receptor (M3R) and histamine receptor (H2R) inhibition was also involved in the gastroprotective effects of PUE; however, the expression of cholecystokinin-2 receptors (CCK2R) was unchanged. Finally, no signs of toxicity were observed following PUE treatment. Based on our results, we conclude that PUE represents an effective therapeutic option to reduce the risk of gastritis and warrants further study.

Bispecific antibodies targeting mutant RAS neoantigens.

Mutations in the RAS oncogenes occur in multiple cancers, and ways to target these mutations has been the subject of intense research for decades. Most of these efforts are focused on conventional small-molecule drugs rather than antibody-based therapies because the RAS proteins are intracellular. Peptides derived from recurrent RAS mutations, G12V and Q61H/L/R, are presented on cancer cells in the context of two common human leukocyte antigen (HLA) alleles, HLA-A3 and HLA-A1, respectively. Using phage display, we isolated single-chain variable fragments (scFvs) specific for each of these mutant peptide-HLA complexes. The scFvs did not recognize the peptides derived from the wild-type form of RAS proteins or other related peptides. We then sought to develop an immunotherapeutic agent that was capable of killing cells presenting very low levels of these RAS-derived peptide-HLA complexes. Among many variations of bispecific antibodies tested, one particular format, the single-chain diabody (scDb), exhibited superior reactivity to cells expressing low levels of neoantigens. We converted the scFvs to this scDb format and demonstrated that they were capable of inducing T cell activation and killing of target cancer cells expressing endogenous levels of the mutant RAS proteins and cognate HLA alleles. CRISPR-mediated alterations of the HLA and RAS genes provided strong genetic evidence for the specificity of the scDbs. Thus, this approach could be applied to other common oncogenic mutations that are difficult to target by conventional means, allowing for more specific anticancer therapeutics.

Persistent TCell Repertoire Perturbation and TCell Activation in HIV After Long Term Treatment.

ObjectiveIn people living with HIV (PLHIV), we sought to test the hypothesis that long term anti-retroviral therapy restores the normal T cell repertoire, and investigate the functional relationship of residual repertoire abnormalities to persistent immune system dysregulation.MethodsWe conducted a case-control study in PLHIV and HIV-negative volunteers, of circulating T cell receptor repertoires and whole blood transcriptomes by RNA sequencing, complemented by metadata from routinely collected health care records.ResultsT cell receptor sequencing revealed persistent abnormalities in the clonal T cell repertoire of PLHIV, characterized by reduced repertoire diversity and oligoclonal T cell expansion correlated with elevated CD8 T cell counts. We found no evidence that these expansions were driven by cytomegalovirus or another common antigen. Increased frequency of long CDR3 sequences and reduced frequency of public sequences among the expanded clones implicated abnormal thymic selection as a contributing factor. These abnormalities in the repertoire correlated with systems level evidence of persistent T cell activation in genome-wide blood transcriptomes.ConclusionsThe diversity of T cell receptor repertoires in PLHIV on long term anti-retroviral therapy remains significantly depleted, and skewed by idiosyncratic clones, partly attributable to altered thymic output and associated with T cell mediated chronic immune activation. Further investigation of thymic function and the antigenic drivers of T cell clonal selection in PLHIV are critical to efforts to fully re-establish normal immune function.

Genomic diversity and organization of complex polysaccharide biosynthesis clusters in the genus Dickeya.

The pectinolytic genus Dickeya (formerly Erwinia chrysanthemi) comprises numerous pathogenic species which cause diseases in various crops and ornamental plants across the globe. Their pathogenicity is governed by complex multi-factorial processes of adaptive virulence gene regulation. Extracellular polysaccharides and lipopolysaccharides present on bacterial envelope surface play a significant role in the virulence of phytopathogenic bacteria. However, very little is known about the genomic location, diversity, and organization of the polysaccharide and lipopolysaccharide biosynthetic gene clusters in Dickeya. In the present study, we report the diversity and structural organization of the group 4 capsule (G4C)/O-antigen capsule, putative O-antigen lipopolysaccharide, enterobacterial common antigen, and core lipopolysaccharide biosynthesis clusters from 54 Dickeya strains. The presence of these clusters suggests that Dickeya has both capsule and lipopolysaccharide carrying O-antigen to their external surface. These gene clusters are key regulatory components in the composition and structure of the outer surface of Dickeya. The O-antigen capsule/group 4 capsule (G4C) coding region shows a variation in gene content and organization. Based on nucleotide sequence homology in these Dickeya strains, two distinct groups, G4C group I and G4C group II, exist. However, comparatively less variation is observed in the putative O-antigen lipopolysaccharide cluster in Dickeya spp. except for in Dickeya zeae. Also, enterobacterial common antigen and core lipopolysaccharide biosynthesis clusters are present mostly as conserved genomic regions. The variation in the O-antigen capsule and putative O-antigen lipopolysaccharide coding region in relation to their phylogeny suggests a role of multiple horizontal gene transfer (HGT) events. These multiple HGT processes might have been manifested into the current heterogeneity of O-antigen capsules and O-antigen lipopolysaccharides in Dickeya strains during its evolution.

Characterization of Antigenic Property of Adult Spirocerca lupi Collected from Esophageal Nodules in Dogs

Spirocerca lupi, the esophageal nematode of dog , causes a potentially fatal disease in domestic dogs. Immunological techniques can identify the parasite proteins which elicit an immune response. However, the antigenic properties of S. lupi adult worms have not been fully understood. The immuno-reactivity of the naturally infected dog sera with the S. lupi somatic antigens showed 7 prominent immunoreactive bands of distinct sizes at 199, 148, 100, 87, 49, 16, and 12 kDa, whereas 8 prominent bands at 230, 200, 100, 60, 49, 29, 16, and 12 kDa against hyper immune serum raised in the rabbits. Common antigen bands for both types of serum were observed at 100, 49 , 16 and 12 kDa. Intriguingly, the current study was able to indicate the detailed antigenic profile with specific molecular moieties which might be a manifesto for future investigation. Identified specific antigens merit further analysis as potential tools for the evaluation of treatment success and prognosis of spirocercosis, and development of a sensitive and specific diagnostic test for early detection of S. lupi in infected dogs.

Evolutionary model of brain tumor circulating cells: Cellular galaxy.

BACKGROUNDAlthough circulating tumor cells (CTCs) have been the focus of consideration for a decade, a categorized cell-based diagnostic strategy is unavailable. The personalized management and complementary/analytical-strategy of data require an alphabetic guide. Therefore, we aimed to determine the behavior of CTCs in tumor and blood in order to provide the hypothetical-based agenda in the brain neoplasms. Exploring the protein expression (PE) using a single cell-based method would clarify the heterogeneity and diversity in tumor and blood, which are key events in the evolution in brain tumors. In fact, heterogeneity, diversity, and evolution are required for cancer initiation and progression. AIMTo explore CTCs in brain tumors and blood cells and to assay intensity of PE through personalized insight.METHODSThe focal population included 14 patients with meningioma, and four patients with metastatic brain tumors (T). PE was assayed by immunofluorescence in tumors cells and CTCs in 18 patients with brain tumors. Ratio test was applied between the T cells and CTCs in tumor tissue and in vascular system. T/CTC ratio-based classification of PE in macrophage chemoattractant chemokine ligand 2 (CCL2), vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), CD133, cyclin E, neurofilament marker, cytokeratin 19, and leukocyte common antigen (CD45) were investigated. RESULTSTotal analyzed cells ranged between 10794-92283 for tumor cells and between 117-2870 for CTCs. Characteristics of histopathologic and status of an ataxia-telangiectasia mutated polymorphism (D1853N) in 18 patients affected with brain tumors were also provided. The course of evolution and metastatic event relied on the elevated protein expression in CTCs, which could be considered as a prognostic value. Diverse protein expression of the migrated cells into the blood stream and the tumor was indicative of the occurrence of evolution. Besides, the harmonic co-expression between CCL2/EGF and CCL2/VEGF could facilitate the tumor progression including the metastatic event. Expression of these proteins in the migrated vasculature and into the buccal tissue offered a non-invasive follow-up detection in neoplastic disorders. PE-exploration of neurofilament marker/CD133/VEGF of the CTCs in meningioma and cytokeratin 19/CD45/ cyclin E in the patients with metastatic brain tumor would clarify the tumor biology of the brain neoplastic disorders. CONCLUSIONThe alphabetical base of the evolutionary mechanisms relies on dual-, triple-, and multi-models with diverse intensity of expression. In fact, cross-talk between initiative and the complementary channels defines the evolutionary insight in cancer. A diverse-model of protein expression, including low, medium, and high intensity, is the key requirement for the completed model. The cluster of cells with diverse expression and remarkable co-expression between CCL2/EGF/VEGF and NM/CD133/VEGF in CTCs may be indicative of probable invasiveness of the tumor. Furthermore, the mode of cytokeratin-19+/CD45- can be traced in the metastatic patients.

Genomic analysis of VIM-2-producing Enterobacter hormaechei subsp. steigerwaltii

Carbapenemase-producing Enterobacterales (CPE) is a major public-health concern. Here we describe the occurrence of blaVIM-2 in three isolates of Enterobacter hormaechei subsp. steigerwaltii. The blaVIM-2 gene was part of a class II transposon Tn1332 and was embedded in a remnant of a class 1 integron. Tn1332 was carried by a large, conjugative, non-typeable plasmid. The three isolates belonged to sequence type 90 (ST90). Two isolates (90H2 and 90H3) were highly related [<10 single nucleotide polymorphisms (SNPs)], whereas isolate 104D2 exhibited more than 50 SNPs and Tn1332 was inserted in a different place in the plasmid. Another IncHI-type plasmid carrying the extended-spectrum β-lactamase (ESBL) gene blaCTX-M-15 was identified in 90H2 and 90H3. Among the three isolates, isolate 104D2 was negative for detection of carbapenemase activity using the biochemical Carba NP test, despite the presence of Tn1332 on the same plasmid. Mutants of 104D2 with higher minimum inhibitory concentrations (MICs) for carbapenems were obtained and one mutant (m104D2) was analysed. In contrast to 104D2, mutant m104D2 gave a positive Carba NP test. The mutant possessed two copies of Tn1332 per cell and a nonsense mutation in WecA, an enzyme involved in enterobacterial common antigen and peptidoglycan intermediate biosynthesis. This study describes the first occurrence of Tn1332 in Enterobacterales and the phenotypic diversity of VIM-2-producing E. hormaechei.

A New Look at the Enterobacterial Common Antigen Forms Obtained during Rough Lipopolysaccharides Purification.

Enterobacterial common antigen (ECA) is a conserved antigen expressed by enterobacteria. It is built by trisaccharide repeating units: →3)-α-D-Fucp4NAc-(1→4)-β-D-ManpNAcA-(1→4)-α-D-GlcpNAc-(1→ and occurs in three forms: as surface-bound linear polysaccharides linked to a phosphoglyceride (ECAPG) or lipopolysaccharide − endotoxin (ECALPS), and cyclic form (ECACYC). ECA maintains, outer membrane integrity, immunogenicity, and viability of enterobacteria. A supernatant obtained after LPS ultracentrifugation was reported as a source for ECA isolation, but it has never been assessed for detailed composition besides ECACYC. We used mild acid hydrolysis and gel filtration, or zwitterionic-hydrophilic interaction liquid (ZIC®HILIC) chromatography combined with mass spectrometry for purification, fractionation, and structural analysis of rough Shigella sonnei and Escherichia coli R1 and K12 crude LPS preparations. Presented work is the first report concerning complex characteristic of all ECA forms present in LPS-derived supernatants. We demonstrated high heterogeneity of the supernatant-derived ECA that contaminate LPS purified by ultracentrifugation. Not only previously reported O-acetylated tetrameric, pentameric, and hexameric ECACYC have been identified, but also devoid of lipid moiety linear ECA built from 7 to 11 repeating units. Described results were common for all selected strains. The origin of linear ECA is discussed against the current knowledge about ECAPG and ECALPS.

TCR repertoire characteristics predict clinical response to adoptive CTL therapy against nasopharyngeal carcinoma

ABSTRACT The past decade has witnessed the gradual and steady progress of adoptive T cell therapy in treating various types of cancer. In combination with gemcitabine and carboplatin chemotherapy, we previously conducted a clinical trial, NCT00690872, to treat Epstein-Barr virus (EBV)-positive nasopharyngeal carcinoma (NPC) patients with autologous EBV-expanded cytotoxic T lymphocytes (CTLs). While achieving a 2-year overall survival rate of 62.9%, this trial failed to induce an anti-tumor response in a sizable fraction of patients. Thus, the identification of benchmarks capable of evaluating CTL products and predicting clinical immunotherapeutic efficacy remains an urgent need. We conducted T cell receptor (TCR) repertoire sequencing to assess EBV-expanded infusion-ready CTL products. To depict the overall repertoire landscape, we evaluated the individual repertoire diversity by Shannon entropy, and, compared the inter-patient CDR3 similarity to estimate T cells expanded by common antigens. With a recently developed bioinformatics algorithm, termed Motif Analysis, we made a machine-learning prediction of structural regions within the CDR3 of TCRβ that associate with CTL therapy prognosis. We found that long term survivors, defined as patients surviving longer than two years, had a higher CTL repertoire diversity with reduced inter-patient similarity. Furthermore, TCR Motif Analysis identified 11 structural motifs distinguishing long term survivors from short term survivors. Specifically, two motifs with a high area under the curve (AUC) values were identified as potential predictive benchmarks for efficacious CTL production. Together, these results reveal that the presence of diverse TCR sequences containing a common core motif set is associated with a favorable response to CTL immunotherapy against EBV-positive NPC.

Prevalence of Red Blood Cell Alloimmunization Among Beta-Thalassemia and Sickle Cell Anemia Patients: a Study from Saudi Arabia.

The periodic transfusion of red blood cells (RBCs) is an essential supportive therapy for beta-thalassemia and sickle cell anemia (SCA) patients. Nevertheless, this therapy can cause some adverse effects, such as RBC alloimmunization. This study aimed to determine the prevalence of RBC's alloimmunization and frequency of Rhesus (Rh) and Kell (K) antigens among SCA and beta-thalassemia patients in Al-Madinah region of Saudi Arabia. A cross-sectional study was conducted on 137 multiple transfusion patients with SCA and beta-thalassemia, who attended two of the largest hospitals located in Al-Madinah, Saudi Arabia. Demographic and medical data were collected from medical files of patients. Blood samples were collected from patients and Rh and Kell typing were done. Also, antibody screening and identification tests were performed. There were 66 (48.18%) pediatric patients with mean age of 7.8 years, while adult patients were 71 (51.82%) with mean age of 24.5 years. RBC alloantibodies were found in 9 patients (6.57%), and the most frequent alloantibody was anti-K. Antigen e (99.05%) was the most common antigen, while the least common was the antigen K (3.81%). The association between age (pediatric and adult) and alloimmunization rates was insignificant. Although the RBC alloimmunization rate among SCD and beta-thalassemia patients in this study is low compared to other studies in Saudi Arabia and countries all over the world, it still warrants more attention. Phenotyping of donors/recipients' RBCs for K and Rh subgroups may reduce the risk of alloimmunization and increase the efficiency of blood transfusion.

Immunophenotypic aberrancy in acute leukemia – a retrospective single institute study

Introduction: In 2016, WHO gave a comprehensive classification system that included morphology, immunophenotyping, molecular and genetic findings. Flow cytometric immunophenotyping is the backbone of WHO classification, helping to make a more accurate and faster diagnosis. Aim: This study has been conducted to find immunophenotyping aberrancy of acute leukemia (AL) and its association with gender and age group. Material and methods: This is a descriptive retrospective study of 1012 AL patients diagnosed between January 2011 and January 2019, including all new patients of all ages and both sexes, who had available immunophenotyping data. Results and discussion: The most common aberrant antigen on acute myeloid leukemia (AML) was CD7, on precursor B lymphoblastic leukemia (B-ALL) was CD33 and on precursor T lymphoblastic leukemia (T-ALL) was CD13. There was no association between sex/age and antigen aberrancy except a significant increase in CD34 loss on pre B acute lymphoblastic leukemia (pre B-ALL) and HLA-DR expression on acute promyelocytic leukemia (APL) in males compared to female patients and an increase of CD19 expression on non-APL-AML and an elevation of CD34 loss on T-ALL in adult compared to pediatric patients. Not only detection of aberrant expression of CD markers in leukemic cells helps to estimate molecular abnormalities and has a prognostic effect, but also a specification of neoplastic cell markers at the time of diagnosis is essential for monitoring patients after treatment. Conclusions: Although in this study, no association between sex/age and aberrancy of antigens was detected (except in certain AL subtypes), AL specific immunophenotype is essential for minimal residual disease detection.

Prevalence of Kell Blood Group System in Blood Donors of Makkah City, Saudi Arabia.

The Kell blood group system has different types of antigens, which have immunogenic properties; therefore, it is considered as the third clinically significant blood group in blood transfusion. Patients that lack Kell antigen may produce antibodies that may cause transfusion reaction. This study is the first report on Kell antigen system distribution in blood donors in Makkah city which is important to improve transfusion services. Therefore, the aim of the current study is to determine the distribution of Kell antigens and phenotypes among blood donors in Makkah city, Saudi Arabia. This is a retrospective study to determine the prevalence of Kell antigens among blood donors, who come to donate blood in Al Noor specialist hospital, Makkah city. The sample size was 150 donors with a minimum age of 18 years. The most common Kell antigens were k antigen (96%) and Kpb (98%), while the less common were K antigen (18.7%) and Kpa (3.3%). The two most common Kell phenotypes are Kp(a-b+) (95%) and K-k+ (79.3%), while the two least common Kell phenotypes are Kp(a-b-) (1.3%) and Kp(a+b-) (0.6%). This is the first study that set out to determine the prevalence of Kell antigens and phenotypes among blood donors in Makkah city. This study showed that there is a variation in Kell antigen and phenotype distribution. The Kell blood group system has an important impact on transfusion medicine.