1-磷酸鞘胺醇受体3参与巨噬细胞迁移及脓毒症诱导的心肌损伤

目的探讨巨噬细胞中1-磷酸鞘胺醇受体(sphingosine 1-phosphate receptor,S1PR)的表达及其作用,观察干预S1PR3(S1P3)对脂多糖诱导的心肌损伤的影响。方法传代培养小鼠Ana-1巨噬细胞,给予脂多糖(lipopolysaccharide,LPS,100 ng/ml)刺激或S1P3特异性抑制剂CAY-10444(10μmol/L)干预,细胞随机分为对照组、LPS组、CAY-10444组、CAY-10444预处理2h+LPS组,Transwell小室观测巨噬细胞迁移,蛋白免疫印迹检测巨噬细胞S1PR的表达,并检测p-Akt/Akt蛋白水平。在体实验,6~8周龄雄性C57/B6小鼠,随机分为对照组、LPS组、CAY-10444组、CAY-10444干预+LPS组,每组12只,LPS(10 mg/kg)腹腔注射,或CAY-10444 1 mg/kg于LPS诱导后30 min腹腔注射干预,24 h后取心脏组织HE染色观察病理改变,免疫组化染色观察巨噬细胞浸润程度以及炎症因子的表达情况,实时荧光定量PCR检测心肌损伤标记分子BNP、巨噬细胞表面分子F4/80、炎症因子TNF-α、IL-1β、IL-6的mRNA水平。结果与对照组比较,LPS诱导巨噬细胞大量迁移S1P3蛋白表达增加(P0.01),p-Akt Ser473/Akt表达上调(P0.01);与LPS组相比,S1P3抑制剂CAY-10444干预后再给予LPS刺激,巨噬细胞迁移被抑制(P0.01),p-Akt Ser473/Akt表达也降低(P0.01);在体实验,LPS诱导小鼠后BNP mRNA水平明显上调(P0.01),同时F4/80以及炎症因子TNF-α、IL-1β、IL-6的mRNA水平上调(P0.01),HE染色可见心肌损伤及炎细胞浸润,免疫组化染色法显示F4/80及炎症因子的大量阳性表达(P0.01);使用S1P3抑制剂后,与LPS组比较,心肌损伤减轻免疫组化中巨噬细胞减少(P0.01),炎症因子表达降低(P0.01),BNP mRNA水平降低(P0.01),F4/80以及TNF-α、IL-1β、IL-6的mRNA水平也明显降低(P0.01)。结论抑制巨噬细胞S1P3表达可抑制巨噬细胞的迁移并提示p-Akt/Akt与了这一过程,此外,S1P3抑制剂的干预可有效减轻LPS诱导的心肌损伤。     

老年2型糖尿病并发ACS患者血清GGT与慢血流-无复流的相关性及其对预后的影响

目的探讨老年2型糖尿病(T2DM)并发急性冠脉综合征(ACS)患者血清γ谷氨酰胺转肽酶(GGT)水平与经皮冠状动脉介入(PCI)治疗术后冠脉慢血流-无复流的相关性及其对预后的影响。方法选取188例诊断为ACS并行急诊PCI的老年T2DM患者,根据TIMI血流分级和校正的TIMI血流帧计数(c TFC)方法评价冠脉血流分为正常血流组(156例)和慢血流-无复流组(32例),分析GGT及其他危险因素与冠脉慢血流-无复流的相关性和主要不良心血管事件(MACE)的发生率。结果慢血流-无复流组的血清GGT水平高于正常血流组[(49±18)U/L vs.(31±13)U/L,P0.01]。相关分析结果显示,血清GGT与冠脉慢血流-无复流呈正相关(r=0.389,P0.01)。血清GGT与PCI术后冠脉慢血流-无复流、住院期间及术后12个月MACE独立相关(分别OR=1.093,95%CI:1.058~1.129,P0.01;OR=1.047,95%CI:1.012~1.082,P0.05及OR=1.058,95%CI:1.028~1.089,P0.01)。结论老年T2DM并发ACS患者血清GGT水平与冠脉慢血流-无复流相关,血清GGT可能是预测冠脉风险的评价指标。     

HBV endemicity in Mexico is associated with HBV genotypes H and G

Hepatitis B virus(HBV)genotypes have distinct genetic and geographic diversity and may be associated with specific clinical characteristics,progression,severity of disease and antiviral response.Herein,we provide an updated overview of the endemicity of HBV genotypes H and G in Mexico.HBV genotype H is predominant among the Mexican population,but not in Central America.Its geographic distribution is related to a typical endemicity among the Mexicans which is characterized by a low hepatitis B surface antigen seroprevalence,apparently due to a rapid resolution of the infection,low viral loads and a high prevalence of occult B infection.During chronic infections,genotype H is detected in mixtures with other HBV genotypes and associated with other co-morbidities,such as obesity,alcoholism and co-infection with hepatitis C virus or human immunodeficiency virus.Hepatocellular carcinoma prevalence is low.Thus,antiviral therapy may differ significantly from the standard guidelines established worldwide.The high prevalence of HBV genotype G in the Americas,especially among the Mexican population,raises new questions regarding its geographic origin that will require further investigation.     

Harnessing the potential of gene editing technology using CRISPR in inflammatory bowel disease

The molecular scalpel of clustered regularly interspersed short palindromic repeats/CRISPR associated protein 9(CRISPR/Cas9) technology may be sharp enough to begin cutting the genes implicated in inflammatory bowel disease(IBD) and consequently decrease the 6.3 billion dollar annual financial healthcare burden in the treatment of IBD. For the past few years CRISPR technology has drastically revolutionized DNA engineering and biomedical research field. We are beginning to see its application in gene manipulation of sickle cell disease,human immunodeficiency virus resistant embryologic twin gene modification and IBD genes such as Gatm(Glycine amidinotransferase, mitochondrial),nucleotide-binding oligomerization domain-containing protein 2, KRT12 and other genes implicated in adaptive immune convergence pathways have been subjected to gene editing, however there are very few publications. Furthermore,since Crohn's disease and ulcerative colitis have shared disease susceptibility and share genetic gene profile, it is paramount and is more advantageous to use CRISPR technology to maximize impact. Although, currently CRISPR does have its limitations due to limited number of specific Cas enzymes, off-target activity,protospacer adjacent motifs and crossfire between different target sites. However,these limitations have given researchers further insight on how to augment and manipulate enzymes to enable precise gene excision and limit crossfire between target sites.     

Abdominal compartment syndrome:Often overlooked conditions in medical intensive care units

Intra-abdominal hypertension(IAH)and abdominal compartment syndrome are well recognized entities among surgical patients.Nevertheless,a number of prospective and retrospective observational studies have shown that IAH is prevalent in about half of the critically ill patients in the medical intensive care units(ICU)and has been widely recognized as an independent risk factor for mortality.It is alarming to note that many members of the critical care team in medical ICU are not aware of the consequences of untreated IAH and the delay in making the diagnosis leads to increased morbidity and mortality.Frequently it is underdiagnosed and undertreated in this patient population.Elevated intraabdominal pressure decreases the blood flow to the kidneys and other abdominal viscera and also results in reduced cardiac output and difficulties in ventilating the patient because of increased intrathoracic pressure.When intraabdominal hypertension is not promptly recognized and treated,it leads to abdominal compartment syndrome,multiorgan dysfunction syndrome and death.Large volume fluid resuscitation is very common in medical ICU patients presenting with sepsis,shock and other inflammatory conditions like pancreatitis and it is one of the major risk factors for the development of intra-abdominal hypertension.This article presents an overview of the epidemiology,definitions,risk factors,pathophysiology and management of IAH and abdominal compartment syndrome in critically ill medical ICU patients.     

Current status of endoscopic retrograde cholangiopancreatography in patients with surgically altered anatomy

Endoscopic retrograde cholangiopancreatography(ERCP)in patients with surgically altered anatomy must be performed by a highly experienced endoscopist.The challenges are accessing the afferent limb in different types of reconstruction,cannulating a papilla with a reverse orientation,and performing therapeutic interventions with uncommon endoscopic accessories.The development of endoscopic techniques has led to higher success rates in this group of patients.Device-assisted ERCP is the endoscopic procedure of choice for high success rates in short-limb reconstruction;however,these success rate is lower in long-limb reconstruction.ERCP assisted by endoscopic ultrasonography is now popular because it can be performed independent of the limb length;however,it must be performed by a highly experienced and skilled endoscopist.Stent deployment and small stone removal can be performed immediately after ERCP assisted by endoscopic ultrasonography,but the second session is needed for other difficult procedures such as cholangioscopy-guided electrohydraulic lithotripsy.Laparoscopic-assisted ERCP has an almost 100%success rate in longlimb reconstruction because of the use of a conventional side-view duodenoscope,which is compatible with standard accessories.This requires cooperation between the surgeon and endoscopist and is suitable in urgent situations requiring concomitant cholecystectomy.This review focuses on the advantages,disadvantages,and outcomes of various procedures that are suitable in different situations and reconstruction types.Emerging new techniques and their outcomes are also discussed.     

Loss of BRCA1 expression leads to worse survival in patients with gastric carcinoma

AIM: To investigate the expression deficiency of key molecular markers in the homologous recombination pathway. METHODS: Expression loss of breast cancer type 1 susceptibility protein (BRCA1), ataxia telangiectasia mutated (ATM), ATM-Rad3-related (ATR), mediator of DNA damage checkpoint protein 1 (MDC1) and meiotic recombination 11 (Mre11) were correlated with their clinicopathological parameters in gastric cancer (GC). One hundred and twenty treatment-naive GC samples were formalin-fixed and paraffin-embedded into tissue blocks. Two representative cores from each block were extracted and constructed into tissue microarrays. Expression levels of BRCA1, ATM, ATR, MDC1 and Mre11 were determined using immunohistochemical analysis, and correlated with clinical parameters, including age, gender, Lauren subtype, tumor grades, clinical stage and overall survival.RESULTS: Expression loss of BRCA1, ATM, ATR, MDC1, and Mre11 was found in 21.4%, 20.2%, 21.0%, 11.1% and 4.6%, respectively, of interpretable cases. BRCA1 loss was significantly associated with patients of diffused subtype (intestinal vs diffused, 8.2% vs 31.7%, P = 0.001), higher tumor grade (Ⅰ/Ⅱ vs Ⅲ, 10.7% vs 20.5;Ⅰ/Ⅱ vs Ⅳ, 10.7% vs 54.5%, P = 0.047) and advanced clinical stage (Ⅰ/Ⅱ vs Ⅲ, 12.9% vs 16.9%;Ⅰ /Ⅱ vs Ⅳ, 12.9% vs 45.5%, P = 0.006). MDC1 loss was significantly associated with patients of diffused subtype (intestinal vs diffused, 0% vs 19.7%, P = 0.001) and higher tumor grade (Ⅰ/Ⅱ vs Ⅲ, 0% vs 12%;Ⅰ/Ⅱ vs Ⅳ, 0% vs 30.8%, P = 0.012). In addition, the survival time of the patients with expression loss of BRCA1 was significantly shorter than those with positive expression of BRCA1 (2-year survival rate, 32.4% vs 62.8%, P = 0.015). No correlations were found between clinicopathological parameters and expression loss of ATM, ATR and Mre11. CONCLUSION: Our results support the hypothesis that homologous recombination deficiency plays an important role in the progression of gastric carcinoma. Loss of expression of BRCA1 and     

Assessment of chronic radiation proctopathy and radiofrequency ablation treatment follow-up with optical coherence tomography angiography: A pilot study

BACKGROUND Chronic radiation proctopathy(CRP) occurs as a result of pelvic radiation therapy and is associated with formation of abnormal vasculature that may lead to persistent rectal bleeding. While incidence is declining due to refinement of radiation delivery techniques, CRP remains one of the major complications of pelvic radiation therapy and significantly affects patient quality of life.Radiofrequency ablation(RFA) is an emerging treatment modality for eradicating abnormal vasculature associated with CRP. However, questions remain regarding CRP pathophysiology and optimal disease management.AIM To study feasibility of optical coherence tomography angiography(OCTA) for investigating subsurface vascular alterations in CRP and response to RFA treatment.METHODS Two patients with normal rectum and 8 patients referred for, or undergoing endoscopic RFA treatment for CRP were imaged with a prototype ultrahighspeed optical coherence tomography(OCT) system over 15 OCT/colonoscopy visits(2 normal patients, 5 RFA-na?ve patients, 8 RFA-follow-up visits). OCT and OCTA was performed by placing the OCT catheter onto the dentate line and rectum without endoscopic guidance. OCTA enabled depth-resolved microvasculature imaging using motion contrast from flowing blood, withoutrequiring injected dyes. OCTA features of normal and abnormal microvasculature were assessed in the mucosa and submucosa. Blinded reading of OCTA images was performed to assess the association of abnormal rectal microvasculature with CRP and RFA treatment, and rectal telangiectasia density endoscopic scoring.RESULTS OCTA/OCT images are intrinsically co-registered and enabled depth-resolved visualization of microvasculature in the mucosa and submucosa. OCTA visualized normal vascular patterns with regular honeycomb patterns vs abnormal vasculature with distorted honeycomb patterns and ectatic/tortuous microvasculature in the rectal mucosa. Normal arterioles and venules < 200 μm in diameter versus abnormal heterogenous enlarged arterioles and venules > 200μm in diameter were visualized in the rectal submucosa. Abnormal mucosal vasculature occurred in 0 of 2 normal patients and 3 of 5 RFA-na?ve patients,while abnormal submucosal vasculature occurred more often, in 1 of 2 normal patients and 5 of 5 RFA-na?ve patients. After RFA treatment, vascular abnormalities decreased, with abnormal mucosal vasculature observed in 0 of 8 RFA-follow-up visits and abnormal submucosal vasculature observed in only and 2 of 8 RFA-follow-up visits.CONCLUSION OCTA visualizes depth-resolved microvascular abnormalities in CRP, allowing assessment of superficial features which are endoscopically visible as well as deeper vasculature which cannot be seen endoscopically. OCTA/OCT of the rectum can be performed in conjunction with, or independently from endoscopy.Further studies are warranted to investigate if OCTA/OCT can elucidate pathophysiology of CRP or improve management.     

Hepatoprotective actions of melatonin: possible mediation by melatonin receptors

Melatonin,the hormone of darkness and messenger of the photoperiod,is also well known to exhibit strong direct and indirect antioxidant properties. Melatonin has previously been demonstrated to be a powerful organ protective substance in numerous models of injury; these beneficial effects have been attributed to the hormone’s intense radical scavenging capacity. The present report reviews the hepatoprotective potential of the pineal hormone in various models of oxidative stress in vivo,and summarizes the extensive literature showing that melatonin may be a suitable experimental substance to reduce liver damage after sepsis,hemorrhagic shock,ischemia/reperfusion,and in numerous models of toxic liver injury. Melatonin’s influence on hepatic antioxidant enzymes and other potentially relevant pathways,such as nitric oxide signaling,hepatic cytokine and heat shock protein expression,are evaluated. Based on recent literature demonstrating the functional relevance of melatonin receptor activation for hepatic organ protection,this article finally suggests that melatonin receptors could mediate the hepatoprotective actions of melatonin therapy.     

Separate calculation of DW-MRI in assessing therapeutic effect in liver tumors in rats

AIM:To explore whether the antitumor effect of a vascular disrupting agent(VDA)would be enhanced by combining with an antiangiogenic agent,and whether such synergistic effects can be effectively evaluated with separate calculation of diffusion weighted magnetic resonance imaging(DW-MRI).METHODS:Thirty-seven rats with implanted liver tumors were randomized into the following three groups:(1)ZD6126,a kind of VDA;(2)ZDTHA,ZD6126 in combination with an antiangiogenic,thalidomide;and(3)control.Morphological DW-MRI were performed and quantified before,4 h and 2 d after treatment.The apparent diffusion coefficient(ADC)values were calculated separately for low b values(ADC low),high b values(ADC high)and all b values(ADC all).The tissue perfusion contribution,ADC perf,was calculated as ADC low-ADC high.Imaging findings were finally verified by histopathology.RESULTS:The combination therapy with ZDTHA significantly delayed tumor growth due to synergistic effects by inducing cumulative tumor necrosis.In addition to delaying tumor growth,ZDTHA caused tumor necrosis in an additive manner,which was verified by HE staining.Although both ADC high and ADC all in the ZD6126and ZDTHA groups were significantly higher compared to those in the control group on day 2,the entire tumor ADC high of ZDTHA was even higher than that of ZD6126,but the significant difference was not observed for ADCall between ZDTHA and ZD6126.This indicated that the perfusion insensitive ADC high values calculated from high b value images performed significantly better than ADC all for the monitoring of tumor necrosis on day 2.The perfusion sensitive ADC perf derived from ADC low by excluding high b value effects could better reflect the reduction of blood flow due to the vessel shutdown induced by ZD6126,compared to the ADC low at 4 h.The ADC perf could provide valuable perfusion information from DW-MRI data.CONCLUSION:The separate calculation of ADC is more useful than conventional averaged ADC in evaluating the efficacy of combination therapy with ZD6126     

Therapeutic polypeptides based on HBV core 18-27 epitope can induce CD8^＋ CTL-mediated cytotoxicity in HLA-A2^＋ human PBMCs

AIM: To explore how to improve the immunogenicity of HBcAg CTL epitope based polypeptides and to trigger an HBV-specific HLA I-restricted CD8^+ T cell response in vitro.METHODS: A new panel of mimetic therapeutic peptides based on the immunodominant B cell epitope of HBV PreS2 18-24 region, the CTL epitope of HBcAg18-27 and the universal T helper epitope of tetanus toxoid (TT) 830-843 was designed using computerized molecular design method and synthesized by Merrifield‘s solid-phase peptide synthesis.Their immunological properties of stimulating activation and proliferation of lymphocytes, of inducing TN1 polarization,CD8^+ T cell magnification and HBV-specific CD8^+ CTL mediated cytotoxicity were investigated in vitro using HLA-A2^+ human peripheral blood mononuclear cells (PBMCs) from healthy donors and chronic hepatitis B patients.RESULTS: Results demonstrated that the therapeutic polypeptides based on immunodominant HBcAg18-27 CTL,PreS2 B- and universal TN epitopes could stimulate the activation and proliferation of lymphocytes, induce specifically and effectively CD8+ T cell expansion and vigorous HBVspecific CTL-mediated cytotoxicity in human PBMCs.CONCLUSION: It indicated that the introduction of immunodominant T helper plus B-epitopes with short and flexible linkers could dramatically improve the immunogenicity of short CTL epitopes in vitro.     

HBcAg-pulsed dendritic cell vaccine induces Th1 polarization and production of hepatitis B virus-specific cytotoxic T lymphocytes

Aim:  Dendritic cells (DCs) pulsed with HBsAg efficiently reverse the immune tolerance to hepatitis B virus (HBV) and induce HBV-specific cytotoxic T lymphocyte (CTL) responses in transgenic mice and healthy volunteers. However, it is not clear whether HBV core antigen (HBcAg)-pulsed DCs can effectively induce CD4⁺ helper T cells polarization into Th1, which contribute to the induction and maintenance of HBV-specific CD8⁺ T cells in chronic hepatitis B (CHB) patients. To address this issue, we conducted this study and investigated whether HBcAg-pulsed DCs could polarize Th1 cells and induce an HBcAg-specific CTL response.
Methods:  HBcAg-pulsed DCs were generated from 21 CHB patients. The capacity of the HBcAg-pulsed DC vaccine to stimulate CD4⁺ and CD8⁺ T cells to produce IFN-γ and IL-4 was estimated by intercellular cytokine staining, and the HBcAg-pulsed DCs derived from 10 humam leucocyte antigen (HLA)-A2⁺ CHB patients were tested for the induction of HBV-specific CTLs from autologous T cells by pentamer staining. The cytotoxicity of these CTLs was evaluated in vitro by flow cytometry.
Results:  The HBcAg-pulsed DCs derived from CHB patients exhibited a stronger capacity to stimulate autologous CD4⁺ and CD8⁺ T cells to release IFN-γ rather than IL-4, which could induce HBV core 18-27 specific CTLs, suggesting a specific cytotoxicity against T2 cells that had been loaded with the HBV core 18-27 peptide in vitro .
Conclusion:  HBcAg-pulsed DC vaccine derived from CHB patients efficiently induced autologous T cell polarization to Th1 and generation of HBV core 18-27 specific CTLs.     

A CTL epitope from human cytomegalovirus IE1 defined by combining prediction of HLA binding and proteasomal processing is the target of dominant immune responses in patients after allogeneic stem cell transplantation

OBJECTIVE AND METHODS: In an attempt to define HCMV IE1-derived, HLA-A(*)0201-restricted epitopes, an advanced computer-based epitope prediction combining HLA binding and proteasomal cleavages in silico was performed. RESULTS: This prediction algorithm clearly confirmed VLEETSVML to be the most likely CTL epitope. By tetramer staining, HCMV pp65 NLVPMVATV-specific CD8(+) T cells were detectable in 18/24 HCMV seropositive HLA-A(*)0201-expressing individuals (median frequency 0.58%; range 0.1%-4.7%), and IE1 VLEETSVML-specific CD8(+) T cells in 5/24 (median frequency 2.1%; range 0.1%-4.3%), respectively (p<0.01). Also in recipients of an allogeneic SCT, VLEETSVML- and NLVPMVATV-specific CD8(+) T cells were detectable in comparable frequencies, but again the number of patients with detectable pp65-specific CD8(+) T cells was higher (p=0.014). In 4/15 individuals, all demonstrating IE1 VLEETSVML-specific CD8(+) T cells prior to peptide stimulation, VLEETSVML-specific T cell lines (purity of 42.6%-98.6% of all CD3(+)/CD8(+) T cells) were successfully generated after 2-4 weeks of culture using the IFN-gamma secretion assay. CONCLUSION: In conclusion, this novel prediction strategy efficiently predicted an immunodominant viral T-cell epitope.     

Lamivudine treatment can overcome cytotoxic T-cell hyporesponsiveness in chronic hepatitis B: new perspectives for immune therapy

The hepatitis B virus (HBV) cytotoxic T lymphocyte (CTL) response in patients with chronic HBV infection is generally weak or totally undetectable. This inability to mount protective CTL responses is believed to be a crucial determinant of viral persistence, and its correction represents an important objective of immune therapies for chronic hepatitis B. However, amplification of CTL responses in vivo may be ineffective if HBV-specific CD8 cells are either absent or nonresponsive to exogenous stimulation. In this study, we asked whether antiviral treatments able to inhibit viral replication and to reduce viral and antigen load can successfully reconstitute CTL responses creating the appropriate conditions for their therapeutic stimulation. For this purpose, the HBV-specific CTL response before and during lamivudine therapy was studied longitudinally in 6 HLA-A2-positive patients with HBeAg+ chronic hepatitis B. Both HBV-specific cytotoxic T cell activity measured by chromium release assay on peptide stimulation in vitro and CD8+ T cell frequency measured ex vivo by HLA-A2/peptide tetramer staining were significantly augmented by lamivudine therapy. This enhancement followed the reconstitution of CD4 reactivity and the decline of viral load induced by therapy. Our study shows that lamivudine treatment in chronic hepatitis B can restore CTL reactivity, making CTL susceptible to exogenous stimulation. This effect may enhance the probability that T cell-based immune therapies delivered after lamivudine treatment can successfully reconstitute a protective CTL response able to cure chronic HBV infection.     

Systematic identification of immunodominant CD8+ T-cell responses to influenza A virus in HLA-A2 individuals

Immunodominant T-cell responses are important for virus clearance. However, the identification of immunodominant T-cell peptide + HLA glycoprotein epitopes has been hindered by the extent of HLA polymorphism and the limitations of predictive algorithms. A simple, systematic approach has been used here to screen for immunodominant CD8(+) T-cell specificities. The analysis targeted healthy HLA-A2(+) donors to allow comparison with responses to the well-studied influenza matrix protein 1 epitope. Although influenza matrix protein 1 was consistently detected in all individual samples in our study, the response to this epitope was only immunodominant in three of eight, whereas for the other five, prominent CD8(+) T-cell responses tended to focus on various peptides from the influenza nucleoprotein that were not presented by HLA-A2. Importantly, with the four immunodominant T-cell epitopes identified here, only one would have been detected by the current prediction programs. The other three peptides would have been either considered too long or classified as not containing typical HLA binding motifs. Our data stress the importance of systematic analysis for discovering HLA-dependent, immunodominant CD8(+) T-cell epitopes derived from viruses and tumors. Focusing on HLA-A2 and predictive algorithms may be too limiting as we seek to develop targeted immunotherapy and vaccine strategies that depend on T cell-mediated immunity.     

Novel epitope evoking CD138 antigen-specific cytotoxic T lymphocytes targeting multiple myeloma and other plasma cell disorders

The development of an immunotherapeutic strategy targeting CD138 antigen could potentially represent a new treatment option for multiple myeloma (MM). This study evaluated the immune function of CD138 peptide-specific cytotoxic T lymphocytes (CTL), generated ex vivo using an HLA-A2-specific CD138 epitope against MM cells. A novel immunogenic HLA-A2-specific CD138(260-268) (GLVGLIFAV) peptide was identified from the full-length protein sequence of the CD138 antigen, which induced CTL specific to primary CD138(+) MM cells. The peptide-induced CD138-CTL contained a high percentage of CD8(+) activated/memory T cells with a low percentage of CD4(+) T cell and naive CD8(+) T cell subsets. The CTL displayed HLA-A2-restricted and CD138 antigen-specific cytotoxicity against MM cell lines. In addition, CD138-CTL demonstrated increased degranulation, proliferation and γ-interferon secretion to HLA-A2(+) /CD138(+) myeloma cells, but not HLA-A2(-) /CD138(+) or HLA-A2(+) /CD138(-) cells. The immune functional properties of the CD138-CTL were also demonstrated using primary HLA-A2(+) /CD138(+) cells isolated from myeloma patients. In conclusion, a novel immunogenic CD138(260-268) (GLVGLIFAV) peptide can induce antigen-specific CTL, which might be useful for the treatment of MM patients with peptide-based vaccine or cellular immunotherapy strategies.     

Efficient identification of HLA-A*2402-restricted cytomegalovirus-specific CD8(+) T-cell epitopes by a computer algorithm and an enzyme-linked immunospot assay

Antigenic peptides recognized by virus-specific cytotoxic T lymphocytes (CTLs) are useful tools for studying the CTL responses exclusively among those who own the major histocompatibility complex (MHC) class I molecules that present the peptides. For widening the application, an efficient strategy to determine such epitopes in the context of a given MHC is highly desirable. A rapid and efficient strategy is presented for the determination of CTL epitopes in the context of given MHC molecules of interest through multiple screenings consisting of a computer-assisted algorithm and MHC stabilization and enzyme-linked immunospot assays. A major cytomegalovirus (CMV)-specific CTL epitope, QYDPVAALF, in the amino acid sequence of its lower matrix 65 kd phosphoprotein (pp65) presented by HLA-A*2402 molecules was identified from 83 candidate peptides. The results indicate that the CMV-specific CTL response is highly focused to pp65 in the context of HLA-A*2402. Endogenous processing and presentation was confirmed using a peptide-specific CD8(+) T-cell clone as the effectors and autologous fibroblast cells infected with recombinant vaccinia virus expressing pp65 gene or CMV as antigen-presenting cells. Flow cytometric analysis of intracellular interferon-gamma production revealed 0.04% to 0.27% of CD8(+) T cells in peripheral blood of HLA-A24(+) and CMV-seropositive donors to be specific for the peptide. The tetrameric MHC-peptide complexes specifically bound to the reactive T-cell clone and 0.79% of CD8(+) T cells in peripheral blood from a seropositive donor. The peptide could be a useful reagent to study CTL responses to CMV among populations positive for HLA-A*2402.     

Direct ex vivo analysis of hepatitis B virus-specific CD8(+) T cells associated with the control of infection

BACKGROUND & AIMS: Cytotoxic T cells have been suggested to be responsible for lysis of hepatitis B virus (HBV)-infected hepatocytes and control of virus infection. The frequency, kinetics, phenotype, and capacity for clonal expansion of circulating HBV-specific CD8 cells were analyzed directly in patients with acute HBV infection to clarify their pathogenetic role. METHODS: Three HLA-A2 peptide tetramers able to visualize HBV core, envelope, and polymerase epitope-specific cytotoxic T lymphocytes were synthesized and used for flow cytometric analysis of antigen-specific populations. RESULTS: Tetramer-positive cells specific for the core 18-27 epitope were found at a higher frequency than those specific for polymerase 575-583 and envelope 335-343 epitopes in most patients with acute HBV. The number of HBV-specific CD8 cells was highest during the clinically acute stage of infection and decreased after recovery. These cells expressed an activated phenotype and had an impaired capacity to expand in vitro and to display cytolytic activity in response to peptide stimulation. Recovery of these functions was observed when the frequency of specific CD8 cells decreased, coincident with a progressive decrease in their expression of activation markers. CONCLUSIONS: This study provides the first ex vivo evidence that the highest frequency of circulating HBV-specific CD8 cells coincides with the clinically acute phase of hepatitis B. These cells exhibit an activated phenotype with limited further proliferative capacity that is restored during recovery.     

Identification of hepatitis B virus-specific CTL epitopes presented by HLA-A*2402, the most common HLA class I allele in East Asia

BACKGROUND/AIMS: The aim of this study was to identify and characterize hepatitis B virus (HBV)-specific cytotoxic T lymphocytes (CTL) epitopes presented by human leukocyte antigen (HLA)-A*2402, most common HLA class I allele in East Asia. METHODS: HLA-A*2402-restricted CTL epitopes were identified by reverse immunogenetics. Immunogenecity of these epitopes was investigated using peripheral blood mononuclear cell (PBMC) from HLA-A24+ patients with acute hepatitis B. RESULTS: An HLA-A*2402 stabilization assay demonstrated that 36 of 63 HBV peptides carrying HLA-A*2402 anchor residues have high- and medium-HLA-A*2402 binding affinity. Two (C117-125 and P756-764) of the 36 peptides induced peptide-specific CTLs. CTL clones and lines specific for these peptides killed HBV recombinant vaccinia virus-infected target cells expressing HLA-A*2402, indicating that these two peptides are CTL epitopes presented by HLA-A*2402. These two peptides were able to induce specific CTLs in 7 and 11 of 12 HLA-A24+ patients with acute hepatitis B, respectively. CONCLUSIONS: We identified two immunodominant CTL epitopes restricted by HLA-A*2402. Because HLA-A*2402 is the most common allele in East Asia, a region in which there are approximately 200 million HBV carriers, these epitopes will be useful for analysis of CTL responses in patients from East Asia.