异种脱细胞真皮基质抗原性的实验研究

目的　观察不同方法制备的异种脱细胞真皮基质 (Xeno -ADM )埋植物的抗原性差异。　方法　将猪断层中厚皮片采用胰蛋白酶 +tritonX 10 0等处理 ,制成Xeno -ADM ,分为戊二醛交联的Xeno ADM1组、网状交联的Xeno ADM2 组、未交联的Xeno ADM3 组、动物先用Xeno ADM蛋白致敏后再移植交联的Xeno ADM4组和未交联的异体兔Allo ADM对照组。分别将移植物埋植于 5组共计 2 5只日本白兔的耳部和背部皮下 ,术后 2～ 32周检测兔血清抗ADMs抗体效价 ,并观察移植物大体和组织学变化。　结果　Xeno ADM4埋植物组血清抗Xeno ADM蛋白抗体效价最高 ;排除致敏因素的影响 ,Xeno ADM各组血清抗体滴度依次为 :Xeno ADM3 组 >Xeno ADM2 组 >Xeno ADM1组 (P<0 .0 5～ 0 .0 0 1) ;在Allo ADM组中 ,有 4 0 %的血清样本呈现出抗Allo ADM蛋白抗体阳性。组织学上 ,Xeno ADM移植部位有激烈而持久的炎症反应 ,明显强于Allo ADM异体埋植对照组 ;ADM被降解吸收的程度依次为 :Xeno ADM3 >Xeno ADM2 >Xeno ADM4>Xeno ADM1>Allo ADM (P <0 .0 5～ 0 .0 0 1) ,在交联型ADM组易产生异物巨细胞反应。　结论　Xeno ADM的免疫原性强于Allo ADM ,诱导宿主产生IgG限制的免疫反应 ;大张变性的ADM埋植物能降低抗原 抗体反应 ,减缓炎症免疫反应导致的ADM     

第三方未成熟树突状细胞负载异体抗原诱导免疫耐受的实验研究

目的观察第三方未成熟树突状细胞（imDC）负载同种异体抗原后对其免疫特性的影响。方法从健康足月新生儿脐血中分离单核细胞，采用重组人粒细胞巨噬细胞集落刺激因子（rhGM-SCg）和重组人白细胞介素（rhIL）4联合培养7d，诱导其分化成imDC，并通过光学显微镜和扫描电镜观察细胞形态、检测细胞表型及混合淋巴细胞反应（MLR）；将培养的细胞与异体淋巴细胞抗原共同孵育，并给予共刺激分子阻断剂细胞毒性T淋巴细胞相关抗原4免疫球蛋白（CTLA-4Ig）处理，检测抗原负载前后的细胞表型变化，通过MLR比较致敏前后T淋巴细胞增殖的能力。结果（1）培养后细胞具有典型的imDC特征，CD1α、CD83、CD80、CD86等成熟标志呈低表达，分别为21．42％、0．59％、5．39％、3．85％；人类白细胞DR抗原（HLA-DR）的表达率为60．66％，MLR结果提示其不能刺激同种异体T淋巴细胞增殖。（2）负载抗原后的DC表现出成熟特性，CD1α、CD83、CD80、CD86及HLA-DR表达明显增高，分别为65．51％、42．20％、56．45％、38．52％、76．44％（P〈0．05）；能够刺激T淋巴细胞增殖[刺激指数（SI）〉2．00]。（3）给予共刺激阻断剂CTLA-4Ig致耐处理后，SI由2．51下降到0．39。可明显抑制T淋巴细胞增殖。结论第三方imDC负载抗原后能表现出成熟特性；经CTLA-4Ig致耐处理，不能刺激未致敏T淋巴细胞增殖。有望诱导受体针对供者抗原的特异性免疫耐受。     

胃粘膜幽门螺杆菌抗原的分布及其意义

目的 探讨幽门螺杆菌(Hp)感染患者Hp抗原分布部位及其与胃癌的关系。方法 收集经病理学检查证实的Hp 阳性胃病患者共84例 ,用免疫组织化学技术检测胃上皮细胞的Hp 抗原。结果 慢性浅表性胃炎、癌前变化和胃癌患者Hp抗原阳性者分别为12例、22例和13例 ;三者胃上皮细胞胞浆Hp 抗原阳性率依次升高 ,分别为0、63.6 %和84.6% (χ2=19.76,P<0.001) ;12例浅表性胃炎患者Hp抗原位于粘液层及腺颈部以上粘膜9例 (75.0% ) ,22例癌前变化患者Hp抗原位于腺颈部及峡部12例 (54.5% ) ,13例胃癌患者Hp抗原位于峡部以下粘膜9例 (69.2% ,χ2=25.30,P<0.001)。结论 在慢性浅表性胃炎→癌前变化→胃癌的变化过程中 ,Hp抗原逐渐由细胞外向细胞内、由浅表粘膜向深部粘膜迁移。     

Central catecholamine depletion impairs in vivo immunity but not in vitro lymphocyte activation

We have previously shown that depletion of central nervous system (CNS) catecholamines by injecting the neurotoxin 6-hydroxydopamine (6-OHDA) into the cisterna magna of C57B1/6 mice markedly impairs the humoral immune response to sheep red blood cells. This work extends these observations by showing that 6-OHDA treatment also inhibits the humoral antibody response to the T-cell-dependent antigen trinitrophenyl-keyhole limpet hemocyanin, but does not affect the response to the T-independent antigen trinitrophenyl-lipopolysaccharide. This treatment also impairs humoral responsiveness at peripheral lymphoid sites in addition to inhibiting natural killer cell activity. However, 6-OHDA treatment in vivo does not affect in vitro mixed lymphocyte responsiveness, mitogen-induced lymphocyte activation or antigen presentation by macrophages.     

Ia expression and antigen presentation by glia: strain and cell type-specific differences among rat astrocytes and microglia

Astrocytes from experimental allergic encephalomyelitis (EAE)-susceptible Lewis rats expressed higher levels of Interferon-γ-inducible Ia than astrocytes from EAE-resistant Brown Norway (BN) rats, whereas BN microglia expressed higher Ia than Lewis at both mRNA and protein levels. Lewis astrocytes induced proliferation of MBP-specific T cells selected on Lewis background as efficiently as Lewis thymocytes, whereas BN astrocytes were much less efficient in stimulating T cells selected in the presence of BN thymocytes. Microglia, irrespective of strain, induced only weak proliferative responses of these T cells despite the high expression of Ia. Antigen-stimulated T cells underwent apoptosis in the presence of microglia but not astrocytes. Thus, astrocyte-mediated proliferation of MBP-specific T cells may contribute to the development of EAE, while microglia-induced T cell apoptosis may downregulate immunopathological processes in the brain.     

Deficient antigen processing of a protein quaternary structure can be overcome by receptor-mediated uptake

Human chorionic gonadotropin (hCG) is a dimer of non-covalently associated alpha (hCG-α) and beta (hCG-β) subunits. This molecule was used to study whether receptor-mediated uptake influences the presentation of a protein quaternary structure. Unprimed splenocytes and a B cell lymphoma were capable of presenting only the free (hCG-α) but not the combined (hCG) α subunit to hCG-α T cell hybridomas, while hCG-α-primed lymph node cells (LNC) responded to both hCG-α and hCG. As antigen (Ag)-specific antigen-presenting cells (APC) present in the hCG-α-primed LNC population may be potentially effective for presenting hCG, we investigated the role of specific Ag capture, through mIg and FcγR, in the processing and presentation of hCG and hCG-a to HAG 5, a T cell hybridoma directed against the immunodominant region (amino acids 61-81) of hCG-α. Results showed that only B cells bearing membrane immunoglobulin capable of recognizing hCG-α and hCG, and present in hCG-α-primed mice, were extremely effective in presenting the free as well as the combined a subunit. The effect of FcR-mediated uptake was analyzed using a B cell line transfected with the FcγRII-B2 gene to present immune complexes of either hCG-α or hCG. We found that hCG-α and hCG were presented equally well, whatever the Ag-binding site of each antibody to hCG or its a subunit. Using HBG 6, an hCG-β Tcell hybridoma, we performed similar experiments with the FcγRII-B2 cell line and determined that the potentiation of hCG presentation to HBG 6 was similar to that observed with HAG 5. Then kinetic experiments were performed to examine the effect of Ag uptake through FcR on processing. Results demonstrated that the uptake pathway drastically influenced the expression of α T cell determinants in the αβ dimer. In addition, treatment with cycloheximide, a protein synthesis inhibitor, only impaired the ability of APC to present specifically captured Ag. Thus, the processing pathway for specifically captured Ag might be different from the pathway used to process nonspecifically captured Ag. This observation might explain why receptor-enhanced uptake bypasses the inefficient processing of the hCG quaternary structure and enables similar efficiency in the presentation of α and β T cell specificities. These findings provide new insight into the antigenicity of oligomeric molecules, which is modified whether antigen capture is specific or not.     

肾组织中乙型肝炎病毒抗原阳性和阴性IgA肾病的临床与病理对照

目的比较ＩｇＡ肾病（ＩｇＡＮ）肾组织中乙型肝炎病毒抗原（ＨＢＡｇ）阳性和阴性患者的临床与病理特点。方法收集经免疫组化检测证实的肾组织ＨＢＶ抗原阳性组２６例和阴性组５９例ＩｇＡＮ患者的临床和病理及随访资料。结果与阴性组相比，阳性组肾病综合征者多见，血红蛋白、血ＩｇＡ水平和肌酐清除率显著下降，免疫荧光以ＩｇＡ＋ＩｇＧ＋ＩｇＭ型者多见，肾组织病理损害以Ⅳ级为多，肾小球硬化、肾小管病变、间质炎症和纤维化程度均显著严重。两组在临床表现、实验室检查、病理改变及预后方面均有显著性差异，阳性组临床病理改变更严重、预后更差。结论两组是性质相差较大的病变，对阳性组进行抗病毒治疗尤为重要     

华支睾吸虫可溶性抗原对BALB/C鼠免疫效果的研究

用华支睾吸虫成虫可溶性抗原加等量自制佛氏完全佐剂（FCA）免疫BAU3／C鼠，以不同免疫途径、不同时间观察其免疫效果。结果腹腔注射组和皮下多点注射组两次基础免疫间隔3周，第二次基免后两周抗体几何平均滴度分别为2560．00和1470．00，差异无显著性；以加倍剂量于基础免疫后19－122天进行加强免疫，抗体水平迅速提高，于第三天已超过基础免疫水平，但在此时间内进行加强免疫的效果差异无显著性；两次基础免疫间隔3周和4周，其加强免疫后的抗体几何平均滴度分别为5881.34和3044.37，前者优于后者。实验中分别用自制FCA和进口FCA加入可溶性抗原进行免疫，其效果基本一样，但前者制作简便，价廉实用，可取代进口FCA。     

阵发性睡眠性血红蛋白尿患者尿激酶受体的表达及临床意义

目的:检测尿激酶型纤溶酶原激活物受体在阵发性睡眠性血红蛋白尿(PNH)患者中的表达,并探讨其与PNH诊断以及血栓形成的关系。方法:PNH患者22例,其中4例伴血栓形成;单纯心/脑血栓形成患者20例;健康志愿者20例。以流式细胞术检测外周血粒细胞上CD87的表达,ELISA法检测血清可溶性尿激酶受体(su鄄PAR)。结果:健康志愿者外周血CD87 粒细胞比例皆>90%,单纯心/脑血栓形成组与健康志愿者组表达率差异无统计学意义。与其他两组相比,PNH患者外周血CD87 粒细胞百分率显著降低(P<0.01)。PNH组血清su鄄PAR水平显著升高(P<0.01),PNH患者伴血栓形成组与不伴血栓形成组比较,前者外周血CD87 粒细胞比例明显降低,血清su鄄PAR水平显著升高(P<0.01)。PNH患者血清su鄄PAR与CD87 粒细胞百分率呈负相关。结论:PNH患者外周血CD87 粒细胞百分率显著降低,血清su鄄PAR水平明显增高,与血栓形成并发症相关。以流式细胞术检测粒细胞CD87及血清su鄄PAR,有助于PNH的诊断及监测血栓形成的病情变化。     

Dendritic Cells: Tools and Targets for Transplant Tolerance

Our knowledge of the role of dendritic cells (DC) in the generation and maintenance of T-cell tolerance has expanded rapidly and is now a key area of research in basic and applied DC biology. This minireview highlights recent developments in the field that are leading to new avenues for exploiting DC in the promotion of transplant tolerance.