The role of VCAM-l/VLA-4 in the activation of allogenic T cells by murine macrophages

Vascular cell adhesion molecule 1 (VCAM-1) is a member of immunoglobulin superfamily. The principal ligand for VCAM-1 is integrin α4β/VLA-4 (very late antigen 4). It was reported that VCAM-1 was expressed on macrophages and dendritic cells, but little is known about its function on these professional antigen presenting cells (APC). The present study was performed to investigate the expression of VCAM-1 on macrophages and the role of VCAM-l/VLA-4 in the activation of allogenic T cells by murine macrophages. We analyzed VCAM-1 expression on peritoneal macrophages and macrophage cell line J774A.1 by fluorescence-activated cell sorting (FACS). Using neutralizing antibodies, we further analyzed the role of VCAM-l/VLA-4 interaction in macrophage and allogenic T cell mixed lymphocyte reaction (MLR). We found that VCAM-1 was constitutively expressed on macrophages and its expression level was upregulated by soluble tumor associated antigen (freeze-thaw lysates of FBL-3 leukemia cells) and TNF-a. In MLR assays, we observed that blocking VCAM-l/VLA-4 interaction with anti-VCAM-1 or anti-VLA-4 mAbs caused significant inhibition of the proliferative response and IL-2 production. These results suggest that VCAM-lon macrophages not only facilitates the cell-to-cell contact through adhesive interaction but also plays a role in the costimulation of T cells via its interaction with VLA-4 on the T cells. This work was supported by grants from the National Natural Science Foundation of China.No. (39730420). This is one of papers of the special issue on gene therapy research (Chin J Cancer Res Vol. 9 No. 4 December, 1997).     

In Vitro Effects of Retinoids on the Proliferation and Differentiation Features of Epstein-Barr Virus-Immortalized B Lymphocytes

Retinoids have been shown to be effective in the chemoprevention and treatment of certain human malignancies. In this review, we will summarize our recent results concerning the effects of retinoids on the proliferation and differentiation of Epstein-Barr virus (EBV)-immortalized lymphoblastoid B-cell lines (LCLs), an in vitro model of EBV-related lymphoproliferative disorders arising in immunosuppressed hosts. Retinoids proved to be powerful inhibitors of the proliferation of EBV-infected LCLs in vitro, with 13-cis-retinoic acid (RA), all-trans-RA, and 9-cis-RA being the most effective compounds. Of note, retinoid-induced growth arrest in vitro appears irreversible at drug concentrations (10-^-6 mol/L) which may be reached in man after oral systemic therapy. The antiproliferative activity exerted by retinoids on LCLs is a generalized phenomenon usually associated with a progressive accumulation in G₀/G₁ phases of treated cells. The strong upregulation of p27^Kipl invariably observed in cells exposed to retinoids may contribute to the decreased number of cycling cells, probably by inhibiting the transition from the G₁ to S phase. Moreover, we obtained evidence indicating that the antiproliferative effects of retinoids are not dependent on the induction of terminal differentiation of EBV-immortalized B lymphocytes. In fact, the modifications induced by retinoids relative to LCL morphology, phenotype (downregulation of CD19, HLA-DR, and s-Ig, and upregulation of CD38 and c-Ig), and IgM production were highly variable among the lines tested and often only slightly relevant. Finally, the antiproliferative activity exerted by retinoids on LCLs is not mediated by a direct modulation of viral latent antigens, since EBNA-2 and LMP-1 downregulation was a late event detected only in some cell lines. These results indicate that retinoids may be useful in the medical treatment of EBV-related lymphoproliferative disorders of immunosuppressed patients, particularly in the earlier phases of these diseases.     

Sequence Analysis of Genes Encoding Rodent Homologues of the Human Tumor-rejection Antigen SART-1

Human SART-1 ( hSART-1 ) gene encodes a 125 kD protein with a leucine-zipper motif expressed in the nucleus of all proliferating cells, and a 43 kD protein expressed in the cytosol of most epithelial cancers. In this study, two rodent genes ( rSART-1 and mSART-1 ) homologous to hSART-1 were cloned from cDNA libraries of murine brain and a rat tumor cell line, respectively. mSART-1 and rSART-1 were highly homologous to hSART-1 with 86% and 84% identity at the nucleotide level, and 95% and 91% at the protein level, respectively. The leucine zipper domain and two basic amino acid portions that bind DNA, as well as peptide sequences recognized by human cyto-toxic T lymphocytes (CTLs), were all conserved in these rodent genes. Nuclear protein homologous to the 125 kD hSART-1₈₀₀ protein, but not to the 43 kD cytosol SART-1₂₅₉ protein, was detectable with specific antibody in the nuclear fractions of rodent tumor cell lines, and normal rodent fetal liver and testis. These rodent genes should be a novel tool for studies on the biological roles of the SART-1 gene, and also in the construction of animal models of specific immuno-therapy using SART-1 gene products.     

Effects of Interleukin-12 on the Induction of Cytotoxic T Lymphocytes from the Regional Lymph Node Lymphocytes of Patients with Lung Adenocarcinoma

Lung cancer-specific cytotoxic T lymphocytes (CTL) were induced by repeated stimulations of regional lymph node lymphocytes (RLNL) in lung cancer patients with either autologous or HLA-A-locus-matched tumor cells. To investigate the effect of interleukin-12 (IL-12), IL-12 was added during the stimulation of RLNL from HLA A24 / adenocarcinoma patients with either autologous tumor cells or HLA A24-positive adenocarcinoma cells (PC-9) in combination with, or instead of interleukin-2 (IL-2), and then the cytotoxic activity, cytokine production and populations of the lymphocyte subsets were examined. The addition of IL-12, or the substitution of IL-2 by IL-12 was found to enhance the cytotoxic activity and the cytokine production (IFN-γ, GM-CSF) of the CTL as compared with IL-2 alone. The cytotoxic activity and cytokine production were both partially inhibited by anti-MHC-class I monoclonal antibody. The CTL thus induced by IL-12 had a higher proportion of CD3⁺/CD56⁺ cells than the CTL induced with IL-2 alone. The positively selected CD8⁺/CD56^– lymphocytes showed PC-9-specific cytotoxic activity, because the population did not show any cytotoxicity to K562 or A549 (HLA-A26/A30). However, the CD3⁺/CD56⁺ lymphocytes were cytotoxic to both PC-9 and K562. In conclusion, IL-12 is considered to be a useful cytokine for both the induction of lung-cancer specific CTL and the augmentation of non-MHC-restricted cytotoxicity against tumor cells, and may be applicable for adoptive immunotherapy using CTL.     

Sequential T Cell Response Involved in Tumor Rejection of Sarcoma, Meth A, in Syngeneic Mice

We investigated the type of T cell response involved in Meth A tumor rejection in primary immune and hyperimmune syngeneic mice. It was found that a CD4⁺ T cell-mediated delayed-type hypersensitivity (DTH) response activating non-specific killer cells such as macrophages, NK and LAK cells, without a specific CD8⁺ cytotoxic T lymphocyte (CTL) response, was the major immune response leading to Meth A tumor rejection in primary immune mice. In contrast, the specific CD8⁺ CTL response was the major response leading to the tumor rejection, in addition to CD4⁺ T cell-mediated DTH response, in hyperimmune mice. Analysis of CD4⁺ T cell clones established from primary immune and hyperimmune spleen cells indicated that a CD4⁺ T cell clone (C9) of primary immune mice (although only one clone was established) was of Th1 type, and induced cytotoxicity in accessory cells by classic DTH in vitro. Eight CD4⁺ T cell clones were established from hyperimmune spleen cells. Six out of the eight clones were of the Th2 type and two were Th0-like. However, no Th1-type CD4⁺ T cell clone was established from hyperimmune spleen cells. All of these CD4⁺ T cell clones, even the Th2-type clones, were capable of inducing cytotoxicity in vitro in T cell-depleted accessory cells, as in an in vitro DTH response. We postulate on the basis of these results that the T cell response leading to Meth A tumor rejection in vivo sequentially changed from a CD4⁺ T cell-mediated classic DTH response to a CD8⁺ CTL response, in addition to a cellular response mediated probably by Th2-type cells, during the process of repeated immunization.     

白龙片配合化疗治疗中晚期恶性肿瘤的临床研究

目的：为探讨扶正复方中药白龙片配合化疗治疗中晚期癌症的效应及机理。方法：以白龙片配合化疗治疗４１例中晚期肿瘤患者，并与单纯化疗２２例作对照，观察两组化疗完成率、细胞免疫功能等。结果：治疗组化疗完成率（９２．６％，３８／４１例）高于对照组（７７．２％，１７／２２例， Ｐ＜ ０．０５），而毒副反应发生率低于对照组（ Ｐ＜ ０．０５）。治疗组患者 ＣＤ_３和 ＣＤ_４／ＣＤ_８比值升高，说明白龙片对 Ｔ细胞免疫功能有调节作用。结论：白龙片对化疗有减毒增效作用，其调节细胞免疫功能可能是其取得疗效的机理之一。     

重组人催乳素(rhPRL)在huPBL/SCID嵌合模型中对人直肠癌的治疗效应及免疫机理初探

通过体内实验进一步证实rhPRL对机体免疫功能的调节作用,以及用于过继细胞免疫治疗的可能性。我们选用CB17 SCID纯系小鼠,腹腔注入人结肠腺癌细胞(HT29),2小时后腹腔注入尼龙毛纯化的人淋巴细胞(T/NK细胞),同时开始进行rhPRL治疗,并设HBSS对照和rhIL-2治疗对照组。结果表明,rhPRL在体内外均无直接抗癌效应,反而可促进肿瘤生长。当SCID荷瘤鼠同时移植入人的T/NK细胞时出rhPRL可明显提高T/NK细胞的抗癌效果,生存期明显延长(P<0.05)。平均生存期由70.4天延至112.1天,在对照组全部死亡时(d105),rhPRL治疗组有60％存活,且在实验终止时(>160天)仍有40％存活。分析其抗癌机理发现,rhPRL体外可直接促进人T/NK细胞增殖,其分泌上清可抑制肿瘤生长,同时发现人T/NK细胞与HT29共育4小时中rhPRL亦可直接促进杀伤活性。     

T细胞及相关免疫分子在淋巴细胞趋化因子增强肿瘤自杀基因疗法中的作用

本室以往的研究表明,用腺病毒作为载体将大肠杆菌胞嘧啶脱氨酶(CD)基因与小鼠淋巴细胞趋化因子(Itn)基因联合体内转染,具有显著的抗肿瘤效应.本文对其免疫机理进行了进一步研究,发现CT26结肠腺癌细胞体外经过CD/Ltn基因转染并给予前体药物5-FC后,CT26结肠腺癌细胞表达CD80和CD54分子明显增加,提示经CD自杀基因和Ltn基因联转移后,肿瘤细胞免疫原性增加.荷瘤小鼠体内经联合治疗后,小鼠脾细胞分泌IL-2和IFN-γ明显增加.体内用抗CD4、CD8抗体阻断实验研究结果的表明,联合应用自杀基因和Ltn基因治疗主要通过诱导CD8~ T细胞发挥抗肿瘤作用.     

河套大黄非蒽醌类成分研究

从河套大黄干燥根与根茎的甲醇提取物中分得8个非蒽醌类成分。经化学和波谱方法，确定它们的结构分别为：β-谷甾醇（β-sitosterol，Ⅰ）、土大黄苷元（rhapontigeni，Ⅱ）、没食子酸（gallicacid，Ⅲ）、3－（3’，5’-二羟基-反式-肉桂酰基）－5-羟基-△5－α-吡喃酮[3－（3’，5’－dihydroxyl－trans－cinnamoyl）－5－hydroxyl－△5’－α－pyranone，Ⅳ]、胡萝卜苷（daucosterol，Ⅴ）、piceatannol－3’－O-β-D-glucopyranoside（Ⅵ）、土大黄苷（rhaponticin，Ⅶ）和蔗糖（Ⅷ）。其中Ⅳ为一新化合物，命名为波叶素（rheumin）。Ⅰ、Ⅲ、Ⅴ、Ⅵ和Ⅷ系首次从该植物中获得。     

痹康饮治疗类风湿性关节炎的临床随机对照研究

目的:观察痹康饮治疗类风湿性关节炎的临床疗效及对类风湿性关节炎外周血T细胞亚群的影响。方法:将6 0例RA患者随机分为治疗组和对照组,治疗组口服痹康饮;对照组口服甲氨蝶呤、柳氮磺胺吡啶。3个月为1疗程。并检测治疗前后外周血T细胞亚群(另设2 0例健康对照组)。结果:1.两组综合疗效比较:治疗组总有效率93.3% (95 % CI=77.9%～99.2 % ) ;对照组总有效率6 6 .7% (95 % CI=4 2 .2 %～82 .7% ) ;两组综合疗效比较有差异(u =3.815 6 ,P =0 .0 0 0 2 )。2 .两组患者治疗前后T细胞亚群变化:两组治疗后CD4 、CD4 /CD8值均有显著降低,CD8显著升高(P <0 .0 1) ;治疗组治疗后CD4 、CD4 /CD8较对照组有显著降低(P <0 .0 1) ,且接近健康人群。结论:RA患者存在着一定程度的细胞免疫功能紊乱。痹康饮能有效地改善临床症状(OR=0 .14 ,NNT=4 ) ,在一定程度上纠正免疫功能紊乱。