乳腺癌患者血清可溶性Fas、FasL水平的检测

 目的探讨乳腺癌患者血清可溶性Fas(sFas)、可溶性FasL(sFasL)水平的变化及临床意义。方法采用酶联免疫吸附法(ELISA)检测54例乳腺癌患者,20例乳腺良性病变者,18例正常健康志愿者血清中sFas、sFasL的含量,分析两者与乳腺癌临床病理参数的相关性及临床治疗对它们的影响。结果乳腺癌患者血清sFas、sFasL水平高于两对照组,Ⅲ+Ⅳ期高于Ⅰ+Ⅱ期,治疗后低于治疗前(P均<0.05),sFas、sFasL与其他临床病理参数无显著相关性,两对照组血清sFas、sFasL水平无显著性差异(P>0.05)。结论sFas、sFasL可能与乳腺癌的免疫逃逸有关,可作为乳腺癌新的肿瘤标志物     

Initial Study on Immune Escape Mechanism of Mouse Acute Myelomonocytic Leukemic Cell Line WEHI-3

目的研究小鼠急性粒-单核白血病WEHI-3细胞系表面Fas、Fas配体(FasL)、CD80分子表达以及FasL的功能。方法应用流式细胞仪检测WEHI-3细胞表面Fas、FasL、CD80分子表达情况,同时采用氚胸腺嘧啶核苷(3H-TdR)掺入法检测FasL功能。结果WEHI-3细胞表面CD80和Fas表达率分别为5．06％±0．41％、6．75％±2．31％(n=5),但FasL表达率高达63．73％±5．23％(n=5),当WEHI-3(效应细胞,E)和Fas+YAC-1细胞(靶细胞,T)以3:1、10:1和30:1混合培养时,YAC-1细胞的凋亡率分别为26％±4．5％,35％±3．2％和45％±2．7％(n=5)。结论WEHI-3细胞高表达FasL、低表达Fas和CD80,并能诱导Fas+YAC-1细胞凋亡。     

肿瘤免疫学在未来面临的挑战

目前，人类肿瘤免疫学已进入了一个全新的的阶段，开始飞速发展。然而，在未来，肿瘤免疫学仍面临着许多挑战，仍有许多问题需要解决，例如人类肿瘤的抗原性问题，尚未阐明的机体对肿瘤免疫应答的细胞分子机制和免疫监视理论等等。     

Urinary albumin excretion and transcapillary escape rate of albumin in malignancies

Transcapillary escape rate of albumin was determined in 22 patients with different malignancies. In addition, urinary albumin excretion rate was measured in 24-h urine samples using a sensitive immunoassay. Increased urinary albumin excretion was defined as ≥20 μg/min according to conventional standards. Renal glomerular filtration and tubular function was estimated by⁵¹Cr-EDTA plasma clearance and urinary beta 2-microglobulin, respectively. Median urinary albumin excretion rate was 15.0 μg/min (range 6–510 μg/min) and the frequency of increased urinary albumin excretion was 41%. This agrees with other studies showing increased albuminuria in several types of malignant diseases. Patients with advanced disease (tumour, node, metastasis (TNM) stage II–IV) had a significantly higher urinary albumin excretion rate than patients with localized disease (TNM stage I). Serum creatinine, glomerular filtration rate and urinary beta 2-microglobulin were all within normal limits. Median transcapillary escape rate of albumin was 5.5%/h (range 2–8%/h) and this level is comparable with values in healthy subjects. There was no significant difference in transcapillary escape rate between patients with elevated urinary albumin excretion and the normoalbuminuric group. Median value of the absolut outflux of albumin was 10.6 g/h with similar levels in patients with increased urinary albumin excretion and patients with normoalbuminuria. Our results indicate a high prevalence of minor glomerular dysfunction with a slightly elevated urinary albumin excretion in patients with malignancies. The normal endothelial function, as estimated by the transcapillary escape rate of albumin, suggests an overal unaffected capillary permeability and increased urinary albumin loss appears to be an isolated renal phenomenon in cancer patients.     

Plasma volume in acute hypoxia: comparison of a carbon monoxide rebreathing method and dye dilution with Evans' blue

Exposure to acute hypoxia is associated with changes in body fluid homeostasis and plasma volume (PV). This study compared a dye dilution technique using Evans' blue (PV_Evans') with a carbon monoxide (CO) rebreathing method (PV_CO) for measurements of PV in ten normal subjects at sea level and again 24 h after rapid passive ascent to high altitude (4,350 m). Hypobaric hypoxia decreased arterial oxygen saturation to 79 (74–83)% (mean with 95% confidence intervals). The PV_Evans' remained unchanged from 3.49 (3.30–3.68) l at sea level to 3.46 (3.24–3.68) l at high altitude. In contrast PV_CO decreased from 3.39 (3.17–3.61) l at sea level to 3.04 (2.75–3.33) l at high altitude (P < 0.05). Compared with sea level, this resulted in an increase of the mean bias between the two methods [from 0.11 (−0.05–0.27) l at sea level to 0.43 (0.26–0.60) l at high altitude] so that the ratio between PV_Evans' and PV_CO increased from 1.04 (0.99–1.09) at sea level to 1.15 (1.06–1.24) at high altitude (P < 0.05). In conclusion, the two methods were not interchangeable as measures of hypoxia-induced changes in PV. The mechanism responsible for the bias remains unknown, but it is suggested that the results may reflect a redistribution of albumin caused by the combined effects in hypoxia of both an increased capillary permeability to albumin and a decrease in PV. As a result, the small perivascular compartment of albumin beyond the endothelium may increase without changes in the overall albumin distribution volume. Accepted: 31 October 1997     

Early detection of dominant Env-specific and subdominant Gag-specific CD8+ lymphocytes in equine infectious anemia virus-infected horses using major histocompatibility complex class I/peptide tetrameric complexes

Cytotoxic T lymphocytes (CTL) are critical for control of lentiviruses, including equine infectious anemia virus (EIAV). Measurement of equine CTL responses has relied on chromium-release assays, which do not allow accurate quantitation. Recently, the equine MHC class I molecule 7-6, associated with the ELA-A1 haplotype, was shown to present both the Gag-GW12 and Env-RW12 EIAV CTL epitopes. In this study, 7-6/Gag-GW12 and 7-6/Env-RW12 MHC class I/peptide tetrameric complexes were constructed and used to analyze Gag-GW12- and Env-RW12-specific CTL responses in two EIAV-infected horses (A2164 and A2171). Gag-GW12 and Env-RW12 tetramer-positive CD8+ cells were identified in nonstimulated peripheral blood mononuclear cells as early as 14 days post-EIAV inoculation, and frequencies of tetramer-positive cells ranged from 0.4% to 6.7% of nonstimulated peripheral blood CD8+ cells during the 127-day study period. Although both horses terminated the initial viremic peak, only horse A2171 effectively controlled viral load. Neutralizing antibody was present during the initial control of viral load in both horses, but the ability to maintain control correlated with Gag-GW12-specific CD8+ cells in A2171. Despite Env-RW12 dominance, Env-RW12 escape viral variants were identified in both horses and there was no correlation between Env-RW12-specific CD8+ cells and control of viral load. Although Gag-GW12 CTL escape did not occur, a Gag-GW12 epitope variant arose in A2164 that was recognized less efficiently than the original epitope. These data indicate that tetramers are useful for identification and quantitation of CTL responses in horses, and suggest that the observed control of EIAV replication and clinical disease was associated with sustained CTL recognition of Gag-specific epitopes.     

Stress-induced increases in avoidance responding: an animal model of post-traumatic stress disorder behavior?

One prominent symptom of post-traumatic stress disorder (PTSD) is avoidance of stimuli reminiscent of the traumatic event. We attempted to study this aspect of PTSD in two experiments. Groups of rats received forty 3-s tailshocks, or served as home cage controls (HCC). Twenty-four hours later, all subjects received a 4-h session of leverpress escape/avoidance conditioning. In Experiment 1, shock periods in the absence of a response were 1 s; in Experiment 2 they were 30 s. No group differences were observed in Experiment 1. In Experiment 2, previously shocked animals made more avoidance responses and had a higher percent avoidance during the fourth hour of the session than controls. Further, previously shocked animals had a higher efficiency ratio (the percent of responses that were avoidances). No group differences were observed in leverpresses during the safety period (an index of anxiety) in either study. Results are discussed in terms of the effects of stress on avoidance behavior as a potential model for this important feature of PTSD.     

Vaccination with hybrids of tumor and dendritic cells induces tumor-specific T-cell and clinical responses in melanoma stage III and IV patients

Hybrid cell vaccination was developed as therapeutic approach that aims at stimulating tumor-specific cytotoxic T-cell responses in cancer patients using hybrids of autologous tumor and allogeneic dendritic cells. We tested this concept and the efficacy of the vaccines in inducing clinical and immunologic responses in a clinical trial with melanoma stage III and IV patients. Of the 17 patients evaluated, 1 experienced a complete response, 1 a partial response and 6 stable disease with remarkably long survival times. In 11 of 14 patients analyzed, high-frequency T-cell responses to various tumor-associated T-cell epitope were induced and detectable in the peripheral blood. These immune responses were detected in clinical response patients as well as nonresponders. Failures of clinical responses in all the cases investigated correlated with loss of antigen expression and presentation. Hybrid cell vaccination thus proves effective in inducing tumor-specific T-cell responses in cancer patients.     

Chimeric immune receptor T cells bypass class I requirements and recognize multiple cell types relevant in HIV-1 infection

Transduction of T cells with a chimeric immune T cell receptor (CIR) has been proposed as a strategy to generate cellular immunity against viral pathogens such as HIV-1. In the case of the CD4-CD3-zeta chain (CD4-zeta) CIR, specificity for HIV-1 is conferred by binding of the CD4 moiety to gp120 on the surface of infected cells. However, it is unclear whether CD4-zeta-T cells may differ from naturally derived CD8(+) cytotoxic T cells (CTL) in their susceptibility to viral escape mechanisms or ability to recognize different cell types that support viral replication. We demonstrate that CIR-T cells can mediate antiviral activity against HIV-1 in cells that are resistant to class I-restricted CTL-mediated activity. Furthermore, CIR-T cells can suppress virus in multiple cell types, including monocytes, dendritic cells, and lymphocyte-dendritic cell clusters. These results provide evidence that T cells can be redirected against novel targets, and that independence from the class I pathway may have distinct advantages.     

MHC class I-deficient metastatic tumor variants immunoselected by T lymphocytes originate from the coordinated downregulation of APM components

Previous reports from our group indicated that the MHC class I phenotype of metastatic lung colonies produced by a mouse fibrosarcoma tumor clone (B9) were, depending on the immune status of the host, MHC class I negative in immunocompetent mice and MHC class I positive in immunodeficient athymic nude/nude mice. Now we report the identification of the molecular alterations responsible for the changes of MHC class I molecules in both situations. Metastatic nodes were analyzed for the mRNA level of H-2 class I and beta2-microglobulin genes, and several gene components of the major histocompatibility complex (MHC) class I antigen-processing machinery (APM). These included the genes coding for the low-molecular-weight proteins LMP2, LMP7, LMP10, the transporter associated with antigen processing (TAP-1, TAP-2), and calnexin, calreticulin, tapasin, PA-28-alpha, PA-28-beta, ERP-59 and ER-60. Analyses with RT-PCR showed that TAP-1, TAP2, LMP-2, LMP7, LMP10, tapasin and calnexin mRNA specific for these genes was absent in metastases produced in immunocompetent mice. In contrast, similar techniques with mRNA preparations obtained from metastatic nodes from immunodeficient mice showed that the mRNA expression level of these genes was highly positive. Interestingly, the MHC class I-positive or negative phenotypes of the metastatic colonies correlated with in vivo immunogenicity. H-2 positive metastasis grew more slowly than the H-2 negative ones when injected intrafootpat in syngeneic immunocompetent animals and were finally rejected. These results provide evidence of the role of T cells in immune surveillance against tumors and identify a mechanism targeted by antitumor T lymphocytes to generate MHC class I-negative tumor escape variants.