EGFR单克隆抗体抗结肠癌作用的实验研究

目的:观察表皮生长因子受体单克隆抗体(EGFRMcAb)对结肠癌的作用。方法:用不同剂量的EGFRMcAb处理LST174结肠癌细胞系, 采用细胞计数、生长曲线测定及MTT法测定体外培养细胞的生长和增殖抑制率。结果:可见一定程度的增殖抑制并呈剂量依赖性。抗-EGFR抗体组细胞数明显低于对照组(P<0.01).不同浓度之间比较:当EGFRMcAb为0.625mL/L时细胞计数相对高, 是对照组的61.3%;当EGFRMcAb为2.5mL/L时细胞计数最低, 是对照组的33.8%.EGFRMcAb组细胞生长受到抑制, 细胞生长曲线较对照组速度减慢。MTT值显示实验组细胞增殖能力低于对照组, 抑制率为42.3%(P<0.01).结论:EGFRMcAb可抑制人结肠癌LST174细胞生长, 具有一定的抗结肠癌作用。     

Monoclonal antibody against human growth hormone receptor

GHR shows a high degree of homology with the prolactin receptor and with the other receptors that belong to the hemopoietic receptor superfamily. This paper describes a monoclonal antibody (MAb) (2B4B6) specific for both the extracellular domain of human GHR and human growth hormone (GH) binding protein. Mice were immunized against a seven-aminoacid peptide sequence screened by FASTA (sequence similarity search served by Genome-Net) from the European Bioinformatics Institute to exclude the existence of human membrane proteins with significant sequence homology. MAbs were screened against the peptide sequence and 2B4B6 was selected for its capability to recognize the full-length hGHBP. As evaluated by both enzyme-linked immunoadsorbent assay (ELISA) and FACS analysis, this MAb seems to recognize and bind to a hGHR positive cell line, IM-9, as well as a murine cell line, BaF3 (8/6), transfected with a chimeric construct, hGHR/hG-CSFR and expressing hGHR on the cell membrane. Studies investigating the biological effects of this MAb showed that anti-hGHR mediated inhibition of cell proliferation was not due to competition with GH binding but rather to prevention of receptor dimerization. Because of its specificity, this MAb may be usefully applied in situations in which GHR and receptors with a high degree of homology, such as PRLR (prolactin receptor), are expressed simultaneously, as occurs in the immune system.     

抗重组人表皮生长因子单克隆抗体的制备及生物学特性鉴定

目的　制备出高效价的抗重组人表皮生长因子 (EGF)单克隆抗体。方法　以重组人表皮生长因子作为抗原 ,免疫Balb/c小鼠 ,以未免疫的Balb/c小鼠脾细胞为饲养细胞 ,运用细胞杂交瘤技术制备 ,间接ELISA法筛选产生针对人表皮生长因子的单克隆抗体细胞株 ;以体内诱生法产生腹水 ,并采用ProteinA Sepharose柱对其纯化 ,快速定性试纸鉴定McAb的Ig亚类 ,采用间接ELISA法相加实验鉴定抗原识别表位。结果　获得 3株产生针对人表皮生长因子的单克隆抗体细胞株EGF B2 、EGF C7、EGF A8,Ig亚分别为IgG1κ型 ,IgG1λ型 ,IgG3 κ型 ,亲和力常数分别为 2 .76× 10 10 、3.2× 10 9、1.4 5× 10 9。结论　成功制备 3株稳定分泌抗rhEGF的杂交瘤细胞株 ,产生的McAb特异性好 ,亲和力高 ,为探讨EGF的作用机制及临床应用奠定了基础 ,为肿瘤的诊断与治疗提供具有实用价值的研究工具 ,此外 ,为EGF的纯化提供实验材料     

Monoclonal antibody to human cross-linked fibrin

Cross-linked Fibrin II was prepared using Kabi grade (L) fibrinogen. Fibrin plasmic digest was separated on Sepharose CL-6B. Fragments Mr 135-300 kDa were used to immunize 6-9 weeks old female BALB-c mice. A stable hybridoma secreting monoclonal antibody (MAb) TD-1 (IgG 2a, Kappa) was prepared by fusion using myeloma cells (P3-NS1/1-Ag4-1) and immunized cells. Fibrinogen and plasmin digest of fibrinogen in serial dilutions did not compete with the immunizing antigen. To prove that TD-1 binds specifically to cross-linked fibrin, immunoprecipitation with S. aureus and affinity chromatography were performed. In both experiments, we demonstrated that TD-1 binds specifically to a protein Mr greater than 200 kDa which is found in XL-fibrin and not fibrinogen. Reduced samples showed the antibody bands (heavy and light chains) and three protein bands, Mr greater than 80 kDa (gamma-gamma dimer), Mr greater than 45 kDa (beta chain of fragment D) and Mr greater than 16 kDa (alpha chain from fragment D) were present. TD-1 reacted strongly with HPLC fraction of the immunizing antigen Mr 220 kDa (probably DD/E complex). Affinity binding constants (Scatchard Plot Analysis) were determined. The highest affinity was obtained with XL-fibrin fraction Mr 220 kDa, KD = 1.39 X 10(-8) and high molecular weight XL-fibrin fragments, KD = 1.6 X 10(-7). Fragment DD had KD of 2.8 X 10(-6). These results suggest that TD-1 is specific for the DD region of human cross-linked Fibrin II.     

Monoclonal antibody NIM-R3 substitutes for B-cell growth factor.

A rat monoclonal antibody (NIM-R3) was found to be reactive with activated mouse B cells but neither activated T cells nor small resting lymphocytes, T or B. The antibody stains antibody-forming cell precursors within 48 hr of primary or secondary immunization in vivo, but not at longer times (greater than 14 days) immunization. When added to cultures of spleen cells responding in vitro to dinitrophenylated bovine, IgG, the number of antibody-forming cells was increased. NIM-R3 also maintained the proliferation of purified B blasts in the absence of lipopolysaccharide, but did not activate small resting B cells in the presence of anti-Ig. NIM-R3 could replace B-cell growth factor (BCGF II) in cultures of the murine B-cell lymphoma BCL1 inducing proliferation but not differentiation. Finally, competition was demonstrated for binding sites on BCL1 cells between BCGF II and NIM-R3, but not between NIM-R3 and T-cell replacing factor (B15-TRF). We suggest that NIM-R3 may represent a novel specificity and may be directed against the cell surface receptor for BCGF II, and in turn this receptor may be independent of the B15-TRF and BSF1 receptors.     

Monoclonal antibodies against human basic fibroblast growth factor

Recombinant human basic fibroblast growth factor (hbFGF) was used as an antigen to develop, by a somatic cell fusion technique, four monoclonal antibodies (MAbs), that recognize the complete and amino-terminal truncated form of hbFGF. Isotype identification showed that MAbs designated MAb12 and MAb98 were IgG1; and those designated MAb52 and MAb78 were IgG2b. All these MAbs bound the complete form of hbFGF produced in E.coli. Competition with synthetic polypeptides, a replication of 1-9 aa and of 141-146 aa of hbFGF, and truncated forms of hbFGF by 13 and 40 amino acid residues in its amino-terminal produced in E. coli by recombinant technique, revealed at least two epitopes recognized by the four IgG type MAbs. MAb12 and MAb78 recognized the epitope located within the first 9 amino acid residues at the amino terminal of the complete hbFGF. MAb52 and MAb98 recognized the one located between the amino acid residue no. 14 and 40. None of MAbs bound bovine acidic FGF (aFGF). Using MAb52 or MAb98 and MAb78, a two-site EIA has been developed. This EIA is sensitive enough to detect 0.5 ng/ml of hbFGF. Furthermore, MAb78 was used as a ligand for affinity chromatography to purify hbFGF mutein CS4, which binds weakly to a heparin affinity column.     

Gene expression and immunolocalization of heparin-binding epidermal growth factor-like growth factor and human epidermal growth factor receptors in human corpus luteum

BACKGROUND: The objective of this study was to elucidate gene expression and immunolocalization of heparin-binding epidermal growth factor-like growth factor (HB-EGF) and human epidermal growth factor receptor (HER) family in the human ovary during luteal growth and regression. METHODS: Ovaries obtained from pre-menopausal women were used for immunohistochemistry and semiquantitative RT-PCR analysis. RESULTS: Immunoreactive HB-EGF was not detected in follicles or oocyte, while HB-EGF became apparent in granulosa luteal cells in the early luteal phase, and most abundant in the mid-luteal phase, but less abundant in the late luteal phase. Immunostaining for HER1 was very weak in granulosa luteal cells in the early and mid-luteal phases, and was not detected in the late luteal phase. Immunoreactive HER4 was abundant in the early luteal phase and became less abundant in the mid-luteal phase, whereas it was negative in the late luteal phase. Semiquantitative RT-PCR analysis revealed that HB-EGF and HER1 mRNA levels were high in the mid-luteal phase, whereas HER4 mRNA expression was high in the early luteal phase. CONCLUSIONS: HB-EGF may play a vital role in regulating luteal growth in a juxtacrine manner and through activating HER4 signalling.     

Expression of epidermal growth factor in human tissues

Summary The expression of epidermal growth factor (EGF) was examined on various human tissues by radioimmunoassay, immunohistochemistry and Northern blot analysis. Immunoreactive EGF was found in most of the human tissues by radioimmunoassay at various levels. Large quantities of EGF were detected in the kidney and thyroid gland. Immunohistochemically, EGF immunoreactivity was detected mainly in the epithelial cells of the lung, stomach, duodenum, pancreas, kidney, pituitary gland, thyroid gland, mammary gland, ovary, uterus and placenta. Weakly EGF-positive cells were also found in the adrenal gland. The results of EGF-immunostaining were not always consistent with the data from radioimmunoassay. We consider that the amount of EGF measured by radioimmunoassay reflects the density of EGF-positive cells in the tissues and the concentration of EGF in individual EGF-positive cells. Furthermore, EGF mRNA was expressed in the salivary gland, thyroid gland, mammary gland and kidney. It is thus evident that EGF is produced by a variety of human tissues. The kidney expressed exceptionally high levels of EGF mRNA which was about one-tenth of the expression in mouse submandibular gland, suggesting that most of EGF in the urine is produced and secreted by the epithelial cells of renal tubules.     

Transforming growth factor alpha and epidermal growth factor in human pancreatic cancer.

Overexpression of the epidermal growth factor receptor (EGFR) has been reported as an important molecular abnormality in human pancreatic cancer. There is in vitro evidence that simultaneous overproduction of one of its ligands, transforming growth factor alpha (TGF-alpha), might result in an autocrine loop with an increased proliferation signal. We analysed by immunocytochemical staining a retrospective series of human pancreatic cancers, chronic pancreatitis, and normal fetal and adult pancreatic tissues for the presence of TGF-alpha and epidermal growth factor (EGF). Ductal epithelial cells showed TGF-alpha immunoreactivity in both normal tissue and chronic pancreatitis, and 95 per cent of tumours showed strong immunoreactivity. In contrast, EGF immunoreactivity was not found in normal pancreas, but was expressed in 12 per cent of pancreatic carcinomas. Well-defined areas of EGF immunoreactivity in exocrine ducts showing reactive changes in pancreatitis might represent a benign response to tissue damage similar to that previously described in the gastric mucosa.     

Differentiation-related expression of epidermal growth factor receptors in human lung carcinoma demonstrated histochemically by biotinylated epidermal growth factor

Biotin-labeled epidermal growth factor (EGF) was applied to routinely processed sections of 64 cases of human lung carcinoma as a histochemical tool for demonstrating EGF-specific receptors. Formalin-fixed, paraffin-embedded tissue sections were deparaffinized and incubated with the labeled EGF (10 micrograms/ml) for 60 min at room temperature. The specific binding of the growth factor to its receptor was visualized by the avidin-biotin complex (ABC) technique. Positive binding capacities were obtained for the following cases: 15/16 epidermoid carcinoma; 13/15 adenocarcinoma; 2/11 large cell anaplastic carcinoma; 12/20 small cell anaplastic carcinoma; 0/11 normal lung tissue; 0/6 main bronchi; 0/1 hamartoma; 0/1 primary fibrosarcoma of lung. In addition, a strong positive reaction was seen for neutrophilic granulocytes present within the tumorous tissue. Data indicate that EGF receptors are frequently expressed in more differentiated carcinoma in comparison with anaplastic carcinoma of lung.     

Expression of epidermal growth factors and epidermal growth factor receptor in normal cycling human ovaries

Immunolocalization of transforming growth factor- (TGF), epidermalgrowth factor (EGF), cripto-1, amphireg-ulin and epidermal growthfactor receptor (EGFR ) was studied in 51 premenopausal humanovaries at various phases of the menstrual cycle. Localizationof mRNA for TGF and EGF was also studied by in-situ hybridization.Immunoreactive TGF was observed predominantly in theca cellsin 12 of 33 antral follicles in the follicular phase (6/14 dominantfollicles, and 6/19 non-dominant) but not in any of the 18 folliclesin the luteal phase or in primordial and pre-antral follicles.TGF immunoreactivity was present predominantly in the luteinizedgranulosa cells in 13 of 15 corpora lutea in the luteal phase,which are considered to be active in steroidogenesis, but notin any of the regressed corpora lutea. Accumulation of TGF mRNAhybridization signal was observed only in the theca cells inthe follicles and luteinized theca cells in the ovaries thatwere immunohistochemically positive for TGF. EGFR immunoreactivitywas detected in 24 of 33 antral follicles in the follicularphase and in two of 18 follicles in the luteal phase but notin any of the corpora lutea. Immunoreactive EGF, cripto-1 andamphiregulin or EGF mRNA was not detected in any follicles,corpora lutea, or the stroma cells examined. These results indicatethat, of the epidermal growth factors examined in this study,TGF is locally synthesized in normal cycling human ovaries andTGF may be synthesized in theca cells and act on the granulosacells in a paracrine fashion through the EGFR in ovarian follicles. EGF family/human/immunohistochemistry/in-situ hybridization/ovary     

Homologous radioimmunoassay for epidermal growth factor in human saliva

Epidermal growth factor (EGF) is a small polypeptide with potent mitogenic activity. Its synthesis by mouse submaxillary gland is stimulated by certain hormones. To assess its physiological significance in man, we have developed a homologous radioimmunoassay for human epidermal growth factor (hEGF) in saliva. A satisfactory standard curve was readily obtained using either buffer or peptide-free saliva. The mean IC50 was 436 +/- 200 pM (mean +/- SD) and sensitivity approximately 35 pM. The mean normal salivary hEGF in 63 males was 314.6 +/- 21.7 pM (+/- SEM) and 354 +/- 27.8 pM in 48 females. The difference between the means of the sexes was not significant. Assays of aliquots stored under different conditions showed hEGF in saliva to be stable and the method reproducible. Salivary hEGF secretion did not suggest diurnal rhythmicity and was unrelated to meals.     

Heparin-binding epidermal growth factor cleavage mediates zinc-induced epidermal growth factor receptor phosphorylation

We have previously shown that exposure to zinc ions can activate epidermal growth factor (EGF) receptor (EGFR) signaling in murine fibroblasts and A431 cells through a mechanism involving Src kinase. While studying the effects of zinc ions in normal human bronchial epithelial cell, we uncovered evidence for an additional mechanism of Zn(2+)-induced EGFR activation. Exposure to Zn(2+) induced phosphorylation of EGFR at tyrosine 1068, a major autophosphorylation site, in a dose- and time-dependent fashion. This effect of Zn(2+) on EGFR was significantly blocked with an antibody against the ligand-binding domain of the receptor. Neutralizing antibodies against EGFR ligands revealed the involvement of heparin-binding EGF (HB-EGF) in Zn(2+)-induced EGFR phosphorylation. This observation was further supported by immunoblots showing elevated levels of HB-EGF released by Zn(2+)-exposed cells. Zymography showed the existence of matrix metalloproteinase-3 in Zn(2+)-challenged cells. Incubation with a specific matrix metalloproteinase-3 inhibitor suppressed Zn(2+)-induced EGFR phosphorylation as well as HB-EGF release. Therefore, these data support an autocrine or paracrine mechanism whereby Zn(2+) induces EGFR phosphorylation through the extracellular release of EGFR ligands, which may be mediated by metalloproteinases.     

Monoclonal antibody to human basement membrane collagen type IV

We have developed a hybridoma cell line which secretes monoclonal antibody to human basement membrane type IV collagen. The monoclonal antibody secreted by this hybridoma has been obtained in large amounts by either concentrating it from culture supernatants or from the ascites fluid of mice bearing the hybridoma tumour. This monoclonal antibody to type IV collagen does not cross-react with other types of collagens, including types I, III and V, as determined by an enzyme-linked immunosorbent assay (ELISA) and by immunohistochemical staining of corneal and lens sections. Descemet's membrane of mouse, rabbit and human corneal endothelium and lens capsule, both rich in type IV collagen, bind the antibody when stained immunohistochemically. By the indirect precipitation technique, the antibody is found to bind more than three peptides in the basement membrane collagen-rich fraction of human placenta. Based on the observations of other investigators, these peptides are probably derived by proteolysis of the larger polypeptides, since the purification steps in involve extensive pepsin digestion.     

The epidermal growth factor receptor in human pancreatic cancer.

The epidermal growth factor receptor (EGFR) and its ligands are thought to be important in the control of proliferation of many epithelial systems, including the exocrine pancreas. Abnormalities in expression of two of the known ligands of the EGFR, transforming growth factor alpha and epidermal growth factor, occur frequently in ductal adenocarcinoma of the human pancreas. We have examined an archival series of cases of pancreatic pathology for expression of the EGFR using the anti-EGFR antiserum 12E and found that there is almost ubiquitous overexpression of EGFR in pancreatic cancer and in chronic pancreatitis. Southern blot analysis showed no evidence of amplification or rearrangement of the EGFR gene. We conclude that an autocrine loop involving the EGFR system may be involved in the genesis of both neoplasia and reactive hyperplasia of pancreatic ductal epithelium.     

体外重组表达血管生长因子VEGF165单克隆抗体的制备及鉴定

目的:研制人VEGF165单克隆抗体(mAb),为研究VEGF165的生物学活性提供基础.方法:应用RT-PCR从脐静脉内皮细胞中克隆人VEGF165基因,克隆人原核表达载体pGEX-6P1中获得重组表达载体pGEX-6P1 -VEGF165,转化大肠杆菌BL21,经IPTG诱导表达获得重组人VEGF165蛋白,将重组蛋白纯化后免疫BALB/c小鼠,通过杂交瘤技术,制备人VEGF165高效价的mAb.通过鸡胚血管形成抑制实验、HUVEC迁移抑制实验以及HUVEC血管形成抑制实验,对获得的人VEGF165特异性mAb进行进一步鉴定.结果:成功地从脐静脉血管内皮细胞中克隆出人VEGF165基因,并在大肠杆菌表达系统中获得高效表达,以纯化重组蛋白作为免疫原免疫小鼠,筛选获得5株分泌人VEGF165特异性mAb的杂交瘤细胞株,分别命名为5A6、3F5、6H3、7D10、7A10,其中5A6、3F5、6H3、7D10分泌的mAb亚类为IgG2a,7A10分泌的mAb亚类为IgG2b,抗体轻链均为κ链.5株mAb均能抑制鸡胚血管形成、抑制HUVEC迁移和及血管形成.结论:所获得的mAb具有效价高,活性强的优点,为抗肿瘤血管研究中进一步研究VEGF165的生物学作用提供了重要的基础.     

表皮生长因子的研究进展

表皮生长因子具有广泛的促丝裂增殖的作用。本文就其近年来的研究进展 ,包括其分子结构、合成与释放、调控因素、受体 ,以及对神经、消化、呼吸、生殖等多系统的生物学作用等方面的内容作一综述     

Immunolocalization of epidermal growth factor (EGF) in human salivary glands detected with the new monoclonal antibody.

Epidermal growth factor (EGF) is biologically active peptide commonly seen in many human tissues and organs. Its high concentration has been found in the salivary glands. The purpose of the present study was to determine EGF immunolocalization in normal human major salivary glands using a new monoclonal antibody anti-EGF. The results were compared with EGF location determined by using two human antibodies (Oncogene, USA and ICI from dr Gregory, UK). Immunohistochemical studies were performed by the PAP method. All antibodies demonstrated EGF expression in the efferent pathways of the salivary glands, especially in their proximal segments.     

Monoclonal antibody (F5) to human prostate antigen

Hybridoma culture F5 has been developed which secretes monoclonal antibody (McAb) directed to an epitope of a prostatic glycoprotein of Mr 34 kD (Prostate Antigen, PA). Tissue levels of PA have been evaluated using a competitive-binding enzyme-immunoassay based upon the inhibition of McAb binding activity to purified antigen. Results indicated the specific occurrence of high antigen concentrations in extracts prepared from prostatic tissues. The antigenicity of epitope F5 is resistant to tissue fixation and embedding protocols, and has been demonstrated upon immunoperoxidase staining procedures. Immunoperoxidase data strongly indicate that McAb F5 possesses a singular specificity towards prostatic epithelial cells. Other tissues, whether normal or cancerous, fail to express this determinant. Specimens examined included epithelial and nonepithelial tissues along with a panel of carcinomas and sarcomas. The antibody was able to detect tumor cells at extra-prostatic sites and represents a powerful probe for the detection and differential diagnosis of metastatic cancer of the prostate.