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L G Durrant

Publications and source records attributed to L G Durrant.

At least 37 records · Page 2Linked to original sources
PubMed1999

Increased activation of lymphocytes infiltrating primary colorectal cancers following immunisation with the anti-idiotypic monoclonal antibody 105AD7.

BACKGROUND: The anti-idiotypic monoclonal antibody 105AD7 mimics the tumour associated antigen 791Tgp72, expressed on 70-80% of colorectal cancers. Phase I studies have shown that the vaccine is non-toxic, and a number of patients have been immunised prior to resection of their primary tumours. AIMS: To assess lymphocyte activation at the tumour site by measuring expression of the alpha subunit of the interleukin 2 receptor (CD25). METHODS: Nineteen patients with primary colorectal cancer were immunised with varying doses of 105AD7 prior to resection of their primary tumours. Samples of normal bowel and tumour edge/centre from 16 patients were available for immunohistochemical staining with a monoclonal antibody against CD25. Samples from a matched control group were also stained. Fresh tumours from 14 immunised patients and 31 unimmunised control patients were disaggregated, and the lymphocytes obtained labelled for CD25. Samples were analysed blindly by flow cytometry. RESULTS: Median infiltration of lymphocytes expressing CD25, measured immunohistochemically, was higher in trial patients, as was the ratio of tumour to normal bowel infiltration. Flow cytometric analysis of fresh tumour from immunised patients showed a significantly higher percentage of lymphocytes expressing CD25 tumour infiltrating lymphocytes than their matched and unmatched controls. DISCUSSION: The alpha subunit of the interleukin 2 receptor is increased on tumour infiltrating lymphocytes, in patients immunised with the colorectal cancer vaccine 105AD7. This suggests a population of activated lymphocytes capable of targeting 791Tgp72 expressing tumour cells, such as circulating micrometastases. 105AD7 may have a role as adjuvant therapy in early stage disease.

Aged↗
PubMed1999

Separation of distinct MUC2 mucin glycoforms using two anti-peptide monoclonal antibodies.

Two monoclonal antibodies (MAb996 and MAb994) were produced by immunisation with a synthetic peptide with a sequence based upon that of the protein core of the gastrointestinal MUC2 mucin. The epitopes were identified as T G T Q for MAb996 and P T G T Q for MAb994. Antibody competition tests also confirmed the overlapping nature of the epitopes for the two antibodies. MAb994 and MAb996 were employed in immunoadsorbent columns for the fractionation of human colorectal carcinoma tissue extracts. While the two antibodies displayed only relatively minor differences in immunological specificity and affinity for the immunising synthetic MUC2 mucin core related peptide, they had the capacity to separate antigenically distinct molecules when used as immunoadsorbents. The findings indicated that subfractions of MUC2 antibody-defined mucins exist in human carcinomas and that these may be distinguished by the differential exposure of determinants in the mucin protein core. The results are in accord with the view that aberrant patterns of glycosylation of mucins in human intestinal tumours produces a spectrum of variably glycosylated macromolecules.

Amino Acid Sequence↗
PubMed1998

Colorectal cancer vaccines.

BACKGROUND: Advances in molecular pathology have enabled a number of colorectal cancer antigens to be identified and characterized. The commonest investigated include 17-1A, 791Tgp72 and carcinoembryonic antigen. Vaccines have been developed that stimulate the immune system to target these antigens. This paper reviews current areas of research in this field. METHODS AND RESULTS: Relevant articles were obtained on vaccines for colorectal cancer from Medline and the Bath Information Data System. A number of approaches are currently being evaluated in Phase I, II and III trials. These include anti-idiotypic antibody immunization, DNA vaccines, mucin and heat shock protein-based vaccines, oncogenes and viral vectors. CONCLUSION: Evidence is accumulating to suggest that immune responses may be generated against colorectal cancer using these approaches. While the concept of vaccination against this malignancy is essentially experimental, surgeons should be aware of current advances.

Antigens, Neoplasm↗
PubMed1997

Low doses of 105AD7 cancer vaccine preferentially stimulate anti-tumor T-cell immunity.

Clinical studies with the human anti-idiotypic antibody 105AD7 have clearly shown that 791Tgp72 is a good target antigen for cell-mediated immunity. No antibody-related toxicity was observed in any of the 135 patients entered into phase I/II clinical trials of 105AD7, whereas both helper and cytotoxic T-cell responses were induced. The helper responses were exemplified by induction of interleukin-2 (IL-2), antigen-specific blastogenesis, and enhanced natural killer (NK) activity. Anti-tumor cytotoxicity was measured directly and was supported by activation of circulating CD8 cells. In this study, it is shown that a 100-microgram injection of 105AD7 was more effective than the 200-microgram dose. Enhanced IL-2 production was observed following 15/19 injections of 100 micrograms of 105AD7 whereas only 4/11 injections of 200 micrograms of 105AD7 induced responses (p < 0.02). Similarly, time to progression was significantly (p < 0.05) slower (median 6 m) in patients injected with 100 micrograms than patients receiving the higher dose, suggesting that 100 micrograms or lower may be the optimal dose. The standard dose for hepatitis vaccination is 10 micrograms. In vitro blastogenesis assays on naive donors have shown that a dose of 105AD7, which is either too high or too low, fails to activate T cells. The optimal dose in vitro is 10 ng.

Adult↗
PubMed1997

Cancer vaccines.

A better understanding of immune recognition of cells has led to identification of potential new targets on tumor cells. Noticeable successes in melanoma have been immunization with the GM2 ganglioside vaccine, and the identification of novel antigens such as MAGE, BAGE and GAGE recognized by T cells cloned from cancer patients with regressing disease. However, the unexpected finding that other antigens recognized by these T cells were overexpressed normal differentiation antigens such as tyrosinase. Pmel 17 and Melan A have led to vaccines developed against differentiation antigens expressed in other solid tumors. Monoclonal antibody, anti-idiotype and antigen based vaccines for colorectal target antigens 17-1A, CEA and 791Tgp72 are all in clinical development. Similarly HER2/neu and mucin overexpression in breast cancer represent promising targets. Mutations in tumor oncogenes or suppressor genes which lead to malignant transformation can also present tumor-specific antigens. The most effective vaccines against infectious disease are live viruses. The development of DNA vaccines which act like viruses in entering cells and show continuous production of antigens offers great potential for the future.

Antigens, Neoplasm↗
PubMed1996

Isolation of fetal trophoblasts and nucleated erythrocytes from the peripheral blood of pregnant women for prenatal diagnosis of fetal aneuploides.

We present the results of a study of fetal cell isolation from the peripheral blood of 46 women in the first trimester of pregnancy. The trophoblasts were sorted with paramagnetic beads labelled with a novel monoclonal antibody 340 (Mab340) (Durrant et al., Prenat. Diagn., 14 (1994) 131). This was followed by triple density gradient enrichment to remove maternal lymphocytes and red blood cells. Nucleated red blood cells (NRBC) were sorted by incubation with ferromagnetic particles coated with Mab CD71, an antitransferrin receptor monoclonal antibody, and separation on a mini-MACS column. Sorted cells were sexed using nested PCR for the Y chromosome and the results compared with the karyotypic analysis of the CVS. The sensitivity in determining a male pregnancy with NRBC alone was 38% and with trophoblasts alone was 39%. Sorting for both cell types correctly predicted a male pregnancy in 10/18 or 56%. Of the 10 males correctly identified, 3 were diagnosed on NRBC alone, 3 on trophoblast alone and 4 with both cell types. As there are very few fetal cells in maternal blood, sorting for both will increase the yield and improve diagnosis. However the technique requires further development to improve sensitivity.

Aneuploidy↗
PubMed1996

Cancer vaccines.

Explore the source record for details and available documents.

Antibodies, Anti-Idiotypic↗
PubMed1996

Expression of a peptide epitope of the colonic mucin MUC2 in precursor lesions to gastric carcinoma.

Previous histochemical studies have shown that changes occur in the composition of mucins both in preneoplastic and neoplastic lesions of the gastric mucosa. Since monoclonal antibodies are now available which recognize the protein product of distinct mucin genes, they are likely to provide useful tools for evaluating these changes. Thus, a monoclonal antibody 996/1 raised against a peptide epitope of the colonic mucin MUC2 was examined for its potential as a prognostic indicator in gastric cancer. 996/1 works well on formalin-fixed paraffin sections and shows good staining of the colonic goblet cells in the region of the golgi, while there is no staining of normal control gastric mucosa. The epitope was detected in all cases of intestinal metaplasia (44 samples) and some but not all cases of dysplasia (26 samples) and gastric carcinoma (74 samples). There was no significant difference between the positivity of the tumours according to their classification, stage and lymph node status. These results unfortunately gave little indication that this antibody would be a useful prognostic tool in gastric cancer. However, the pattern of 996/1 staining provides useful information about the molecular changes in mucin expression that occur in gastric carcinogenesis.

Antibodies, Monoclonal↗
PubMed1996

Greater frequency of K-ras Val-12 mutation in colorectal cancer as detected with sensitive methods.

Assays for tumor mutations need to be sufficiently sensitive that a mutation can be readily detected in a high background of wild-type sequence. We have evaluated competitive allele-specific oligonucleotide (cASO) hybridization, the amplification refractory mutation system (ARMS), and a combination of cASO with mutant-enriched polymerase chain reaction (ME-PCR) for their respective sensitivities in detecting the K-ras Val-12 mutation. cASO hybridization detected 1 mutant allele in 100 wild-type alleles and identified 6 of 74 (8%) colorectal tumors as having the Val-12 mutation. ARMS detected 1 mutant in 1000 and 12 of 74 (16%) tumor samples, and the ME-PCR with cASO hybridization detected 1 in 5000 and 20 of 74 (27%) tumor samples. The mutation was not detected in normal bowel mucosa from selected Val-12 tumor-positive patients. ME-PCR combined with cASO resulted in a threefold higher detection rate than has previously been reported and suggests that other studies may have underestimated the frequency of K-ras mutations.

Base Sequence↗
PubMed1995

Induction of cellular immune responses by a murine monoclonal anti-idiotypic antibody recognizing the 791Tgp72 antigen expressed on colorectal, gastric and ovarian human tumours.

There is accumulating evidence that cellular rather than antibody responses are more effective for tumour rejection. It is therefore important to screen anti-idiotypic (anti-id) antibodies for their ability to stimulate anti-tumour T-cell responses. The human anti-id monoclonal antibody (MAb) 105AD7 stimulated both delayed-type hypersensitivity (DTH) responses in animals and antigen-specific blastogenesis and IL-2 induction in advanced cancer patients. It may not be necessary to use human anti-id antibodies as murine anti-id antibodies, which elicit DTH responses against immunodominant human T-cell epitopes and may be just as useful in the clinic. We have therefore produced a murine anti-id antibody to the same MAb as was used to generate the human anti-id antibody and screened it for its ability to generate cellular anti-tumour immune responses. Low-dose immunization with the murine anti-id MAb NCRC60, which recognises the paratope of the anti-791Tgp72 MAb 791T/36, induced DTH responses to 791Tgp72-expressing tumour cells but not to antigen-negative cells. DTH responses with no detectable antibody responses were induced with 5 micrograms of anti-id NCRC60 without adjuvant. Addition of either complete Freund's adjuvant or Quil A did not enhance DTH responses. However, when the anti-id NCRC60 was linked to KLH and injected in the presence of Freund's adjuvant anti-anti-id antibodies and anti-791Tgp72 antibodies were induced. NCRC60 anti-id was also capable in vitro of priming human T cells from cancer patients to proliferate in response to secondary stimulation with 791Tgp72-expressing tumour cells, suggesting that it may have therapeutic potential in cancer patients.

Animals↗
PubMed1995

Clinical evidence that the human monoclonal anti-idiotypic antibody 105AD7, delays tumor growth by stimulating anti-tumor T-cell responses.

A human monoclonal anti-idiotypic antibody, 105AD7, which mimics a colorectal tumor associated antigen, 791Tgp72, has been developed. A Phase I trial in advanced colorectal cancer patients showed that 105AD7 therapy was nontoxic and that immunised patients had prolonged survival when compared to a contemporary group of patients treated in the same center. There is accumulating clinical evidence that 105AD7 delays tumor growth by stimulating anti-tumor T-cell responses. Stimulation of helper T-cells was exemplified in the phase I study as 105AD7 immunized patients showed antigen specific T-cell blastogenesis responses and enhanced IL-2 production. Further evidence was obtained from a new clinical study in which colorectal cancer patients were immunized prior to tumor resection. Immune infiltrating cells were analysed by immunohistochemistry and effector cell function was studied in immune cells from peripheral blood and tumor draining lymph nodes. Both activated CD4 and natural killer (NK) cells were observed at the tumor site, which is of interest as NK cells are rarely found in colorectal tumors. Effector studies confirmed that NK activity was enhanced in 3/6 patients. Increased autologous tumor killing was also found in 3/4 patients and accumulation of CD8RO cells following 105AD7 immunization also suggested that CD8 T cells were being stimulated.

Aged↗
PubMed1994

Enhanced cell-mediated tumor killing in patients immunized with human monoclonal antiidiotypic antibody 105AD7.

A human antiidiotypic monoclonal antibody (105AD7) has been shown to induce antitumor cellular responses in animals and appears to prolong survival in patients with metastatic colorectal cancer without associated toxicity. Proliferative leukocyte responses to the targeted tumor antigen gp72 were observed in these patients and plasma interleukin 2 levels were increased following immunization. Autologous tumor tissue was not available in these patients, so antitumor cytotoxicity could not be measured. This issue has now been addressed in an adjuvant clinical study in primary rectal cancer patients. Six patients with rectal cancer were immunized preoperatively with 105AD7. Peripheral blood lymphocytes taken prior to immunization were tested against tumor cells extracted from biopsies also obtained prior to immunization or from natural killer (NK)-sensitive target cells. Cryopreserved lymphocytes taken before and after tumor immunization, fresh peripheral blood lymphocytes taken immediately prior to surgery, and lymphocytes from tumor-draining lymph nodes were tested against autologous cells from the resected specimen or NK-sensitive target cells. Significant killing of autologous tumor cells, which was not due to NK activity, was seen with cryopreserved lymphocytes or lymph node cells of three patients at 1-2 weeks postimmunization with 105AD7 but not on pretreatment biopsies. Enhanced NK activity was seen 2-3 weeks postimmunization in 3 of 6 patients. These results indicate that 105AD7 human monoclonal antibody immunization enhances cytotoxicity in rectal cancer patients by specific and nonspecific effector mechanisms.

Aged↗
PubMed1994

Clinical outcome of colorectal cancer patients treated with human monoclonal anti-idiotypic antibody.

A human monoclonal anti-idiotypic antibody (105AD7) has been developed which mimics a colorectal-tumour-associated antigen and induces cellular anti-colorectal tumour immune responses in animals. Thirteen patients with advanced colorectal cancer were immunized with 105AD7 and their survival was compared with that of a contemporary group of unimmunized patients with similar disease status. No toxicity related to anti-idiotype immunization was seen. Cellular responses to anti-idiotypic immunization were indicated by lymphocyte proliferation to gp72-positive tumour cells, and production of interleukin-2; anti-tumour antibodies were not detected. Median survival following diagnosis of advanced disease of immunized patients was 12 months, compared with 4 months in unimmunized patients. The improved survival of immunized patients in this study without associated toxicity suggests that 105AD7 immunization may have considerable potential for immunotherapy of colorectal cancer.

Aged↗
PubMed1994

Screening of monoclonal antibodies recognizing oncofetal antigens for isolation of trophoblasts from maternal blood for prenatal diagnosis.

Many monoclonal antibodies have been produced against tumour-associated cell surface antigens for cancer therapy. They have therefore been selected for minimal reactivity with normal tissues and in particular for lack of binding to blood cells or serum components. Many of the antigens recognized are of fetal origin. These monoclonal antibodies may therefore be ideal candidates to recognize and sort fetal trophoblasts from maternal blood for prenatal diagnosis of genetic abnormalities. A panel of 19 anti-tumour antibodies were therefore screened for reactivity with early trimester placenta and two, 340 and 154, were shown to stain trophoblasts. If MAb 340 is linked to magnetic beads, it can efficiently sort trophoblast cell lines from whole blood.

Antibodies, Monoclonal↗
PubMed1994

Production of monoclonal antibodies recognising the peptide core of MUC2 intestinal mucin.

A peptide based on the tandem repeat sequence of MUC2 mucin was used to produce a series of monoclonal antibodies (MAb). The fine specificity of these antibodies and their implications for MUC2 expression are presented. Three of the MAbs, 996/1, 996/7 and 995/25, were specific to the MUC2p and failed to bind to peptides based on the MUC1,3,4 tandem repeat sequences whereas three others, 994/152, 994/91 and 996/36, cross reacted with the MUC2p and the MUC3 tandem repeat peptide but not the MUC1 and MUC4 peptides. An antigen, affinity purified from a colorectal tumour on one of the MUC2p-specific MAbs, 996/1, was shown to be a high molecular weight polydisperse, mucin-like antigen. Two of the MAbs, 996/1 and 994/152, recognised MUC2 in tissue sections, although the fine specificity varied between the two MAbs, with 994/152 strongly staining gastric, ileum and kidney epithelia, and MAb 996/1 intensely staining colon, liver and prostate tissues. These antibodies also stained a colorectal cell line, and MAb 994/152 also stained a gastric and an ovarian cell line. Six of the MAbs were used to stain colorectal tumour and adjacent 'normal' colonic mucosa sections. All six stained normal mucosa, but only two of the MAbs, 996/1 and 994/91, stained tumour tissue. The staining probably reflects exposure of cryptic epitopes due to varying levels of glycosylation in different tissues. These anti-MUC2p MAbs may help in determining the normal role of MUC2 mucin and how it is subverted in malignancy.

Amino Acid Sequence↗