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BackgroundIndividuals with liver disease, and especially those with Hepatitis B or C, are at an increased risk of developing hepatocellular carcinoma (HCC) which is the third most common cause of cancer-related death worldwide. Inadequate screening tests largely account for presentation of advanced tumours and high mortality rates. Early detection of HCC amongst high-risk groups is paramount in improving prognosis. This research aimed to further characterise the previously described humoral immune response raised to tumour-associated antigens (TAAs) in the serum of patients with HCC.MethodsSerum from 96 patients with confirmed HCC, 96 healthy controls matched for age and sex, 78 patients with confirmed liver cirrhosis and 91 patients with confirmed chronic liver disease were analysed for the presence of IgG autoantibodies raised to 41 recombinant TAAs/antigen fragments by ELISA.ResultsVarying autoantibody specificities (97–100%) and sensitivities (0–10%) were observed to individual TAAs. A 21-antigen panel achieved a specificity of 92% and sensitivity of 45% for the detection of HCC. This same panel identified 21% of 169 high-risk controls as having elevated autoantibody levels. A reproducible panel of 10 antigens achieved a specificity of 91% and sensitivity of 41% in HCC. 15% of 152 high-risk controls gave positive results with this panel.ConclusionsThis minimally invasive blood test has the potential to offer advantages over currently available tools for the identification of HCC amongst pre-disposed patients. Results are comparable to current gold standards in HCC (Ultrasonography) and to similar tests in other cancers (EarlyCDT-Lung).

Background-A mouse monoclonal antibody (2C7/IgG2b ) has been described recently, which is directed against the major house dust mite allergen Der p 1, and whose epitope specificity is representative of a major component of the human IgE anti-Der p 1 response. Aims-To characterise an anti-idiotypic antibody (2G10/IgG1 ) raised against monoclonal antibody 2C7 as surrogate human IgE anti-Der p 1. Methods-The specificity of the antiidiotype antibody 2G10 was determined by competitive inhibition experiments using human and mouse immunoglobulins of known V H gene families. The epitope recognised by monoclonal antibody 2G10 was located on the molecular model of the Fv (fragment variable) region of monoclonal antibody 2C7. Results-The data suggest that monoclonal antibody 2G10 is directed against a crossreactive idiotype on human IgE that is shared by polyclonal IgG. Competitive inhibition studies against human immunoglobulins, representative of V H 2, V H 3, and V H 4 gene families, showed that monoclonal antibody 2G10 is mostly likely to be directed against sequences encoded by either V H 3 or V H 4 genes. The fact that monoclonal antibody 2G10 binds to the humanised (complementarity determining region (CDR) grafted) CAMPATH-1H antibody, but not to the original rat CAMPATH-1 YTH34.5.6 antibody, indicates that it is directed against a framework region rather than the CDRs. Analysis of amino acids in the V H region for charge, hydrophobicity, and accessibility suggests that reactivity with monoclonal antibody 2G10 is defined by a hexapeptide spanning residues 74-79 within framework region 3. Conclusion-The anti-idiotype monoclonal antibody 2G10 could potentially be used as a probe for determining the contribution of the V H 3 and V H 4 gene segments to antigenic specificity. We have recently cloned, sequenced, and three dimensionally modelled the V regions of a mouse monoclonal antibody (2C7/IgG2b ) directed against the major house dust mite allergen Der p 1.1 The predicted amino acid sequences were then compared with the V-BASE directory of human germline V gene segments 2-4 and homologous V H and V K gene segments were identified.1 The monoclonal antibody 2C7 heavy chain showed greater than 70% homology with three members of the V H 3 family: Similarly, the light chain showed greater than 70% homology with 11 V K sequences, including the V K II sequences DPK18, DPK19, and DPK28. 4The V-BASE directory contains immunoglobulin gene segments that are commonly found within the human population.2-4 Therefore, it is likely that antibodies similar to monoclonal antibody 2C7 could be generated as part of the human repertoire, particularly when allowing for combinatorial eVects and also somatic mutations of the complementarity determining regions (CDRs) within the rearranged genes. This is very much in keeping with the results of our competition experiments, which showed that the epitope specificity of monoclonal antibody 2C7 is representative of a major component of the human IgE response to Der p 1.

Background: Two mouse monoclonal antibodies have been described, namely: mAb 2C7 (IgG2bκ), which is directed against the major house dust mite allergen Der p 1, and mAb 2G10 (IgG1κ), which is an anti-idiotypic antibody raised against mAb 2C7. Given its broad IgE specificity, anti-idiotype mAb 2G10 could potentially have immunomodulatory applications. For example, a chimaeric human IgG version of mAb 2G10 could prove to be a useful molecule for binding to mast cell and basophil FceRI bound IgE, and in doing so co-ligating FceRI with FcγRIIB, which has been reported to have downregulatory effects. Aims: To produce a chimaeric human IgE version of mAb 2C7 (mAb 2C7huE) and a chimaeric human IgG1 version of its anti-idiotype mAb 2G10 (mAb 2G10huG1). Methods: The Vκ and VH regions of mAb 2C7 and its anti-idiotype mAb 2G10 were engineered into human constant regions of the IgE and IgG1 isotypes, respectively. Results: The production of chimaeric mAb 2C7huE and its anti-idiotype mAb 2G10huG1 confirmed that the respective mouse antibody V regions were successfully engineered into human constant regions and still retained the specificity of the original murine V regions. Conclusion: The newly constructed chimaeric antibodies will be useful to investigate the downregulation of IgE mediated hypersensitivity by the crosslinking of FceRI with FcγRIIB.