Antibody engineering, a strategy for the development of monoclonal antibodies

Advancement in the development of single chain antibodies using phage display technology

Phage display technology has become an important research tool in biological research, fundamentally changing the traditional monoclonal antibody preparation process, and has been widely used in the establishment of antigen-antibody libraries, drug design, vaccine research, pathogen detection, gene therapy, antigenic epitope research, and cellular signal transduction research.The phage display is a powerful platform for technology development. Using phage display technology, single chain fragment variable (scFv) can be screened, replacing the disadvantage of the large size of traditional antibodies. Phage display single chain antibody libraries have significant biological implications. Here we describe the types of antibodies, including chimeric antibodies, bispecific antibodies, and scFvs. In addition, we describe the phage display system, phage display single chain antibody libraries, screening of specific antibodies by phage libraries and the application of phage libraries.

Monoclonal antibody technology for mycotoxins

Specific monoclonal antibodies (MABs) against aflatoxins, ochratoxin A, zearalenone, diacetoxyscirpenol and T-2 toxin have been prepared in various laboratories by the application of hybridoma technology to mycotoxins. These antibodies can be selected for sensitivity, reduced cross-reactivity, reliability and ease of production. When a suitable antibody is chosen it can then be used in a rapid immunological method such as an enzyme-linked or radio-immunoassay or immunoaffinity chromatography system. These assays have a lower limit of mycotoxin detection in the ng/ml range and have been applied to the determination of mycotoxins in samples such as maize, peanuts, peanut butter, milk and porcine kidneys. Using these immunoassay techniques, sample preparation has generally been simplified to a matter of solvent extraction of mycotoxins from the sample followed by dilution; under these conditions, levels of 1-5ug of mycotoxins/kg of sample can be found. The application and advantages of MABs to mycotoxins and the use of these antibodies in various assay techniques is discussed.

Monoclonal antibodies and immobilized antibodies. Patents and literature

Antibodies in both their free and immobilized state have been the object of considerable industrial and academic interest. A variety of methods are used for preparing and immobilizing antibodies. Applications for monoclonal antibodies include the preparation of therapeutics, diagnostics, and in affinity fractionation. Recent US patents on monoclonal and immobilized antibodies and scientific literature on monoclonal antibodies are surveyed. A description of these patents and a list of references are given.

Human and chimpanzee monoclonal antibodies

Monoclonal antibody-secreting cell lines were isolated after transformation of peripheral blood leukocytes with Epstein-Barr virus. Blood samples were obtained from human donors having circulating antibodies against hepatitis viruses (HAB, HBV), rubella, or rabies virus and from a chimpanzee infected with HAV. Dextran-isolated leukocytes were submitted to Epstein-Barr virus infection at low cell concentrations (1 X 10(4) cells X ml-1). Proliferating clones could be observed in 50-100% of the cultures within 4-6 weeks. Out of 1 ml blood (1 X 10(6) leukocytes) 1-10 stable clones were isolated, secreting specific anti-viral antibodies. These clones were fused with an aminopterin-sensitive, ouabain-resistant, non-immunoglobulin producing mouse-human hybridoma (Org MHH.1). From such fusions 10-90% of the cultures yielded viable hybridomas of which 45% produced antibodies with the same specificity as of the parental EBV transformant. Immunoglobulin production of both EBV transformants and hybridomas was shown to be stable for more than 6 months and at a concentration up to 100 micrograms X ml-1 X 48 h-1. Chimpanzee EBV-transformed lymphocytes proliferated excellently in vitro. Mouse-human hybridomas, however, could be more easily cultivated, cloned and scaled up than the parental EBV-transformed lymphocytes. In conclusion, stable, monoclonal antibody-secreting cell lines of either human or chimpanzee origin could be isolated with an efficiency that exceeds by 10-100-fold standard murine hybridoma technology.