Monoclonal antibodies secretion

Other species of hybridomas, including human, have been produced but are generally created by the use of viruses conferring cellular immortality. Artificial immunization of the donor is often not practical or ethical and so cell lines are often derived from peripheral lymphocytes obtained from individuals naturally immune to the target substance. Some human monoclonal antibody secreting cell lines have been derived from spontaneously occurring myelomas, but this line of approach frequently is unrewarding as the probability that the antibody will be one of interest is remote. 

Schneider YJ (1989) Optimisation of hybridoma cell growth and monoclonal antibody secretion in a chemically defined, serum- and protein-free culture medium. 

In 1975, Kohler and Milstein showed that mouse myeloma cells could be fused to B-lymphocytes from immunized mice to generate continuously growing, specific monoclonal antibody-secreting somatic cell hybrids, or hybridoma cells. In the fused hybridoma, the B-cell contributes the capacity to produce a specific antibody, and the myeloma cell confers longevity in culture and the ability to form tumors in animals. 

A B lymphocyte is a specific type of white blood cell (leucocyte) derived from bone marrow stem cells. Each B lymphocyte expresses an immunoglobulin (antibody) specific for a particular antigen. Following antigenic stimulation, a B lymphocyte may differentiate and multiply into plasma cells that secrete large quantities of monoclonal antibody. 

Fig 5 Immunogold labelling on thin sections of low-temperature embedded cell walls from 9-day old tobacco cells with JIM 5, a monoclonal antibody that recognises a relatively unesterified pectic epitope. Cell walls of elongating cells label very weakly, but material that is being secreted into the culture medium labels strongly. The old part of the wall is labelled but new wall material is not. 

TES-32 is the most abundant single protein product secreted by the parasite. It is also heavily labelled by surface iodination of live larvae (Maizels et al., 1984, 1987), and is known by monoclonal antibody reactivity to be expressed in the cuticular matrix of the larval parasite (Page et al, 1992a). TES-32 was cloned by matching peptide sequence derived from gel-purified protein to an expressed sequence tag (EST) dataset of randomly selected clones from a larval cDNA library (Loukas et al., 1999). Because of the high level of expression of TES-32 mRNA, clones encoding this protein were repeatedly sequenced and deposited in the dataset (Tetteh et al., 1999). Full sequence determination showed a major domain with similarity to mammalian C-type (calcium-dependent) lectins (C-TLs), together with shorter N-terminal tracts rich in cysteine and threonine residues. Native TES-32 was then shown to bind to immobilized monosaccharides in a calcium-dependent manner (Loukas et al., 1999). 

Page, A.P., Hamilton, A.J. and Maizels, R.M. (1992a) Toxocara canis. monoclonal antibodies to carbohydrate epitopes of secreted (TES) antigens localize to different secretion-related structures in infective larvae. Experimental Parasitobgi 75, 56-71. 

Dighiero, G., Lymberi, J., Marie, J.C., Rouyse, S., Butler-Browne, G.S., Whalen, R.G. and Avrameas, S. (1983). Murine hybridomas secreting natural monoclonal antibodies reacting with self antigens. J. Immunol. 135 2267-2271. 

Monoclonal antibody, mAb Describes an antibody derived from a single clone of cells or a clonally obtained cell line. Its common use denotes an antibody secreted by a hybridoma cell line. Monoclonal antibodies are used very widely in the study of antigens, and as diagnostics. 

In 1975 G. Kohler and C. Milstein [24] demonstrated that it was possible to generate monoclonal antibodies in vitro. The technique involves cloning a single antibody-secreting B lymphocyte so that uniform antibodies can be obtained in large quantities. 

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