Homogenous antibodies quantities

Because each B-cell clone produces antibody to a single epitope on an antigen, an opportunity exists for producing chemically and functionally homogeneous antibody in substantial quantity. However, the short B-cell lifetime that is determined by normal apoptosis initially made this impractical. However, the discovery by Kohler and Milstein that B cells could be fused with immortal myeloma cells to create hybridomas that can be maintained almost indef-... 

Monoclonal Antibodies (mAB). Exposure to antigens such as those found on bacteria or viruses triggers the production of a lai e number of different antibodies, each of which is specific for a particular molecular determinant on an organism. In the 1960 s, it was discovered that persons with multiple myeloma, a cancer of plasma cells, produced large quantities of homogeneous antibodies. 

In their interaction with saccharides, lectins serve as models for carbohydrate-specific antibodies, with the important advantage that it is possible to purify lectins in gram quantities. Furthermore, lectin combining-sites appear to be homogeneous and noninteracting, in contrast to those of immune antibodies. 

The biochemist interested in testing the function of a specific protein in a complex mixture, such as a tissue homogenate, may use an antibody in the following way. Reactions may be conducted in tw o different test tubes. A typical experiment may involve the study of a reaction that requires the participation of a dozen or so separate proteins. The researcher may place a small quantity of an antibody, known to combine with one of the pnotems, in one (not both) of the test tubes before starting the reaction. To both test tubes the researcher may then add identical quantities of tissue extract and specific salts or reagents that are needed to support the reaction. The researcher then allows 10 minutes to pass in order to allow the accumulation of products. Finally, reactions in both test tubes are terminated, and the amount of product in each test tube is measured. Any difference in the amount of product is justifiably attributed to inactivation of the target protein, in the complex mixture. 

Another crucial development was the finding that the BALB/c (Potter, 1972, 1977a) and later that the NZB strains of mice (Warner, 1975) when injected with paraffin oil develop a disease like multiple myeloma and also often excrete Bence Jones proteins. This not only provided an experimental model, but also permitted detailed comparison of mouse Bence Jones proteins and immunoglobulins with their human counterparts, an indispensable prerequisite for the study of antibody specificity. Relatively enormous quantities (kilograms in some instances) of Bence Jones proteins were obtainable from the urine of patients plasmapheresis yielded substantial quantities of myeloma proteins. Large amounts of the corresponding mouse proteins were also obtainable proteins from such neoplasms were in almost all instances monoclonal and homogeneous. 

Enzyme-Multiplied Immunoassay Technique. EMIT is a homogeneous method for the quantitation of haptens, especially hormones, therapeutic drugs, and drugs of abuse. This method is a competitive assay, in which hapten and enzyme-labeled hapten compete for a fixed, insufficient quantity of antibody (Eq. 6.16). 

---