Immunoglobulin determination

Raff, M.C., Sternberg, M., Taylor, R.B. (1970). Immunoglobulin determinants on the surface of mouse lymphoid cells. Nature (London) 225,553-554. 

An undoubtedly related phenomenon has been seen with respect to the influence of interchain disulfide bonds on the detection of light-chain-specific and other types of immunoglobulin determinants. It is occasionally observed that the simple reduction of an immunoglobulin, by the inclusion of a mercaptan reductant in the buffer, will facilitate the detec-... 

Preud homme, j. L., Neauport-Sautes, C., Piat, S., Silvestre, D., Kourilsky, F. M. Indepence of HL-A antigens and immunoglobulin determinants on the surface of human lymphoid cells. Europ. J. Immunol. 2, 297-300 (1972). 

The immunoglobulin structure in Figure 6.45 represents the confluence of all the details of protein structure that have been thus far discussed. As for all proteins, the primary structure determines other aspects of structure. There are numerous elements of secondary structure, including /3-sheets and tight turns. The tertiary structure consists of 12 distinct domains, and the protein adopts a heterotetrameric quaternary structure. To make matters more interesting, both intrasubunit and intersubunit disulfide linkages act to stabilize the discrete domains and to stabilize the tetramer itself. 

The Five Types of Heavy Chain Determine Immunoglobulin Class... 

Five classes of H chain have been found in humans (Table 50-7), distinguished by differences in their Cjl regions. They are designated y, a, i 5, and e. The i and e chains each have four domains rather than the usual three. The type of H chain determines the class of immunoglobulin and thus its effector function. There are thus five immunoglobulin classes IgG, IgA, IgM, IgD, and IgE. The biologic functions of these five classes are summarized in Table 50-8. 

In each of the assays of potency the amount of the immunoglobulin and the amount of a corresponding standard preparation that are required to neutralize the infectivity or other biological activity of a defined amount of virus or to neutralize a defined amount of a bacterial toxin are determined. The two determined amounts and the assigned unitage of the standard preparation are then used to calculate the potency of the immunoglobulin in International Units (lU). ELISA, enzyme-linked immunosorbent assay. 

Secondary antibody and determination. A secondary antibody labeled with an enzyme is added which binds to the primary antibody that is bound to the coating antigen. If the primary antibody were produced in a rabbit, an appropriate secondary antibody would be goat anti-rabbit immunoglobulin G (IgG) conjugated with horseradish peroxidase (HRP) (or another enzyme label). Excess secondary antibody is washed away. An appropriate substrate solution is added that will produce a colored or fluorescent product after enzymatic conversion. The amount of enzyme product formed is directly proportional to the amount of first antibody bound to the coating antigen on the plate and is inversely proportional to the amount of analyte in the standards. 

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