It is critical to select the appropriate product in accordance with assay requirements. The information provided below is intended to guide the user in selecting the appropriate antibody.
Anti-Heavy and Light Chain (H+L) Antibodies
Antibodies to IgG heavy and light chain (H+L) recognize epitopes on both heavy and light chains of IgG and may react with other immunoglobulins classes that have light chains in common with IgG. The anti-IgG (H+L) antibodies are tested for reactivity to IgG. The extent to which they react with other immunoglobulin classes is not tested and may vary from one lot to another. Antibodies to IgG (H+L) are widely used for detecting IgG in serological immunoassays where broad immunoglobulin reactivity is desirable.
Anti-Heavy Chain Specific Antibodies
Anti-heavy chain specific antibodies, IgG, IgM, IgA, and IgE, react specifically with the heavy chain indicated in the product name. Reactivity with other immunoglobulin classes is minimized through affinity chromatography. Heavy chain specific antibodies are adsorbed against the whole antibody molecule of other immunoglobulin classes to remove shared heavy and light chain reactivity. For example, gamma-specific products are cross-adsorbed on resins containing species-specific IgM and IgA antigens. Anti-heavy chain specific antibodies are useful for quantitation of the exact heavy chain class of antibody in samples containing other immunoglobulins and proteins such as serum or tissue culture media. Anti-heavy chain antibodies are also used to improve sensitivity and specificity of serological assays.
Anti-IgG+IgM (H+L) Antibodies
Antibody products directed against IgG and IgM (H+L) contain an equal mixture of two antibodies that recognize reactive sites specific for IgG and IgM. Every product lot is tested for reactivity to IgG and IgM. The level of reactivity that may occur to other immunoglobulin classes through shared light chain activity is not tested. These products are recommended for use in assays where reproducible detection of both IgG and IgM is desired.
Anti-IgA+IgG+IgM (H+L) Antibodies
Antibodies directed against IgA+IgG+IgM (H+L) contain an equal mixture of three antibodies that recognize reactive sites specific to IgA, IgM and IgG. Other shared sites through light chain cross-reactivity may also be present. Every product lot is tested for reactivity to each of these three immunoglobulin classes. These products are best used when measurement of all three classes of antibodies needs to be controlled in an immunoassay.
F(ab')2 Fragment Affinity Purified Antibodies
F(ab')2 fragment antibodies are specifically developed to enhance signal in assays where the presence of Fc receptor on cells can nonspecifically bind to whole antibody molecules. F(ab')2 antibodies can also be used to reduce background in assays which involve bacterial contamination, and to increase sensitivity in immunohistochemical applications where smaller antibody molecules are needed to diffuse through tissues.
Antibodies are often used in assays where proteins from human or other animal species are present. To minimize nonspecific reactivity to serum components, select antibodies are passed over an affinity column containing immobilized serum proteins. Select antibodies that have been serum adsorbed are labeled as human serum adsorbed (HSA), rat serum adsorbed (RtSA), or rabbit serum adsorbed (RbSA).