1) Assay schemes:
2) Ig G (as antibody isotype)
3) Some classifications:
The secondary antibody has to be directed against the isotype of the primary antibody.
Polyclonal primary antibodies are generally raised in rabbit, goat, sheep or donkey and are an IgG isotype. The secondary antibody will typically be an anti-IgG H&L (Heavy & Light chains) antibody.
Monoclonal primary antibodies are commonly raised in mouse, rabbit and rat. For example, if the primary monoclonal antibody is a mouse IgG1, you will need an anti-mouse IgG or a less specific F(ab) fragment anti-mouse IgG.
Human immunoglobulin classes, subclasses, types and subtypes:
- Classes or isotypes: IgG (γ heavy chains), IgM (μ), IgA (α), IgE (ε), IgD (δ)
- Subclasses: IgG1 (γ1 heavy chains), IgG2 (γ2), IgG3 (γ3), IgG4 (γ4); IgA1 (α1), IgA2 (α2)
- Types: κ light chain, λ light chain
- Subtypes: λ1, λ2, λ3, λ4
Other type of reactivities:
- Polyvalent antibodies react with all classes
- Anti-Fc or heavy chain (α, δ, ε, γ, and μ) antibodies react with heavy chain only
- Anti-F(ab) or whole molecule antibodies react with heavy and light chains independently of the class
- Anti-light chain (κ and λ) antibodies react with all classes since all classes use the same κ and λ light chains