Product Catalog

The kit is used for the rapid identification of class, subclass, and light-chain types of mouse monoclonal antibodies (immunoglobulins).

• Reliable: Yields comparable results to the standard ELISA assay
• Fast: 5 min from start to finish
• Easy: Only 3 steps
• Economical: No equipment or additional reagents required
• Highly specific: No crossreactivity with FBS

Assay time: 5 min
Sample material: Hybridoma supernatant, purified mouse monoclonal antibodies, ascites
Specificity: Anti-mouse antibodies, bound to the latex beads, will react with any mouse monoclonal antibody regardless of its isotype.
Goat anti-mouse antibodies, immobilized to the strip, specifically bind to each of the common mouse antibody isotypes (IgG₁, IgG_2a, IgG_2b, IgG₃, IgM, and IgA), and to the light chains.

Early characterization of the isotype of a monoclonal antibody is important for a number of reasons. First, an isotype can determine the simplest method of purification. For example, IgG_2a and IgG_2b bind protein A, whereas IgG₁ monoclonals do not bind protein A very well under standard conditions. Second, some isotypes are better suited to certain immunological techniques than others. For example, IgG_2b antibodies are the best isotype for complement-mediated killing of in vitro cells carrying the epitope. Third, isotype characterization also reveals the structure of the antibody, which may make it undesirable in some applications. For example, IgM exists as a pentamer composed of five 180-kD subunits; therefore, IgM monoclonals are often too large for applications that require monomers. Fourth, an isotype determines the best method for preparing Fab fragments by proteolysis.

1. Development Tubes, contain lyophilized latex beads, precoated with anti-mouse-Ig antibodies
2. Isotyping Strips, precoated with subclass- and light-chain-specific anti-mouse-Ig antibodies

Isotype characterization with the IsoStrip Mouse Monoclonal Antibody Isotyping Kit is made simple by the kit’s two components. Each development tube supplied with the kit contains colored latex beads that bear anti-mouse kappa and anti-mouse lambda antibodies, which will react with any mouse monoclonal antibody regardless of its isotype. The isotyping strip bears immobilized bands of goat anti-mouse antibodies corresponding to each of the common mouse antibody isotypes (IgG₁, IgG_2a, IgG_2b, IgG₃, IgM, and IgA), and to the κ and λ light chains. Both sides of the strip also bear a positive-control band.
The diluted sample is added to the development tube, in which the mouse monoclonal antibody resuspends and forms a complex with the antibody-coated latex beads. When the isotyping strip is placed in the development tube, the complex flows up the strip (via capillary action) until it is bound by the immobilized goat anti-mouse antibody that is specific for the monoclonal’s isotype and light chain.

Figure 1: Test principle.

Figure 2: In the figure, mouse IgG₁, κ is shown. Cutting off the black area at the bottom of the strip is recommended for a permanent record.
Procedure:
1. An antibody-containing sample is pipetted into a development tube, and agitated so that the colored latex beads are completely resuspended.
2. An isotyping strip is placed in the tube.
3. Within 1 - 5 min, a blue band will appear in either the kappa or lambda section of the strip, as well as in one of the class or subclass sections, indicating the class or subclass and light-chain composition of the monoclonal antibody. These blue bands will intensify as the sample moves up the strip. The positive control bands on each side of the isotyping strip should also appear, indicating the antibody-coated latex beads are functional and have traveled up the strip. After 5 min, the results can be interpreted.