Bovine Anti-Goat IgG (H+L)
(min X Bov, Ck, GP, Sy Hms, Hrs, Hu, Ms, Rb, Rat Sr Prot) (05-07-07)

Bovine serum albumin (BSA) and dry milk are used extensively for blocking non-specific binding of antibodies and for stabilizing antibodies and other proteins during freeze drying and in dilute solutions. However, dry milk and most commercial sources of BSA contain bovine IgG which interferes with the use of any anti-goat IgG (as well as anti-sheep IgG) secondary antibodies. When BSA or dry milk are used for blocking, any bovine IgG which binds to a tissue or substrate surface will be labeled by anti-goat IgG. This background labeling may lead to false interpretations or needless repetition of experiments. Similarly, BSA and dry milk in antibody diluents may form immune complexes between the bovine IgG and anti-goat IgG, thus lowering antibody titer and creating backgound from unbound bovine IgG remaining in the diluent. Also, bovine IgG bound to cells after they are cultured in media containing fetal calf serum may result in background labeling on cell surfaces and on Western blots of cell lysate proteins.

The reason for this problem is the close phylogenetic relationship between cows and goats. Anti-goat IgG reacts so completely with bovine IgG that it is economically unfeasible to create by solid phase adsorption an anti-goat IgG which does not cross-react with bovine IgG. Our new bovine anti-goat IgG (H+L) was created by immunizing a cow host with goat IgG. By recognizing only non-self epitopes on goat IgG, the cow host was able to produce anti-goat IgG which inherently had minimal reactivity for bovine IgG.

Whole IgG Affinity-Purified Antibodies

Anti-IgG, Light Chain Specific for Western Blotting (02-12-07)

Following last year's introduction of our new Anti-Rabbit IgG, Light Chain Specific antibodies for Western blotting, we are now offering in addition Anti-Mouse IgG, and Anti-Rat IgG, Light Chain Specific antibodies for Western blotting.

Anti-IgG, Light Chain Specific antibodies react strongly with native primary antibodies used for detecting specific protein bands on Western blots. Anti-light chain specific antibodies, however, do not bind to the reduced and denatured IgG heavy chain band (50 kD) on blots (Figures A, C, and D). Therefore, by using our new anti-light chain specific antibodies, detection of antigens with molecular weights near 50 kD is not obscured by large amounts of reduced and denatured IgG heavy chains from primary antibodies used for immunoprecipitation (IP)
(for contrast, see Figure B).

Although the new antibodies react strongly with native IgG light chains, they do not react as strongly with the reduced and denatured light chains on blots. Therefore, they are not recommended for sensitive or quantitative detection of reduced and denatured light chains on Western blots.

The antibodies have been thoroughly adsorbed to minimize cross-reactivity with immunoglobulins from many other species, which also may be present on blots.

If the protein of interest has a reduced and denatured molecular weight near 25 kD, anti-IgG, Fc fragment specific antibodies may be used to detect native IgG primary antibodies without binding to the 25 kD band of reduced and denatured IgG light chains on Western blots.