Antigenic sites of serum albumin

Also, the antigenic sites of the a-chain of Hb (6), and the six major antigenic sites of serum albumin (8-11) (FTg. 7) will be given. 

It is hoped that the three-dimensional structure of albumin or at least of an immunochemicaily reactive fragment will be available for the final delineation of the antigenic sites of serum albumin. 

The nature of the antigenic determinant has been characterized in a male worker with occupational asthma from nickel [415, 416] the antibody recognized Ni2+ bound at the natural Cu2 + /Ni2+ transport site of human albumin. The interpretation was deduced from metal ion blocking experiments and from the good agreement obtained between the pH dependency of the formation of the Ni2 + -albumin complex and the antigen-antibody complex. It was suggested that the antibody interaction depended on a special structural feature of the interaction of Ni2 + with human serum albumin, and perhaps the ability to form an octahedral complex affords one explanation [417]. 

This article focuses mainly on the Immunology of proteins whose complete antigenic structures have been chemically localized and synthetically confirmed. These are Mb, lysozyme, Hb and serum albumin. The antigenic sites of many other proteins are now being Investigated. 

Volume 3 is devoted primarily to the antibody aspect of the immune recognition and the immunochemistry of the complement system. The structure of antibodies is discussed and correlated with our present knowledge of antibody effector sites, antigenic features, and combining sites. This is followed by a chapter on the immunochemistry and biology of complement proteins and finally by a review of our current knowledge of the immunochemistry of serum albumin. 

Figure 7. Structure and location of the six regions of bovine serum albumin (BSA) and of human serum albumin (HSA) that we have shown to carry antigenic sites. It Is not Implied that the antigenic sites comprise the entire size of the regions shown, but rather that they fall within these regions. Reproduced with permission from Refs. 9, 10, and 11.

Antigens not only induce an immune response, but will also react with antibodies existing in a living organism. These two properties are different. Small molecules like pesticides are not able to induce the production of antibodies. They can only react with antibodies already present. They are called haptens. To generate antibodies specific to a hapten, haptens must be covalently bonded to a protein (e.g. BSA Bovine Serum Albumin) or polysaccharide. Therefore, the hapten must have reactive sites. On the other hand, this modification in the structure must not influence the specificity of the antibodies that will be produced. 

Apply a specific antigen (Ag) solution to a microtitre plate capable of adsorbing antigens by nonspecific hydrophobic interaction. Add a non-interfering protein such as bovine serum albumin (BSA) to occupy any remaining attachment site on the plate. 

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