Bovine serum albumin antigenic structure

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. 

Structural and antigenic properties of proteins are expected to change after one-electron redox processes whatever they are. Such effect was demonstrated using ovalbumin and bovine serum albumin (226). Antigenicity was decreased by irradiation. This change could be related to that measured by circulary dichroism at 222 nm. The authors suggest that the main part of conformation-dependent antigenic structure is lost by irradiation. 

To act as immunogens, PGs are covalently linked to an antigenic carrier. The chemical action selected must enable an adequate number of molecules to be bound to the carrier, and maintain the structural integrity of the molecule (except for the group involved in the covalent bond with the antigenic carrier). In our experiments, we used bovine serum albumin (BSA) as the carrier the free carboxyl function of the hapten, activated by a carbodi-imide, forms a peptide bond with the free NH2 groups of the antigenic carrier (8). Under our conditions (shov/n... 

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