Human serum albumin, antigenic

Antigens (e.g., bovine or human serum albumin, bovine gamma globulin, ovalbumin, penicillin)... 

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]. 

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.

Table 1.10. Some pharmaceutical substances originally isolated from animal sources. While some are still produced by direct extraction from the native source, others are now also produced by direct chemical synthesis (e.g. peptides and some steroids), or by recombinant DNA technology (most of the pol5 peptide products). Abbreviations hGH = human growth hormone FSH=follicle stimulating hormone hCG=human chorionic gonadotrophin HSA=human serum albumin HBsAg=hepatitis B surface antigen...

Dolovich J, Evans SL, Nieboer E. 1984. Occupational asthma from nickel sensitivity I. Human serum albumin in the antigenic determinant. Br J Ind Med 41 51-55. 

Instead of using human serum albumin as a carrier protein, other workers (135) utilized ovalbumin for preparing the diazotized clenbuterol antigen in an enzyme immunoassay developed for screening of clenbuterol residues in bovine urine, liver, and eye. Alkaline phosphatase rather than -galactosidase was also used as an enzyme label in the preparation of the enzyme-clenbuterol conjugate. 

In order to determine if lectins affect the reactions of complement mediated hemolysis subsequent to binding of antibody to the lymphocyte we have employed a synthetic particulate antigen. This was accomplished by testing the ability of lectin to inhibit the fixation of complement by the complex of anti-human serum albumin (HSA) and HSA-conjugated aminoethyl Biogel beads. The HSA-conjugated aminoethyl Biogel beads may be considered to be cell-like particles coated with a carbohydrate-free protein. 

One can be relatively certain that a protein will be immunogenic if it has a molecular weight >10,000 and if it is immunochemi-cally foreign to the animal receiving the antigen. One should also consider the ultimate use of the antibody when choosing the carrier protein. For instance, human serum albumin would be a poor carrier for a hapten if the resulting antibody were to be used to monitor human blood samples by immunodiffusion. 

Antibodies to one protein antigen will often react (cross-react) with a wide variety of similar proteins from other species. For example, 15% of the antibody in a polyclonal antiserum to bovine serum albumin will react with human serum albumin. The molecular basis for this cross-reaction is not clearly understood, but cross-reactivity is believed to be caused by the presence of a configuration of amino acid side chains on another protein molecule that has a sufficient overall similarity to the specific configuration on the original antigen that induced antibody formation. 

An enzyme immunoelectrode suitable for the assay of human serum albumin and insulin uses an oxygen electrode covered with an antibody-containing nylon net kept in place with an O-ring. From 1 to 25 ng/L of albumin and 5 to 100 ng/L of insulin can be assayed (306). A specific sensor for the tumor antigen a-fetoprotein (AFP) is prepared by immobilizing anti-AFP antibody covalendy on a membrane prepared from cellulose triacetate, 1,8-diamino-4-aminomethyl octane, and GA (307). The sensor is applied to an EIA based on competitive Ab/... 

Fig. 7. Cross-reaction of anti-human serum albumin rabbit serum (IS) with the homologous antigen (human serum albumin in solution S2), and with a heterologous antigen (horse serum albumin in solution SI) in three of the techniques illustrated in Pig. 1 (A) simple diffusion in one dimension in a ceil with parallel walls (photographed after 2 hr) (B) double diffusion in one dimension in a cell with parallel walls (photographed after 2 days). In A and B the interfaces between the different layers are indicated by white dashes. (C) Double diffusion in two dimensions in a plate with square reservoirs (photographed after 3 days). For further explanations see text. From J. Oudin. ...

Fig. 11. Electrophoretic distribution in agar of gastric mucosal extract protein (A) protease activity at pH 2.2 (B) carboxylic esterase activity (C) and immuno-electrophoretic pattern (D). The relative mobility is shown at the bottom (UR) with 0 representing the location of the uncharged dextran, levan and 1 the migration of human serum albumin. The zones of mobility (Z), arbitrarily defined on the basis of protein distribution, are indicated at the top. Each antigen and enzyme is designated by the zone in which it is found. The antigens are alsc designated by a letter. From Kushner et al. (K32).

One of the earliest efforts of qualitative measurement of a protein (human serum albumin) in a microchip-based device was based on bead agglutination in a microchamber (approximately lOjaL). Subsequently, several quantitative immunoassays have been performed using microchip electrophoretic systems that permit separation and quantitation of free- and bound-labeled antigens in competitive assays (see Chapter 5). Most are carried out in channels micro-machined into fused silica substrates. Early work on quantitative assays achieved measurement of cortisol in serum.The assay used cortisol labeled with fluorescein and an argon laser detector at 488 nm and required only 80 pL of a 40x dilution of serum as the sample. Other capillary electrophoresis-based assays for a variety of antibodies have also been developed that include immunoglobulins (IgG, IgA, and IgM), antibovine serum albumin, and antiestradiol. ... 

L2. Lapresle, C., Kaminski, M., and Tanner, C. E., Immunochemical study of the en-Z3unatic degradation of human serum albumin. An analysis of the antigenic structure of a protein molecule. J. Immunol. 82, 94-102 (1959). 

W13. Webb, T., and Lapresle, C., Isolation and study of rabbit antibodies specific for certain of the antigenic groups of human serum albumin. Biochem. J. 91, 24r-31 (1964). 

In homogeneous competitive assays the electrode-active group of the labeled antigen is masked by the bound antibody. Such electrochemical immunoassays have been developed for human serum albumin (HSA) (Alam and Christian, 1982,1985). HSA was labeled with Pd2+ or Zn2+, and the bound metal ion was measured by differential pulse polarogra-phy at a mercury electrode. Binding of antibody caused a drop of the peak current. 

The antigens induce not only an immune response but equally react with the antibodies, which are caused to appear by the living organism. However, these two properties are different. Small organic molecules such as pesticides are not able of inducing a production of antibodies. In the other hand, the antigens will react if an adapted antibody is already present these small molecules are called the haptens. To generate the antibodies characteristic to a hapten, the latter must be attached by a covalent bond to transporter proteins (BSA or HSA bovine or human serum albumin), or to a polysaccharide. Therefore, the hapten must have reactive functionality and this structural modification must not influence the specificity of the antibodies that will be produced. 

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