Proteins immunological comparisons

Fig. 1. Confidence limits and prediction intervals for immunological comparisons of five proteins. For each protein the heavy central line is the regression line through the origin relating immunological distance in the microcomplement fixation test to percent difference in amino acid sequence, and the shaded region portrays the 95% confidence limits for that line. The outer two lines in each graph define the boundaries of the intervals for one prediction made at the 90% level of confidence.

L3. Laterre, E. C., Heremans, J. F., and Carbonara, A., Immunological comparison of some proteins found in cerebrospinal fluid, urine and extracts from brain and kidney. Clin. Chim. Acta 10, 197-209 (1964). 

Shek, P.N., and Sabiston, B.H. (1982b) Immune response mediated by liposome-associated protein antigens. II. Comparison of the effectiveness of vesicle-entrapped and surface-associated antigens in immu-nopotentiation. Immunology 47, 627. 

The co-identity of different proteins can be confirmed only by comparisons of amino acid sequences or by immunological cross-reactions. That cold-regulated polypeptides have a role in the acquisition of cold tolerance is supported by the general observation that the appearance of most proteins is temporally correlated with the onset of freezing tolerance. The polypeptides are detected as long as the plants are kept at low temperatures but decline when the temperature is raised as, for example, demonstrated by Guy Haskell (1987, 1988) for spinach. Similar associations of appearance and decline of polypeptides have been reported for alfalfa (Mohapatra et al., 1987a,b). 

In addition to comparison of amino acid and nucleotide sequences of a-lactalbumin, and their rates of change as molecular clocks, a considerable amount of comparative information has accumulated on the three-dimensional structure of these proteins their physical properties in soludon effects of amino acid subsdtudons, in both genetic and cloned variants and their funcdons and immunological properties. In assessing this informadon it is important not to lose sight of the known paleontological informadon on the origin and evolution of mammals. 

In the absence of reliable predictive methods for assessing potential immunological cross-reactivity, a comparative sequence analysis approach can be used to identify whether or not known epitopes from human proteins exist in a candidate vaccine antigen. The Immune Epitope Database (IEDB) provides a comprehensive reference data set for known epitopes.78 When screening potential vaccine candidates, the presence of known human-derived epitopes can be ruled out by comparison against the IEDB (www.iedb.org). 

Validation experiments are carried out by fortification of samples with the analyte in question and comparison with independent control methods such as GC, GC/MS or LC. Samples from a number of individuals should be used in any validation experiment because of the inherent variability of biological matrices. Features such as pH, protein, sugar and salt concentration must be considered. Also the intake of drugs can interfere with the immunological determination of environmental pollutants. 

The staphylococcal enterotoxins are moderately stable proteins therefore, immunological evaluation should be possible on samples collected in either deployed or fixed medical treatment facilities. Immunoassays can detect picogram quantities of toxins in environmental samples. For comparison, 440 pg/mL was reported as the mean concentration of TSST-1 in human sera from patients with toxic shock syndrome.25 Anti-TSST-1 antibody titers are either suppressed or depleted in patients with toxic shock syndrome26,27 and the levels only recover during convalescence. In addition, most normal human serum samples contain detectable levels of antibody reacting with several different bacterial pyrogenic toxins, including... 

Brennand DM, Danson MJ, and Hough DW (1986) A comparison of ELISA screening methods for the production of monoclonal antibodies against soluble protein antigens. Journal of Immunological Methods 93 9-14. 

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