Method for determining the equilibrium constant and the concentration of influenza virus IgG antihaemagglutinin antibody molecules by use of EIA titres determined with and without guanidine hydrochloride.
A novel technique for determining the concentration of influenza virus antihaemagglutinin antibody molecules (A) of the IgG class and their equilibrium constant (K) is described which is based on recording EIA (enzyme-linked immunosorbent assay) guanidine titre ratios R (EIA titre determined in the absence of guanidine divided by EIA titre determined in the presence of 0.25 M guanidine hydrochloride). K is determined by using a regression line relating values of K to values of R. The line was established by testing antisera comparatively for K by means of equilibrium filtration and for R by EIA. The assay of A is based on the finding that the concentration of antibody molecules adsorbed at serum dilutions yielding an O.D. reading of 0.9 in the EIA test is within the experimental limits constant. Since K is known, this point of reference can be used to calculate A. For a panel of 57 influenza antisera, the A and K values determined by equilibrium filtration agreed well with the respective values determined by use of the novel technique.
Drescher
J
J
Institute of Virology, Hannover Medical School, Germany.
Verhagen
W
W
D000818:Animals; D000914:Antibodies, Viral / Q000032:analysis* / Q000737:chemistry; D000915:Antibody Affinity; D002645:Chickens; D019791:Guanidine; D006146:Guanidines; D007118:Immunoassay; D009980:Influenza A virus / Q000276:immunology*; D008433:Mathematics
D000914:Antibodies, Viral; D006146:Guanidines; D019791:Guanidine