Surface plasmon resonance immunosensor for IgE analysis using two types of anti-IgE antibodies with different active recognition sites.
A simple and novel method for the determination of an IgE antibody based on a surface plasmon resonance immunosensor for the diagnosis of an allergy is described. The method involves the use of an anti-IgE(D) antibody and an anti-IgE(H) antibody, which reacts with the Ce2 domain and the Ce3 domain of the IgE antibody. The anti-IgE(D) antibody was immobilized on the gold surface of a sensor chip by physical adsorption. An IgE antibody sample was incubated by adding it to an anti-IgE(H) antibody solution to form an anti-IgE(H) immunocomplex through a reaction of the Ce3 domain of the IgE antibody. The incubated solution was introduced onto the sensor chip and the immunocomplex of the IgE-anti-IgE(H) then reacted with the anti-IgE(D) antibody immobilized on the sensor chip through the Ce2 domain of the IgE antibody part of the IgE-anti-IgE(H) immunocomplex. The detection limit of the present method for the determination of the IgE antibody was about 10 ppb. The affinity constants for the anti-IgE(H) antibody immunocomplex with the IgE antibody in solution and that of the anti-IgE(H) antibody immunocomplex with the IgE antibody immobilized on the sensor chip by a biotin-streptavidin interaction were estimated to be 4.1 x 10(7) M(-1) and 5.8 x 10(6) M(-1), respectively. The affinity constant for the immunocomplex of the anti-IgE(H) antibody with the IgE antibody with the anti-IgE(D) immobilized on the sensor chip was estimated to be 4.9 x 10(7) M(-1), 20-times larger than the affinity constant for the IgE antibody immunocomplex with the anti-IgE(D) antibody immobilized on the sensor chip, based on a direct immunoassay method of the IgE antibody under the same experimental conditions.
Li
Yan
Y
Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, Fukuoka, Japan.
Ren
Jujie
J
Nakajima
Hizuru
H
Soh
Nobuaki
N
Nakano
Koji
K
Imato
Toshihiko
T
D000465:Algorithms; D000906:Antibodies / Q000032:analysis*; D000936:Antigen-Antibody Complex / Q000737:chemistry; D015374:Biosensing Techniques; D002138:Calibration; D004797:Enzyme-Linked Immunosorbent Assay; D006046:Gold; D007118:Immunoassay / Q000379:methods*; D007073:Immunoglobulin E / Q000032:analysis*; D008970:Molecular Weight; D011946:Receptors, Antigen / Q000032:analysis*; D020349:Surface Plasmon Resonance / Q000295:instrumentation*
D000906:Antibodies; D000936:Antigen-Antibody Complex; D011946:Receptors, Antigen; D007073:Immunoglobulin E; D006046:Gold