Immune Complex Transfer Enzyme Immunoassay for Antibodies Using Recombinant Proteins Labeled with 2,4-Dinitrophenyl Group and .BETA.-D-Galactosidase.

Abstract

Ultrasensitive enzyme immunoassays (immune complex transfer enzyme immunoassays) were developed for antibody IgGs. Antibody IgGs were reacted with 2, 4-dinitrophenyl-antigen and antigen-β-D-galactosidase conjugate, and the immune complexes comprising the three components were trapped onto solid phase coated with (anti-2, 4-dinitrophenyl group) IgG and were transferred to solid phase coated with (antihuman IgG γ-chain) IgG in the presence of eN-2, 4-dinitrophenyl-L-lysine. These immunoassays were much more sensitive and specific than currently available conventional methods and were applied for detection of antibody IgGs to HIV-1. Diagnosis and confirmation of HIV-1 infection using urine, whole saliva and serum samples became more reliable with less indeterminate results. And the window period in diagnosis of HIV-1 infection, during which diagnosis of HIV-1 infection is not possible due to the absence of detectable antibodies to HIV-1, was shortened by approximately two weeks with the immune complex transfer enzyme immunoassay for simultaneous detection of p24 antigen of HIV-1 and antibody IgGs to p17 antigen and reverse transcriptase of HIV-1 in a single assay tube. Furthermore, it has recently become possible to perform the immune complex transfer enzyme immunoassay within 2 to 3 hr with higher sensitivity and, as a result, to further shorten the window period in diagnosis of HIV-1 infection.