Immune complex transfer enzyme immunoassay for (anti-human T-cell leukemia virus type I) IgG in serum using a synthetic peptide, Env gp46(188-209), as antigen

An immune complex transfer enzyme immunoassay for (anti-human T-cell leukemia virus type I) IgG (anti-HTLV-I IgG) in serum using a chemically and safely synthesized peptide, env gp46(188-209), is described. Anti-HTLV-I IgG in test serum, which had been incubated with excess of inactive beta-D-galactosidase to eliminate interference by anti-beta-D-galactosidase antibodies, was reacted simultaneously with dinitrophenyl bovine serum albumin-env gp46(188-209) conjugate and env gp46(188-209)-beta-D-galactosidase conjugate. The complex formed of the three components was trapped onto polystyrene balls coated with affinity-purified (anti-dinitrophenyl group) IgG. After washing to eliminate nonspecific IgG in the test serum and excess of the beta-D-galactosidase conjugate, the complex was eluted from the polystyrene balls with dinitrophenyl-L-lysine and transferred to polystyrene balls coated with affinity-purified (anti-human IgG gamma-chain) IgG. beta-D-Galactosidase activity bound to the (anti-human IgG gamma-chain) IgG-coated polystyrene balls was assayed by fluorometry. This assay was sensitive and detected anti-HTLV-I IgG in serum samples which were negative by the conventional enzyme immunoassay and Western blotting. And the specificity of this assay was confirmed by preincubation of test serum with excess of env gp46(188-209). However, some disadvantages were also noted.