| abstract |
A method is provided for preparing immunoassay reagents involving labeled members of specific binding pairs substantially enriched relative to contaminating labeled materials. The method involves conjugating a member of a specific binding pair to a support by a covalent bond which is cleavable under mild conditions to provide a binding pair member-support conjugate. Combining the binding pair member-support conjugate with a labeled composition containing the reciprocal member of the binding pair, so that the labeled reciprocal member becomes bound to the support through the binding of the specific binding pair. Separating the support to which is bound the labeled member from the remaining labeled material and then cleaving the bond joining the labeled specific binding pair to the support to provide labeled reagent for immunoassays. In particular, an antibody is linked to a support by disulfide linkage and a composition containing the reciprocal antigen to the antibody is labeled with a chromophore, particularly fluorescer. The support is freed of labeled material other than the desired labeled antigen and the disulfide link cleaved to provide labeled reagent for immunoassays. |