Abstract: Novel polypeptides are provided having substantially the same sequence as immunologically significant fragments of AIDS-related viruses. The polypeptides can be used as reagents in the determination of exposure of a human host to the virus. Of particular interest is the use of polypeptides in screening blood products.

Abstract: Peptides immunoreactive with antibodies to native proteins, and which have at least two cysteine residues that contribute to mimicking an epitope of the protein, are prepared with the cysteine thiol groups protected. When deprotected, the peptides have enhanced immunoreactivity.

Abstract: Peptides immunoreactive with antibodies to native proteins, and which have at least two cysteine residues that contribute to mimicking an epitope of the protein, are prepared with the cysteine thiol groups protected. When deprotected, the peptides have enhanced immunoreactivity. The peptides are particularly useful for detecting antibodies or antigens associated with retroviruses, including the clinically important lymphotropic retroviruses HIV-1, HIV-2, HTLV-I, and HTLV-II.

Abstract: Rapid assays for analytes of interest in a fluid sample utilize a first conjugate of a labelled reactant that specifically binds to the analyte, and a second conjugate that binds to the analyte coupled to a polymer that has an affinity for a selected solid phase. The reaction components are incubated briefly, then contacted with the selected solid phase and the labelled components determined. Optional wash steps provide for enhanced sensitivity and specificity. When the analyte of interest is an antibody to HIV, the first reactant may be a synthetic, recombinant or native HIV antigen, and the second reactant may be protein A or an anti-immunoglobulin.

Abstract: Methods for determining the presence and/or concentration of an analyte in a biological fluid sample are disclosed. The methods generally include admixing in solution certain polymer/reactant and reporter/reactant conjugates along with the biological fluid sample suspected of containing the analyte, thereby forming ternary complexes. The separation of the complexes from the reaction mixture is achieved through the affinity of certain selected polymer compositions for various solid phases. Upon separation, the amount of reporter activity in the solution may be measured, and therefrom the presence and/or concentration of the analyte determined. Multiple analyses on a biological fluid sample suspected of containing one or more analytes may also be performed, using either a variety of different reporters or selected polymers having varied affinity for the solid phase.