Abstract: Compositions are disclosed, comprising dendrimers to which a first polypeptide is controllably coupled. Such polypeptide-dendrimer compositions are effective for controllably coupling a second polypeptide to the dendrimer. The first and second polypeptides have separate and distinct defined biological activities, for example, two antibodies with first and second binding specificities or an antibody and an enzymatic label. Such compositions are useful as indicators in specific binding assays, e.g., immunoassays. Methods for sequentially coupling two different polypeptides to a dendrimer to form compositions of the invention also are disclosed.

Abstract: Methods are provided for conducting specific binding assays to determine the concentration or presence of at least one analyte in a sample. Dendrimer-reagent preparations with particular analyte specificities are mixed in solution with a sample to form dendrimer-reagent-sample complexes. The complexes are then immobilized on a solid phase. Immobilization is facilitated by coupling specific binding assay reagents such as polypeptide receptors or analytes with water soluble polymers. Such water soluble polymers, for example star polymers such as dendrimers, provide production advantages of lot-to-lot uniformity and homogeneity, and can enhance sensitivity due to low non-specific binding to the solid phase.

Abstract: Chimeric proteins containing sequences from MCP and DAF and further containing peptide sequences capable of binding glycosaminoglycans. Nucleotide sequences encoding the chimeric proteins, expression vectors containing the nucleotide sequences, as well as transformed host cells capable of producing the chimeric proteins are claimed.

Abstract: Methods and compositions are provided for specific binding assays in which specific binding reagents are immobilized on a solid phase. Immobilization is facilitated by covalently coupling specific binding assay reagents such as polypeptide receptors or analytes with water soluble polymers. Such water soluble polymers, for example star polymers such as dendrimers, provide production advantages of lot-to-lot uniformity and homogeneity, and can enhance sensitivity due to low non-specific binding to the solid phase.

Abstract: Disclosed are methods that achieve i) site-directed delivery, ii) in situ amplification, and iii) sustained expression of an exogenous gene product within renal glomeruli. An exogenous gene, E. coli .beta.-galactosidase, was introduced into cultured rat mesangial cells using a replication-defective retrovirus, and stable infectants were administered to a rat kidney via the renal artery. In the injected kidney, the engineered, cultured mesangial cells populated 40% of glomeruli site-specifically. The gene product was detected throughout a 14-week period of observation. In an alternative method, engineered, cultured mesangial cells were injected into a kidney subjected to an antibody that induces mesangiolysis followed by mesangial regeneration. Under these conditions, expression of .beta.-galactosidase was dramatically amplified in situ and high level expression continued for at least 8 weeks.