Compostions, kits and methods are provided for generating highly diverse libraries of proteins such as antibodies via homologous recombination in vivo, and screening these libraries against protein, peptide and nucleic acid targets using a two-hybrid method in yeast. The method for screening a library of tester proteins against a target protein or peptide comprises: expressing a library of tester proteins in yeast cells, each tester protein being a fusion protein comprised of a first polypeptide...

Methods are provided for generating highly diverse libraries of expression vectors encoding fusion proteins such as single-chain antibodies via homologous recombination in yeast. The method comprises: transforming into yeast cells a linearized yeast expression vector having a 5'- and 3'-terminus sequence at the site of linearization and a library of insert nucleotide sequences that are linear and double-stranded; and having homologous recombination occur between the vector and the insert sequenc...

A highly diverse library of yeast expression vectors encoding a library of fusion proteins such as antibodies is provided. The yeast expression vector formed in the library comprises: a first nucleotide sequence encoding a first polypeptide subunit; a second nucleotide sequence encoding a second polypeptide subunit; and a linker sequence encoding a linker peptide that links the first nucleotide sequence and the second nucleotide sequence. The first polypeptide subunit, the second polypeptide sub...

Methods and compositions are provided for transferring DNA sequence information from a first vector to a second vector. In the subject methods, a first vector comprising a region of DNA having a sequence of interest is contacted with a set of three pairs of oligonucleotide primers under conditions sufficient to produce three different PCR products, where each product corresponds to a different reading frame. The oligonucleotide primers comprise a first region of sequence identity with the first ...

Compositions are provided that comprise antibody against coreceptors for human immunodeficiency virus such as CCR5 and CXCR4. In particular, monoclonal human antibodies against human CCR5 are provided that bind to CCR5 with high affinity and are capable of inhibiting HIV infection at low concentrations. The antibodies can be used as prophylactics or therapeutics to prevent and treat HIV infection, for screening drugs, and for diagnosing diseases or conditions associated with interactions with HI...

Compositions are provided that comprise antibody against membrane proteins such as chemokine receptors. In particular, monoclonal human antibodies against human CXCR4 are provided that are capable of inhibiting HIV infection and chemotaxis in human breast cancer cells. The antibodies can be used as prophylactics or therapeutics to prevent and treat HIV infection and cancer, for screening drugs, and for diagnosing diseases or conditions associated with interactions with chemokine receptors.

Compositions, methods, and kits are provided for efficiently generating and screening a library of highly diverse protein complexes for their ability to bind to other proteins or oligonucleotide sequences. In one aspect of the invention, a library of expression vectors is provided for expressing the library of protein complexes. The library comprises a first nucleotide sequence encoding a first polypeptide subunit; and a second nucleotide sequence encoding a second polypeptide subunit. The first...