Surface expression libraries of heteromeric receptors

A method of constructing a diverse population of vectors capable of expressing diverse populations of first and second polypeptides which form a diverse population of heteromeric receptors of the immunoglobulin superfamily, comprising:

• (a) operationally linking to a first vector a first population of diverse DNA sequences within a first gene family encoding a diverse population of first polypeptides of the heteromeric receptor of the immunoglobulin superfamily, said first vector having two pairs of restriction sites symmetrically oriented about a cloning site;
• (b) operationally linking to a second vector a second population of diverse DNA sequences within a second gene family encoding a diverse population of second polypeptides of the heteromeric receptor of the immunogobulin superfamily, said second vector having two pairs of restriction sites symmetrically oriented about a cloning site in an identical orientation to that of the first vector, wherein polypeptides encoded by said first and second gene families are known to form heteromeric receptors of the immunoglobulin superfamily;
• and
• (c) combining vector sequences produced by step (a) and step (b) under conditions which allow only the operational combination of said vector sequences containing said first and second populations of diverse DNA sequences.