Recombinant CDHR3 protein fragments inhibit rhinovirus C binding and replication

1. A soluble truncated CDHR3 peptide consisting of:

(a) SEQ ID NO:2,

(b) SEQ ID NO:31, wherein X of SEQ ID NO: 31 is selected from the group consisting of A, G, V, L, I, S, and T and wherein X correlates to residue W76 of full-length CDHR3 (SEQ ID NO: 1),

(c) a polypeptide having at least 90% identity to SEQ ID NO: 2,

(d) a polypeptide having at least 90% identity to SEQ ID NO: 31, wherein X of SEQ ID NO: 31 is selected from the group consisting of A, G, V, L, I, S, and T, or

(e) any one of the polypeptides of (a)-(d) further comprising a linker peptide of SEQ ID NO: 15, SEQ ID NO: 16 or both.

2. The soluble truncated CDHR3 peptide of claim 1 ,

wherein the peptide further comprises at least one linker, wherein the at least one linker is SEQ ID NO:15 attached to the N-terminus of the CDHR3 peptide, SEQ ID NO:16 attached to the C-terminus of the CDHR3 peptide, or both.

3. The soluble truncated CDHR3 peptide of claim 1 , wherein the soluble truncated CDHR3 peptide further comprises amino acids encoding a heterologous tag.

4. The soluble truncated CDHR3 peptide of claim 1 , wherein X is alanine.

5. The soluble truncated CDHR3 peptide of claim 1 , wherein the soluble truncated CDHR3 peptide is covalently or non-covalently linked to a heterologous tag.

6. The soluble truncated CDHR3 peptide of claim 5 , wherein the tag is a FLAG tag or a HIS tag.

7. A therapeutic composition for reducing or preventing rhinovirus C entry into cells, the composition comprising any one of the soluble truncated CDHR3 peptides of claim 1 and Ca++ in a pharmaceutically acceptable carrier.

8. A vector comprising the nucleic acids encoding the soluble truncated CDHR3 peptide of claim 1 .

9. A cell comprising the vector of claim 8 .

10. The cell of claim 9 , wherein the cell is a bacterial cell.

11. A method of making the soluble truncated recombinant peptide of CDHR3, the method comprising:

(a) transforming bacterial cells with the vector of claim 8 ;

(b) inducing recombinant protein expression in the bacterial cells;

(c) lysing bacterial cells and collecting by centrifugation the inclusion bodies comprising the soluble truncated peptide;

(d) solubilizing the protein within the inclusion body; and

(e) dialyzing and refolding the protein in buffer supplemented with Ca++ to produce soluble truncated recombinant peptides of CDHR3.

12. The method of claim 11 , wherein the buffer of (e) is a pharmaceutically acceptable buffer supplemented with about 1-10 mM CaCl 2 .

13. A method for reducing the infection by human rhinovirus C (HRV-C) of a host cell susceptible to infection by HRV-C, comprising: contacting the HRV-C with the soluble truncated CDHR3 peptide of claim 1 in an amount effective to reduce the infectivity of the HRV-C.

14. The method of claim 13 , wherein the method is performed in vivo.

15. An in vitro assay for testing an agent for anti-viral activity against rhinovirus C, the assay comprising the steps of:

(a) contacting the agent with the soluble truncated CDHR3 peptide of claim 1 and rhinovirus C; and

(b) assaying the ability of the agent to disrupt binding of the soluble truncated CDHR3 peptide of claim 1 to rhinovirus C.

16. The assay of claim 15 , wherein the assay further comprises:

(c) incubating the rhinovirus C pre-incubated with the soluble truncated CDHR3 peptide of claim 1 and the agent or with the agent alone with host cells, and measuring the infectivity of the rhinovirus C in the host cell and utilizing the soluble truncated CDHR3 peptide as a positive contra.

17. The assay of claim 16 , wherein the soluble truncated CDHR3 peptide of claim 1 is attached to a solid support.

18. The assay of claim 17 , wherein the solid support is a tissue culture dish or plate.