Inactivated poliovaccine

1. An attenuated recombinant poliovirus having:

(i) a 5′ non-coding region consisting of the 5′ non-coding region of Sabin 3 strain of poliovirus, modified so that it does not have a base pair mismatch in stem (a) or (b) of domain V, wherein seven or eight of the base pairs in stems (a) and (b) are U-A or A-U base pairs, and wherein:

(a) a U-A base pair is present:

(I) in stem (a) with nucleotide pairs U471 and A538 and U472 and A537; and

(II) in stem (b) with nucleotide pairs U478 and A533, U480 and A531, and U481 and A530; and

(b) an A-U base pair is present:

(I) in stem (b) with nucleotide pairs A479 and U532 and A482 and U529;

or

(c) a U-A base pair is present:

(I) in stem (a) with nucleotide pairs U471 and A538 and U472 and A537; and

(II) in stem (b) with nucleotide pairs U478 and A533, U480 and A531, and U481 and A530; and

(d) an A-U base pair is present in stem (b) with nucleotide pairs A477 and U534, A479 and U532, and A482 and U529;

(ii) a protease 2A coding region from Sabin 3; and

(iii) an entire capsid protein coding region P1 from the Sabin 1, Mahoney, MEF, or Saukett strain of poliovirus.

2. The poliovirus according to claim 1 , further having a 3′ non-coding region derived from Sabin 3.

3. The poliovirus according to claim 1 , further comprising a mutation in the protease 2A gene, said mutation being associated with higher yields of immunogenic particles in cells of monkey origin.

4. A method for producing the poliovirus according to claim 3 , comprising:

(i) passaging the poliovirus according to claim 1 in Vero cells to identify viral isolates with higher yields of immunogenic particles;

(ii) sequencing the protease 2A gene of the isolates from step (i);

(iii) identifying the poliovirus with appropriate mutations in the protease 2A gene from the isolates identified in step (ii); or

(iv) screening the poliovirus from step (i) to identify viral isolates with an unaltered degree of attenuation and a reduced temperature sensitivity as compared with poliovirus according to claim 1 that have not been passaged.

5. The poliovirus according to claim 3 , wherein the mutation in protease A does not change residues H20, D38, or C109.

6. The poliovirus according to claim 3 , wherein the mutation is any one or more of the following amino acid changes: A8V, Y10C, C17Y, N18S, T19C, Y19H, T23I, E25G, A30P, I33V, W35R, K45E, G48D, E65K, E65V, Y70C, T79A, F80L, Y82H, Y93H, H96Y, S105T, P106S, I122V, V123A, G127R, V131A, or S134T.

7. The poliovirus according to claim 1 , wherein the poliovirus is inactivated.

8. An immunogenic composition comprising the poliovirus of claim 7 .

9. The immunogenic composition of claim 8 , further comprising a pharmaceutically acceptable carrier or diluent.

10. A poliovirus according to claim 1 , wherein the poliovirus is selected as an inactivated polio vaccine (IPV) seed stock.

11. A method for preparing an inactivated polio immunogenic composition, comprising: (i) growing a poliovirus according to claim 1 in cell culture ex vivo; (ii) inactivating said poliovirus; and (iii) formulating said inactivated poliovirus with a pharmaceutically acceptable carrier or diluent.

12. The method according to claim 11 , wherein the poliovirus is grown in non-human cells.

13. A method of inducing an immune response in a subject against poliovirus, the method comprising administering to the subject the poliovirus composition of claim 9 .