The Pirbright Institute

Paul Britton

Erica Bickerton

Sarah Keep

Maria Armesto

The present invention provides a live, attenuated coronavirus comprising a mutation in non-structural protein nsp-3 and/or deletion of accessory proteins 3a and 3b. The coronavirus may be used as a vaccine for treating and/or preventing a disease, such as infectious bronchitis, in a subject.

Attenuated infectious bronchitis virus

The present invention provides a live, attenuated coronavirus comprising a variant replicase gene encoding polyproteins comprising a mutation in one or more of non-structural protein(s) (nsp)-10, nsp-14, nsp-15 or nsp-16. The coronavirus may be used as a vaccine for treating and/or preventing a disease, such as infectious bronchitis, in a subject.

Coronavirus

The present invention provides an infectious bronchitis virus (IBV) spike protein (S protein) which is based on an S protein from an IBV strain with restricted tissue tropism, but which comprises the sequence XBBXBX in the part of the S2 protein corresponding to residues 686 to 691 of the sequence given as SEQ ID No. 2, where B is a basic residue and X is any amino acid; and which comprises at least one of the following amino acid substitutions with reference to the position numbering of SEQ ID NO:2: Leucine (L) to Phenylalanine (F) at position 578 Asparagine (N) to Serine (S) at position 617 Asparagine (N) to Serine (S) at position 826 Leucine (L) to Phenylalanine (F) at position 857 and Isoleucine (I) to Valine (V) at position 1000 such that an IBV virus comprising the S protein has extended tissue tropism. The present invention also provides a virus comprising such an S protein.

Mutant spike protein extending the tissue tropism of infectious bronchitis virus (IBV)

The present invention provides a chimaeric coronavirus S protein which is based on an S protein from a coronavirus strain with restricted tissue tropism, but which comprises at least part of the S2 subunit from a coronavirus strain with extended tissue tropism, such that a virus comprising the chimaeric S protein has extended tissue tropism. The present invention also provides a virus comprising such a chimaeric S protein.

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Woking, United Kingdom

Paul Britton