Variation in the spike protein of the 793/B type of infectious bronchitis virus, in the field and during alternate passage in chickens and embryonated eggs

Figures & data

Figure 1. Relationships between the UK and French isolates of the 793/B serotype illustrated by a maximum likelihood phylogeny unrooted tree, based on nucleotides 1 to 561. (a) Nucleotide sequences. (b) Amino acid sequences. The French isolates are shown in bold. The oldest isolate, FR/CR85131/85, has been boxed.

Table 1. Host-dependent variation at nucleotide position 283 (encoding amino acid residue 95) of the S1 part of the S gene of UK/4/91

Nucleotide at position 283 (amino acid encoded)
Field isolate	Egg-passaged derivative	Back passage in chickens (BP/C) of UK/4e/91		Passage in embryonated eggs of BP/C10
UK/4f^a/91	UK/4e^b/91	BP/C^c1^d	BP/C10^d	BP/C10/E^e10^a
T (serine)	T (serine)^f	T (serine)^f	T (serine)
	G (alanine)^f	G (alanine)^f		G (alanine)
^a f, field strain of isolate 4/91.
^b e, egg-passage of strain 4/91.
^c C, chicken.
^d Passage number (1 or 10).
^e E, embryonated egg.
^f Sequencing revealed a mixed population comprising both T and G residues.