In the first experiment at Pirbright, 3 immunised pigs and 4 non-immune pigs were challenged with Benin 97/1. In the second experiment at Ploufragan, a total of 12 pigs were immunised and challenged with either Benin 97/1 or virulent Uganda 1965. Ten pigs were prepared as non-immune controls and challenged with either Benin 97/1 or virulent Uganda 1965. As a control for weight gain, an extra group of 5 pigs were included in this experiment. In the third experiment at Ploufragan, a group of 7 pigs were inoculated and 6 of these and 6 non-immunised pigs were challenged with Benin 97/1. All 9 immune pigs Bosutinib in vivo from experiments 1 and 3 were protected from challenge with
the Benin 97/1 without any clinical signs of ASF (Fig. 1 and Fig. 2). In experiment 2, the 4 immune pigs challenged with the virulent Uganda 1965 isolate were all protected, although 2 of these pigs showed very short transient pyrexia. However, 2 pigs (1811, 1844) from experiment 2 were not protected following challenge with Benin 97/1 (Fig. 1 and Fig. 3). Thus the survival rate of immune pigs challenged with either Benin 97/1 or Uganda 1965 virulent isolates was 100% in two experiments (Fig. selleck products 1 and Fig. 3) and 60% following challenge with Benin 97/1 in experiment 2. In experiment 1, no adverse effects or clinical signs were observed
following the immunisation, the boost or challenge. In one pig (VR89) low copy numbers of virus genome were detected in blood by qPCR, but not by HAD assay, at 14 days post-boost with OURT88/1 (data not shown). ASFV was not detected in any tissues collected from immune pigs at the termination of the experiment. In contrast, all the non-immune pigs challenged with Benin 97/1, developed typical ASF Liothyronine Sodium symptoms including high viraemia (∼107 copies of the virus genome/ml; and up to 8.8 HAD50/ml virus), and died or were euthanized for ethical reasons within 7 days of challenge (Fig. 2A and B).
Post-mortem examination and detection of ASFV from tissues collected from these animals by qPCR and HAD assay confirmed severe ASFV infection in the non-immune pigs (up to 107 HAD50/mg tissue) (see summary in Supplementary Table 2). In the second experiment of the 12 immunised pigs, 5 (pig numbers 1826, 1829, 1834, 1837 and 1845) developed a transient pyrexia (Supplementary Fig. 1) following immunisation with OURT88/3. After the OURT88/1 boost, 4 pigs (pig numbers 1809, 1819, 1822 and 1841) developed pyrexia (Supplementary Fig. 1). Viraemia was detected from pigs 1819 and 1841 by qPCR and HAD assays (4.07 × 106 genome copies/ml: 6 HAD50/ml and 6.19 × 103 genome copies/ml: 3.25 HAD50/ml respectively). Virus genome was detected at low copy numbers by qPCR in blood samples from an additional 2 pigs but these were negative by HAD assay.