The response of pigs inoculated with a thymidine kinase-negative (TK −) pseudorabies virus to challenge infection with virulent virus

• Published in: Comparative immunology, microbiology and infectious diseases microbiology and infectious diseases, 2000, Vol.23 (1), p.15-26
• Main Authors: Ferrari, M., Gualandi, G.L., Corradi, A., Monaci, C., Romanelli, M.G., Losio, M.N., Cantoni, A.M., Pratelli, A.
• Format: Article
• Language: English
• Subjects: Administration, Intranasal; Animals; Antibodies, Viral - blood; Biological and medical sciences; Deoxyribonuclease BamHI - chemistry; DNA Primers - chemistry; DNA, Viral - chemistry; Electrophoresis, Agar Gel - veterinary; Fundamental and applied biological sciences. Psychology; Herpesvirus 1, Suid - enzymology; Herpesvirus 1, Suid - immunology; Herpesvirus 1, Suid - pathogenicity; Injections, Intradermal - veterinary; Lung - pathology; Microbiology; Mutant TK; Nasal Mucosa - virology; Neutralization Tests - veterinary; Pigs; Polymerase Chain Reaction - veterinary; Porcs; Pseudo-rage virus; Pseudorabies - immunology; Pseudorabies virus; Swine; Swine Diseases - immunology; Swine Diseases - virology; Thymidine Kinase; TK − mutant; Trigeminal Ganglion - virology; Vaccination - veterinary; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies; Viral Vaccines - administration & dosage; Viral Vaccines - immunology; Virology; Virulence
• ISSN: 0147-9571; 1878-1667
• DOI: 10.1016/S0147-9571(99)00019-3

12 Large-White-Landrace piglets were subdivided in four groups of 3 and housed in separate units. The piglets of three groups were inoculated with the 86/27V 6C2 thymidine kinase negative (TK −) mutant of pseudorabies virus (PRV), by different routes. A second inoculation with the same mutant was given to the pigs 21 days later. The animals of a fourth group were left as uninoculated controls. 21 days following the second inoculation with the TK − mutant all pigs were challenge infected with the virulent PRV. On post challenge day (PCD) 30 all pigs were killed and samples for virus detection and histology were taken from several organs. The inoculated TK − mutant of PRV did not induce any ill effects in the pigs except a transient febrile reaction in some animals. Virus was recovered from nasal swabbings from one pig 2 days after the first inoculation of the mutant. After challenge exposure with virulent PRV, the TK − mutant-inoculated pigs were apparently protected, whereas the control pigs all were severely affected and recovered very slowly over 3 weeks. Virus was isolated from the nasal swabbings from the TK − mutant-inoculated pigs on PCDs 2 and 4, whereas the nasal swabbings from the control piglets were all positive for virus from PCD 2 through PCD 10. DNA analysis of the virus recovered showed a pattern identical to that of the virulent PRV. Histologic lesions were found in the respiratory and the central nervous systems, however, the lesions in the TK − mutant-inoculated pigs were much milder compared to those registered for the control pigs. Virus was not isolated from any of the tissue samples that were tested, but viral DNA with sequences typical of PRV genome was detected by PCR in all samples of trigeminal ganglia from either the TK − mutant-inoculated pigs or from the controls. Douze porcelets de race Large-White-Landrace ont été divisés en quatre groupes de trois animaux rassemblés dans des locaux différents. Un mutant négatif pour la thymidine kinase (TK −) du virus de la pseudo-rage (86/27V 6C2) a été inoculé selon différentes voies aux porcelets de trois groupes. Vingt et un jours plus tard, une deuxième inoculation a été effectuée avec le même virus mutant. Les animaux du quatrième groupe, non inoculés, ont constitué le groupe témoin. Vingt et un jours après la deuxième inoculation avec le mutant TK −, tous les porcelets ont été infectés expérimentalement avec le virus pathogène de la pseudo-rage (PRV). Trente jours après l'infection to