Studies of biological properties of continuous suspension ВНК-21/SUSP/ARRIAH cell line

The results of the studies of cytomorphological, karyological, cultural properties of continuous suspension ВНК-21/SUSP/ARRIAH subline of newborn Syrian hamster kidney cells intended for foot-and-mouth disease, rabies, bovine parainfluenza-3, Aujeszky’s disease virus reproduction, as well as for production of diagnostic veterinary biologicals are presented. When cultured in suspension, BHK-21/SUSP/ARRIAH cell subline undergoes selection towards hypoploidy: modal class is represented by cells with 41 chromosomes (32–40% of cells); the share of cells containing 40–42 chromosomes is 78–80%; the share of polyploids averages around 1%; the range of variation in the number of chromosomes is from 36 to 54. BHK-21/SUSP/ARRIAH cell subline cultured in suspension with cell seeding concentration of 0.6–0.8 million cells/cm3 demonstrates growth rate of 6.67–11.00 and 96–99% cell viability. After 48 hours, G1-phase (diploid-2n) cells prevail in the cell population of the new subline (30.0–75.0% of cells); cells that undergo preparation for mitosis (S-phase) and mitosis (G2+M-phase) account for 3.0 to 20.0% of the entire population; the number of meganucleated and multinucleated cells (>4n) at the beginning and at the end of the logarithmic phase increases to 2%. BHK-21/SUSP/ARRIAH cells recover rapidly after cryopreservation and demonstrate 95–99% viability and growth rate of 3.36–5.88 at passages 1 to 3 and 6.85–10.95 at passages 4 to 12. Continuous suspension BHK-21/SUSP/ARRIAH cell line ensures virus accumulation at the following titres: FMD virus – 7.30– 8.00 lg TCID50/cm3, rabies virus – 7.25–8.00 lg CCID50/cm3, bovine parainflunza-3 virus – at least 6.00 lg TCID50/cm3, Aujeszky’s disease virus – 7.50–7.80 lg TCID50/cm3.

Propagation of the Aujeszky’s disease virus isolate in continuous cell lines

The objective of this study was to investigate the cultural properties of Aujeszky's disease virus isolate and the optimization of the conditions of obtaining virus-containing material in the most prospective cell cultures. As a result, it was established that the study virus isolate is highly pathogenic for laboratory animals: rabbits, guinea pigs, and rats. The following continuous cell lines were sensitive to the virus isolate: MDBK, Taurus-1 and ВНК-21. CPE (cytopathogenic effect of viruses) nature was similar in different cell cultures. The ability for propagation in cultures of continuous cell lines of the test virus isolates reached the maximum value to 4-6 passage, equaling to 6.85-7.65 lgTCD50/cm3. The obtained results show that the dynamics of the virus isolate dynamics had no significant differences, and following the adaptation, the virus isolate maintained the stable inherent propagation activity level throughout the study. As the study result, the most sensitive cell culture Taurus-1 was selected at passaging, with the highest virus accumulation observed, the infection activity was 7.55±0.12 lg TCD50/cm3. The presence of Aujeszky's disease virus was confirmed by the bioassay and the other laboratory methods, including PCR (polymerase chain reaction). The PCR method allowed defining the virus genome in the virus-containing cultural and organ and tissue material. PCR allowed amplifying the target gene fragment with the size of 194 base pairs (b.p.) in samples containing Aujeszky's disease virus DNA. No non-specific reactions were observed; PCR products did not exhibit the expected size

Wild boar as the unlikely source of Aujeszky’s Disease virus for swine

In the introduction of this paper the virological definition of the SuHV-1, the etiological agent of Aujeszky’s Disease (AD) of swine, is presented. The importance of ADas an OIE listed disease is mentioned. The gE- deleted marker vaccine in combination with differentiating infected from vaccinated swine ELISA kit is characterized. It is worth to remember that Poland in 2019 will inform the Veterinary Commission of the EU about the freedom of AD in domestic pigs. The seroprevalence of AD in wild boar is variable, from very high occurrence in Mediterranean countries to low level or not existence in Northern Europe. According to several cited authors two subtypes of ADV are existing and characterised – subtype I in wild boar, not being pathogenic for wild boar, existing also in domestic swine, and subtype II occurring in swine and being for domestic swine very pathogenic. Other genetic data connected with pathogenicity of Aujeszky’s disease virus variants are also mentioned.