Comparison of integrin and HSPG membrane protein affinity of BHK cells with different growth characteristics against FMD viruses

Foot and Mouth Disease (FMD) is a contagious viral disease of cloven-hoofed animals that causes great economic losses. Vaccination against FMD is one of the most important strategies in the fight against the disease in Türkiye. FMD vaccines are currently produced in large volumes of suspensed BHK 21 cell cultures at the Foot and Mouth Institute. Investigating the antigen production capacities of the cell used in vaccine production is important in terms of reducing the cost of vaccine production. In this study, the most suitablecell line for vaccine production was tried to be determined by comparing three BHK 21 cell lines in terms of their cellular receptor expression and antigen production capacity. In this study, working stocks of BHK 21 An31, BHK 21 An73 and BHK 21 An5 cells, which are originated from BHK 21 C/13 cell line and used in cell culture adaptation of FMD virus and in vaccine production, were created. The characteristic features of these three cell lines were determined by daily growth curve, doubling time, and plating efficiency studies. FMD virus strains OTUR/07, AIRN/17, Asia1TUR/15 were produced in these cell lines and the amount of 146S particles, which is the determining factor of immunity in the FMD vaccine, was measured by the sucrose gradient density method. The expression of ITGβ3, ITGβ6 integrin receptors and HSPG2, SDC1 heparan sulfate transmembrane proteins of these three BHK 21 cell lines at certain hours after FMD virus inoculation was compared with real-time PCR method. As a result of the study, it was seen that the infective titer and 146S particle values were higher in BHK 21 An73 cell line than in other cell lines. According to the real-time PCR results, it was observed that the expression of ITGβ3, ITGβ6 integrin receptors and HSPG2, SDC1 heparan sulfate transmembrane proteins were high in all three cell lines at the first and sixth hours after infection of three different FMD virus strains. However, at the twelfth and eighteenth hours, it was observed that the expression gradually decreased, the expression of the highest number of BHK 21 An73 cells in terms of the studied receptors was the highest in three BHK 21 cells, and SDC1 was expressed less in the receptors than the others.