EN
The purpose of the study was to utilise rabbit kidney cells (RK13) infected with equine influenza virus as an alternative source of viral antigens in ELISA. Peroxidase linked assay confirmed multiplication of equine influenza virus in RK 13 cells. To optimise the equine serum dilutions, one negative and one positive sera (HI titer 1,280 for both antigens) were tested. The sera were examined in serial dilutions and a decrease in OD values in both cases was related to the dilution. Finally, dilution 1:160 was considered to be the optimal as the negative serum showed low level of nonspecific binding, while the positive serum gave a high OD reading. These conditions were applied to test 36 equine sera of the HI titers ranging from 20 to 2,560 and the results of cell based ELISA and HI test were compared. OD values for HI negative sera ranged from 0.025 to 0.074 for H7N7 and from 0.042 to 0.117 for H3N8. OD values for sera positive in HI test ranged between 0.058 and 1.013 for H7N7 antigen and from 0.048 to 1.01 for H3N8 antigen in cell based ELISA. The results of both tests showed correlation r = 0.785 for H7N7 and r = 0.882 for H3N8. These results proved that RK13 cells can be used in cell based ELISA to detect antibodies specific for equine influenza virus. The advantage of the cell based ELISA can also be the fact of detecting antibodies specific to NS viral proteins; however the test needs to be optimised.