Determination of virulence associated immunogenic proteins in some of strains.

Lactococcosis disease incident caused by has been increased with increasing aquaculture productions and outbreaks of the disease have become a threat on farmed species. To prevent lactococcosis, inactivated vaccine has been used, however, it only provides protection when given by injection. Other than inactivated vaccine, various vaccines such as subunit vaccines can be developed. In the present study, total protein profile of 43 strains of isolated from fish, milk and cheese by SDS-PAGE and virulence associated immunogenic proteins of strains using western blot with hyper-immune rabbit sera were determined. After analyzing whole-cell lysate protein of strains with SDS-PAGE, protein bands were ranged between 8.00 and 140.00 kDA. Among strains, variable protein bands were ranged between 17.00 and 48.00 kDa with some variability in the staining intensity of the protein bands and formed in 6 clusters. The immunogenic protein bands were ranged between 25.00 - 75.00 kDa. Only a variable and highly immunogenic protein band was observed between 40.00 and 45.00 kDa. Most of the strain including Lgper had 44.00 kDa immunogenic protein while nonvirulent ATCC strain had 42.50 kDA immunogenic protein. Predominant immuno-reactive proteins encoded by genes can be used as a subunit vaccine.