TWENTY-SECOND ANNUAL EASTERN FISH HEALTH WORKSHOP ROYAL PAVILLION RESORT, ATLANTIC BEACH, NC MARCH 18 - 20, 1997 Characterization of the Largemouth Bass Virus in Cell Culture and a Comparison with Other Iridoviruses Thea O. Piaskoski and John A. Plumb Southeastern Cooperative Fish Disease Laboratory, Department of Fisheries and Allied Aquacultures, Auburn University, Auburn, AL 36849 A newly isolated largemouth bass iridovirus (LMBV) was characterized by cell culture and protein analysis. Viral titer and replication patterns were used to analyze fish cell susceptibilities to LMBV, optimum cell culture for virus isolation, and optimum replication temperature. The bluegill fry-2 (BF-2) and fathead minnow (FHM) cell lines were most susceptible to LMBV. Viral induced CPE was present first in these cell lines and they produced the highest viral titers. Optimum temperature range for LMBV replication in infected BF-2 cells was 25-30oC. In BF-2 cells, LMBV reached a maximum titer of 108.5TCID50/mL, 24h post infection. LMBV lost infectivity when treated with ether indicating the presence of an outer lipid envelope that is essential for optimal infectivity. Titers of virus samples tested from pH 3 to 9 remained constant at 108.5TCID50/mL. Sensitivity to ether and resistance to pH extremes are properties shared with other fish iridoviruses. Viral proteins of LMBV, frog virus-3 (FV-3), lymphocystis disease virus (LCDV-1), and sheatfish iridovirus (SFV) were characterized by PAGE. Protein profiles of all viruses tested were similar although distinctions were made between viruses on number, intensity and migration distances of the polypeptides. The virus shared major structural polypeptides including viral protein 48 believed to be the major capsid protein. LMBV was most similar to FV-3, the prototype of Ranavirus genus within the family Iridoviridae. No proteins were stained with the periodic acid - silver stain used for glycoproteins. LMBV should be tentatively grouped in the Ranavirus genus pending further investigation. Return to 22nd Annual Eastern Fish Health Workshop Return to Leetown Science Center Home Page