Dear colleagues, could you please give me some suggestions for my research issue.

I want to determine what proteins of a bacterium are the main virulence factors which cause death for infected fish in challenge test. Our hypothesis is that once fish get infected, the bacterium would release these proteins into the fish body, probably these proteins would go to all fish organs through blood where they defeat all the immune system of the fish and end up killing the fish. We don't know which fish organs are the best for us to do proteomics. In literature, there were a variety of organs being used for this purpose, such as liver, kidney, spleen. Can blood be the best one.

Many thanks for your consideration