Optimization of immune electron microscopic diagnosis of potato virus A

Methods to obtain good clarified virus extract for immune electron microscopic diagnosis of potato virus A were standardized. Trapping or immunosorpiton of the virions, binding of antibodies by the immunosorbed virions on solid phase (decoration) and cross-linkge of virions with antibodies (clumping) in liquid phase depended on the pH of both the virus extraction buffer and the antiserum. Further, binding of coss-linked (clumped) virions on the grid was enhanced when it was pre-coated with protein A.