Fluorescence anisotropy of viruses treated with formaldehyde and dimethyl-sulfoxide

The fluorescence anisotropy changes observed in A-1 (H1N1) influenza and Sendai parainfluenza viruses in aqueous suspensions when formaldehyde (0.1 to 1.0 p.c.) and dimethyl-sulfoxide (0.3 to 5.0 p.c.) were added, using both intrinsic fluorescence of viral proteins and that of the membrane fluorescent probe--DPH, showed significant differences with regard to the virus and the history of the suspensions used, allowing under rigorous standardized conditions the use of fluorescence anisotropy measurements for viral antigen and vaccine control.