Virus photoinactivation in stroma-free hemoglobin with methylene blue or 1,9-dimethylmethylene blue

Photoinactivation of vesicular stomatitis virus (VSV) in stroma-free hemogl obin (SFH) was carried out using methylene blue (MB) or 19-dimethylmethylen e blue (DMMB). The VSV was more sensitive to inactivation by 660 nn light w ith 1 mu M DMMB than with the same concentration of MB. Under conditions th at inactivated 6 log,, of VSV, the methemoglobin content (Met-Hb[%]) and P- 50 of hemoglobin were changed by 1 mu M MB phototreatment but were not chan ged by 1 mu M DMMB phototreatment. The migration of hemoglobin during elect ophoresis and the activity of superoxide dismutase were? not changed by NIB or DMMB phototreatment. In contrast to the results obtained with DMME at 6 60 mm, 580 mm irradiation of SFH with DMMB resulted in a significant increa se of Mel-Nb(%) under conditions that only inactivated 1.19 log(10) VSV. Th e 580 mn irradiation primarily activates the dimer and higher-order aggrega tes of the dyes, while 660 nm irradiation primarily activates the monomer, These results indicate that the monomer form of DMMB can effectively inacti vate viruses without damage to SFH.