Viral stimulation of choline phosphotransferase in spleen microsomes

Choline phosphotransferase and phosphatidyl ethanolamine methyltransferase enzymatic activities (nmoles phosphatidyl choline/min/mg protein) have been determined in spleen microsomes of Rauscher virus infected BALB/c male mice at 5, 10, 14, and 21 days following inoculation of the virus. There is a significant stimulation of the choline phosphotransferase activity in the virus infected spleens with the peak of activity at about 10 days of viral infection. The specific activity of choline phosphotransferase is 10 times that of the phosphatidyl ethanolamine methyltransferase at 10 days of viral infection. There is a 51-fold increase over controls for the total microsomal choline phosphotransferase at 14 days of viral infection and only an 18-fold increase over controls for the phosphatidyl ethanolamine methyltransferase activity. There is a significant (P<0.001) increase over controls in the concentration of total phospholipid-P, phosphatidyl choline-P, and phosphatidyl choline-P fractions as separated by argentation chromatography of microsomes from spleens of mice infected with Friend virus or Rauscher virus for 14 days. The choline phosphotransferase and phosphatidyl ethanolamine methyltransferase specific activities in liver microsomes of 14 day Friend and/or Rauscher virus are unaltered during viral infection.