Antimurine retroviral effect of doxycycline

The tetracycline family is composed of several molecules whose antibacteria l properties are due to the fixation on the bacterial ribosomes. Among thos e, doxycycline is one of the most potent antibiotics for which additional f eatures have been recently discovered. Doxycycline has been found to inhibi t metalloproteinases, to decrease gelatinolytic and metastatic activities o f cancer cells, to have a "chondroprotective" effect in inflammatory arthri tides, and to have strong antimalarial properties. In this study, a murine retrovirus producing cell line (psi CRIP-pXTI) was incubated in variable co ncentrations of doxycycline. The retroviral titer of this cell line was mea sured by the ability to transfer resistance to G418 to NIH/3T3 cells. The r etroviral titer was significantly decreased by 70% when the packaging cells had been incubated with 25 mu M of doxycycline at 37 degrees C. The ID50 w as around 8 mu g/ml. Astonishingly, this effect was not observed at 32 degr ees C. The mechanism of this effect is still to be determined. It may be us eful to be aware of this effect for uncovering all of the possible antivira l qualities of doxycycline and its related molecules, such glycylcyclines o r anthracyclines. (C) 1998 Prous Science. All rights reserved.