Mycophenolic acid inhibits replication of Type 2 Winnipeg, a cerebrospinal fluid-derived reovirus isolate.
BACKGROUND
The role of reoviruses in human disease is uncertain. Most identified cases are sporadic and asymptomatic or produce minor upper respiratory or gastrointestinal symptoms. In November 1997, a reovirus was isolated from the cerebrospinal fluid of a severe combined immune deficient infant in Winnipeg, Manitoba. RNA characterization and sequencing studies demonstrated this reovirus isolate to be unique. Thus, the virus was named Type 2 Winnipeg (T2W).


OBJECTIVE
Mycophenolic acid (MPA), a drug primarily used as an immunosuppressive agent, was assessed in the capacity to inhibit T2W viral growth.


METHODS
The effects of MPA on viral growth were determined by plaque reduction assays. Cells were treated with different MPA concentrations, infected with T2W and incubated at 37 degrees C for 0 h to 72 h. Virus titres were determined and compared with untreated controls.


RESULTS
Production of infectious T2W progeny decreased more than 99% at 3 microg/mL MPA compared with untreated controls. Inhibition was not caused by cell toxicity because there was no difference in cell viability. The 50% cell toxic dose was 30 microg/mL MPA.


CONCLUSIONS
MPA was able to inhibit viral growth of the novel reovirus T2W. Although MPA is usually used as an immunosuppressive agent, and despite the fact that T2W was isolated from an immunocompromised patient, these results suggest that MPA could have been used as a possible treatment at subimmunosuppressive doses. Animal studies to better define the antiviral and immunosuppressive activities of MPA (and its prodrug mycophenolate mofetil) appear warranted.
Hermann
Laura L
LL
Departments of Medical Microbiology and Infectious Diseases, and Physiology, University of Manitoba, Winnipeg, Manitoba.
Coombs
Kevin M
KM