Susceptibility of human herpesvirus 6 to antiviral compounds by flow cytometry analysis.
BACKGROUND
The emergence of human herpesvirus 6 (HHV-6) as a human pathogen led to the possibility of specific therapy against HHV-6 and the development of standardized susceptibility assays of HHV-6 to antivirals.


METHODS
We have developed a flow cytometry method to analyze the multiplication of the HST strain of human herpesvirus 6 (HHV-6) variant B in vitro using monoclonal antibodies specific to virus proteins. This method was subsequently used to determine the sensitivity of HST multiplication in MT4 cells to four antiviral compounds of three different classes: acyclovir (ACV) and ganciclovir (GCV), two acyclic guanosine analogs; cedofovir (CDV), an acyclic nucleoside phosphonate; and phosphonoformic acid (PFA), a pyrophosphate analog.


RESULTS
The 50% inhibitory concentrations (IC(50)) of ACV, GCV, CDV, and PFA determined by flow cytometry assay were 25.3, 6.4, 0.95, and 6.0 microM, respectively (5.7, 1.6, 0.3, and 1.8 microg/ml, respectively). These data together with the results of cytotoxicity assays confirmed the high efficiency and selectivity of CDV and PFA against HHV-6 B in vitro, suggested by previous results.


CONCLUSIONS
Our flow cytometric assay appeared as a reproducible specific method to characterize HHV-6 susceptibility to antiviral compounds. It can be considered as a convenient alternative to the other immunologic and DNA hybridization assays used for that purpose.
Manichanh
C
C
Laboratoire de Virologie, CERVI, Groupe Hospitalier Pitié-Salpétrière, Paris, France.
Grenot
P
P
Gautheret-Dejean
A
A
Debré
P
P
Huraux
J M
JM
Agut
H
H
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface / Q000032:analysis / Q000276:immunology; D000956:Antigens, Viral / Q000032:analysis / Q000276:immunology; D000998:Antiviral Agents / Q000494:pharmacology*; D000077404:Cidofovir; D003596:Cytosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry / Q000379:methods / Q000592:standards; D017245:Foscarnet / Q000494:pharmacology; D015774:Ganciclovir / Q000494:pharmacology; D006566:Herpesviridae Infections / Q000188:drug therapy*; D015654:Herpesvirus 6, Human / Q000187:drug effects / Q000254:growth & development* / Q000276:immunology; D006801:Humans; D066298:In Vitro Techniques; D007963:Leukocytes, Mononuclear / Q000166:cytology* / Q000821:virology*; D063065:Organophosphonates; D009943:Organophosphorus Compounds / Q000494:pharmacology*; D015203:Reproducibility of Results
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D000956:Antigens, Viral; D000998:Antiviral Agents; D063065:Organophosphonates; D009943:Organophosphorus Compounds; D017245:Foscarnet; D003596:Cytosine; D000077404:Cidofovir; D015774:Ganciclovir