Objective—To evaluate cytotoxicity and antiviral
activity of recombinant human interferon alfa-2a and
recombinant human interferon alfa-B/D hybrid against
cytopathic and noncytopathic bovine viral diarrhea
virus (BVDV), infectious bovine rhinotracheitis virus
(IBRV), and vesicular stomatitis virus (VSV) in vitro.
Sample population—Primary bovine testicular cells
and Mardin Darby bovine kidney cells.
Procedures—To evaluate cytotoxicity, cells were added
to serial dilutions of each interferon. To evaluate antiviral
activity of each interferon, interferons were serially diluted
1:10, and tissue culture cells were added; virus was
then added at 3 time points. Prevention of viral infection
by interferon was defined as failure to induce cytopathologic
effect for VSV, IBRV, and cytopathic BVDV and failure
to detect virus immunohistochemically for cytopathic
and noncytopathic BVDV.
Results—No evidence of cytotoxicity in either cell
line was detected after incubation with interferon alfa-
2a or interferon alfa-B/D. However, reduced growth
rates of tissue culture cells were detected for each
interferon when undiluted interferon was tested.
Comparable and profound antiviral activities against
cytopathic and noncytopathic BVDV were evident for
each interferon. Interferon alfa-2a and interferon a-B/D
had comparable antiviral activities against VSV.
Neither interferon had antiviral activity against IBRV.
Conclusions and Clinical Relevance—The safety
and marked in vitro antiviral activity against noncytopathic
BVDV, cytopathic BVDV, and VSV suggest that
interferons alfa-2a and alfa-B/D may be useful for
treatment of natural disease after infection with these
viruses. (Am J Vet Res 2004;65:871–874)