Wh. Wu et al., EXPRESSION OF ALEUTIAN MINK DISEASE PARVOVIRUS CAPSID PROTEINS IN A BACULOVIRUS EXPRESSION SYSTEM FOR POTENTIAL DIAGNOSTIC USE, Journal of veterinary diagnostic investigation, 6(1), 1994, pp. 23-29
A 2.3-kb cDNA clone encoding Aleutian mink disease parvovirus (ADV) st
ructural proteins VP1 and VP2 was inserted into the polyhedron gene of
Autographa californica nuclear polyhedrosis virus (AcNPV) and express
ed by the recombinant virus, AcADV-1, in Spodoptera frugiperda-9 cells
. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and wester
n immunoblot analysis (WIA) indicated that synthesis of both VP1 and V
P2 was being directed by AcADV-1. Fluorescence microscopic examination
of AcADV-1-infected S. frugiperda-9 cells indicated that the recombin
ant protein was present within the nucleus of the cells, and electron
microscopic examination of these cells revealed the presence of small
particles 23-25 nm in diameter. Structures resembling empty ADV capsid
s could be purified on CsCl density gradients, thus indicating that th
e ADV proteins were self-assembling. The antigenicity of recombinant V
P1 and VP2 was evaluated by WIA. Sera collected from 16 mink prior to
infection with ADV did not react with VP1 and VP2. Ten sera collected
from mink with counter current immunoelectrophoresis (CIE) titers grea
ter than 4 (log2) reacted with VP1 and VP2 in WIA. Two of 6 sera with
CIE titers of 4 and 1 of 14 sera with CIE titers < 4 reacted with the
recombinant proteins. These results suggest that baculovirus recombina
nt ADV capsid proteins may be useful as diagnostic antigens.