We have discovered a new type of abortive replication in Vero cells in
fected with fowl plague virus. In these cells there is an enhanced spl
icing of the colinear mRNAs of segment 7 and presumably also of segmen
t 8, leading to an extreme overproduction of M2 and NS2 proteins. The
cleavage of the hemagglutinin (HA) into HA1 and HA2 and the processing
of its carbohydrate side chains are markedly retarded and incomplete.
Although some of the HA is incorporated into the plasma membrane, lea
ding to a positive hemadsorption, most of it accumulates in a discrete
compartment close to the nuclear membrane, representing presumably th
e reticuloendothel and/or the Golgi network. Neuraminidase activity in
Vero cells is extremely low. The nucleoprotein is normally released f
rom nuclei late in infection. Very little infectious virus is released
, and its spread is highly impeded. (C) 1995 Academic Press, Inc.