Nonreplicating viral vectors as potential vaccines: recombinant canarypox virus expressing measles virus fusion (F) and hemagglutinin (HA) glycoproteins.

The development of canarypox virus (CPV) recombinants expressing the hemagglutinin (HA) and fusion (F) glycoproteins of measles virus (MV) is described. Inoculation of the CPV-MV recombinants into avian or nonavian tissue culture substrates led to the expression of authentic MVF and MVHA as determined by radioimmunoprecipitation and surface immunofluorescence. In contrast to avian-derived tissue culture, no productive replication of the CPV recombinant was evident in tissue culture cells derived from nonavian origin. On inoculation of dogs, a species restricted for avipoxvirus replication, the recombinants elicited a protective immune response against a lethal canine distemper virus (CDV) challenge. The level of MV neutralizing antibodies and the level of protection induced against CDV challenge achieved by the host-restricted CPV vector were equivalent to that obtained by vaccinia virus vectors expressing the same MV antigens.