A DNA vector comprises a first
DNA sequence which is complementary to at least part of an
alphavirus RNA genome and having the complement of complete
alphavirus DNA genome replication regions, and a second
DNA sequence encoding a paramyxovirus
protein, particularly a respiratory syncytial
virus fusion (RSV F)
protein or a RSV
F protein fragment that generates antibodies that specifically react with RSV
F protein, the first and second DNA sequences being under the transcriptional control of a
promoter, preferably a cytomegalovirus
promoter, which may include
Intron A. Such vectors also contain a further
nucleotide sequence located between the
promoter sequence and the
alphavirus sequence to enhance the immunoprotective ability of the RSV
F protein when expressed
in vivo. Such DNA vectors may be used to immunize a host against
disease caused by infection with RSV or other paramyxovirus, including a human host, by administration thereto, and may be formulated as immunogenic compositions with pharmaceutically-acceptable carriers for such purposes. Such vectors also may be used to produce antibodies for detection of RSV or other paramyxovirus infection in a sample.