FIG. 3.

Three strategies for designing NNSV vectors. In panel A, a complete virus (in this case, HPIV3) is modified by insertion of a transcription cassette encoding a foreign antigen (measles virus [MeV] HA glycoprotein). In panel B, a NNSV (BPIV3) is modified by deleting its surface glycoprotein genes (F and HN) and replacing them with those (F and HN) from the target pathogen (HPIV3), resulting in an antigenic chimeric virus (B/HPIV3). In panel C, an antigenic chimeric virus (B/HPIV3) is modified by insertion of a transcription cassette encoding a foreign glycoprotein (HRSV F). In each case (A to C), the coding sequence of the foreign glycoprotein(s) must be under the control of GS and GE signals that are compatible with the vector backbone.