RECOMBINANT VACCINIA VIRUS EXPRESSION OF ANAPLASMA-MARGINALE SURFACE PROTEIN MSP-1A - EFFECT OF PROMOTERS, LEADER SEQUENCES AND GPI ANCHOR SEQUENCE ON ANTIBODY-RESPONSE

Anaplasma marginale surface protein MSP-1a was expressed by recombinan t vaccinia viruses with different promoters and as hybrid proteins. Tr anscription of msp1 alpha with PII late promoter resulted in more MSP- 1a than with P7.5 early-late promoter; however, mice immunized with th e,recombinants had similar antibody titres. Recombinants expressing hy brid MSP-1a with either a murine leukaemia virus or a trypanosomal gly coprotein signal sequence did not enhance antibody responses and resul ted in a diffuse intracellular distribution of MSP-1a which did not ac cumulate in the Golgi apparatus as was noted in the absence of these s ignal sequences. In contrast, antibody titres to MSP-1a in mice immuni zed with a recombinant virus expressing hybrid MSP-1a with a trypanoso mal GPI anchor signal sequence were significantly increased over all o ther constructs.