Bovine immunodeficiency virus (BIV) based vectors

A vector construct comprising:

• a promoter linked to a first BIV R region;
• a BIV U5 element linked to the first BIV R region;
• a packaging sequence;
• a transgene;
• and
• a BIV U3 element linked to a second BIV R region, wherein the promoter initiates RNA transcription of the vector construct, and at least one of vpw, vpy and tat is deleted from said construct.

A cell comprising a BIV vector construct comprising:

• a) a DNA segment from a BIV genome,
• b) a packaging sequence to package RNA into virions,
• c) a first promoter operably linked to the DNA segment, and
• d) a transgene operably linked to a second promoter, wherein at least one of vpw, vpy and tat is deleted from said construct.

A cell comprising a vector construct comprising:

• a promoter linked to a first BIV R region;
• a BIV U5 element linked to the first BIV R region;
• a packaging sequence;
• a transgene;
• and
• a BIV U3 element linked to a second BIV R region, wherein the promoter initiates RNA transcription of the vector construct, and at least one of vpw, vpy and tat is deleted from said construct.