FIG. 1.

CON6 and CON-S were generated by using two group M consensus env genes that contain variable regions either from a wild-type B/C recombinant virus isolate (CON6) or minimal consensus elements (CON-S) in the V1, V2, V4, and V5 regions. The minimal variable elements and the subtype C sequence positions are shown as gray and black boxes, respectively. C, F, and I indicate the location of the cleavage, fusion, and intervening regions, respectively. gp145CFI and gp140CFI indicate the location of the deletions and truncations.