Fig. 5
Accommodation of long V1, associated with viral fitness loss, by compensatory mutations. a Viral replication of clonal viral isolates from month 7 versus month 11 with the horizontal bars representing the median p24 values over the viruses isolated at that time point. b Linear regression between viral replication, expressed as p24 production per day, and V1 length for viruses from month 7 and 11. Virus isolates are colored based on number of additional cysteine residues in their V1 (0: blue, 2: red, 4: green). c V1 sequence alignment of representative virus isolates from individual D16916 with 0, 2 and 4 additional cysteines (clones D16916.7.2C9, D16916.7.1E3, D16916.11.2D1), as well as HIV-1LAI, HIV-1LAI mutants 1 and 2, and their revertants. d CA-p24 ELISA of HIV-1LAI and mutant virus stocks, produced by transient transfection of HEK293T cells. e TZM-bl cells were infected with 500 pg CA-p24, and infectivity was measured after 48 h infection. f Schematic V1/V2 topology. β-strands are depicted as purple arrows and disulphide bonds as yellow lines. The V1 and V2 loop are indicated in green and blue lines, respectively. The substitutions designed to restore the epitopes for bNAbs PG9 and PG16 are underlined and the locations of the HIV-1LAI reversions are indicated in bold. g Ribbon diagram of f with the position of the HIV-1LAI reversions indicated as red spheres (except L → P at the fourth position of the insert) and labeled according to their position in the linear sequence. Note that the elongated V1 with additional cysteine residues is not depicted