Table 2: IC50s (ug/mL) of 15 different antibodies (columns) derived from subtype B and subtype A infected patients neutralizing the infectivity of psVs containing the subtype C and B V3 sequences in the SF162 Env backbone. For comparison, the IC50 values for a non-V3 Ab (b12) are as follows: clade B cons. (JR-FL) = 0.009 ug/mL; clade C cons. = 0.02 ug/mL, all others untested; which does not show as dramatic a difference in neutralization between the two psVs. 135 MPL23a is a subtype C primary isolate and is included as an example of IC50 values in non-neutralization-sensitive (“masked”) backgrounds. IC50 values are font-type coded as follows: bold >0.1 ug/mL; italic <0.1 ug/mL; bold/italic <0.01 ug/mL.

V3 sequence Anti-V3 mAbs from clade B infected patients Anti-V3 mAbs from clade A infected patients 2412 4117 2442 4148 2456 447 2191 2219 2128 3074 2557 2558 3019 3224 2601 c1. B cons (JR-FL) 0.0009 0.0055 0.0018 0.0053 0.0039 0.00054 0.0023 0.0012 0.0013 0.0055 0.0037 0.0049 0.0027 0.0051 0.12 clade A1 cons 2.81 14.4 0.027 0.068 0.083 0.58 0.043 0.029 >20 0.015 0.025 0.038 0.032 0.044 0.029 clade C cons >20 >20 >20 2.5 0.44 >20 0.59 0.15 >20 0.2 0.16 0.2 0.25 1.8 0.17 IC50 ratios B/C >22,000 >3,600 >11,000 470 113 >37,000 257 125 >15,000 36 43 41 93 345 1.4 135 MPI 23a* >20 >20 >20 >20 >20 >20 >20 >20 >20 8.0 >20 77.0 93.0 >20 >20

*Primary subtype C isolate.