Resistance of Subtype C HIV-1 Strains to Anti-V3 Loop Antibodies

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.