Factors Associated with the Development of Cross-Reactive Neutralizing Antibodies during Human Immunodeficiency Virus Type 1 Infection

Cross-NAb responses in the UW/CFAR cohort. Values represent the plasma dilution at which 50% neutralization was detected. Plasma samples were tested in a dilution range of 1:20 to 1:2,560. Gray-shaded boxes indicate neutralization of a particular isolate by the indicated plasma sample. (-), 50% neutralization was not recorded at a 1:20 plasma dilution. The times of infection for this cohort are unknown. TO, time point (in years) after enrollment at which the plasmas were collected and tested for neutralizing activity. Values listed in the breadth column are the percentages of the isolates tested that each plasma neutralized (i.e., the breadth of neutralization). Clade B viruses that are part of a panel of viruses created to evaluate the anti-HIV neutralizing responses elicited during infection or during immunization (17) are indicated by an asterisk. Cl. A, clade A.

Peptide competition neutralization assays. (A to F) Serially diluted plasmas were preincubated with the consensus clade B peptides corresponding to various regions of the HIV Env before use in neutralization assays against the primary isolate SF162. (G) Competition of plasma VC10028 using the 4E10 and a scrambled 4E10 peptide with the JRFL virus. A reduction in neutralization after preincubation with peptides indicates that the plasma contains NAbs directed at the corresponding regions of the HIV Env. The breadth of neutralization is indicated in parenthesis after each plasma's code. Ab, antibody.

(A) Contribution of anti-V1, anti-V2, or anti-V3 antibody to the plasma's neutralizing activity against SF162. (B) Contribution of V3-directed antibodies to the plasma's overall neutralizing activity against six primary HIV-1 isolates. The values indicate the percent reduction of the plasma's neutralizing activity against the indicated isolates following the preincubation of the plasma with the indicated peptides. TSI, the time since infection (in years) that plasmas were collected in the Vanderbilt cohort; (-), no reduction in the plasma's neutralizing activity was recorded; ND, the plasma has no neutralizing activity against the indicated virus.

Contribution of anti-CD4-BS antibodies to plasma-neutralizing activities. Plasmas were incubated with beads coated with either WT gp120 or gp120 with a mutated CD4-BS. The flowthrough and the eluted antibodies were tested for neutralizing activity against HIV. (A and B) Sample from patient VC10042; (C and D) sample from patient VC10014; (E and F) sample from patient CC1161; (G and H) sample from VC10002. Flowthroughs (A, C, E, and G) and eluted antibodies (B, D, F and H) are shown. Nondepleted, neutralization curves obtained with unadsorbed plasmas; WT depleted, plasma flowthroughs from WT gp120; BS-mutant depleted, plasma flowthroughs from the CD4-BS mutant gp120.

Presence of 2F5- or 4E10-like NAbs in plasma. (A) Values indicate the percent reduction in each plasma's neutralizing activity against SF162 following the preincubation of plasma with either r2F5 or 4E10 peptide. (B) The percent reduction in each plasma's neutralizing activity against six primary isolates following the preincubation of the plasma with the 4E10 peptide. (-), no reduction was recorded; ND, the plasma does not neutralize the indicated virus.