Kinetics of gp41-specific antibody titers and contribution of Fc mediated gp41 specific antibody responses following SHIV-SF162P3 challenge.

<p>The level of gp41 specific antibody subclass over time was measured by Luminex in the plasma of the 4 infected monkeys that received the EC antibodies as well as in one monkey that received the HIV-NEG antibodies and is reported as mean fluorescence intensity (A). Antibodies were purified from the rhesus monkeys that received the EC antibodies or the HIV-NEG antibodies and tested for their ability to recruit monocytes to mediate phagocytosis (B) or to activate NK cell measured as a release of CD107a, MIP1β and IFNγ (C) 2 weeks prior the antibody transfer and at day 1, 3, 7, 14, 21 and 28 post antibody transfer.</p

Antibodies purified from the elite controller selected for the <i>in vivo</i> study display a wide range of innate immune recruiting properties.

<p>Large quantities of antibodies were purified from the plasma of EC10 and assessed for their neutralizing capacity in a TZM-bl assay (A) and in a primary CD4 T cell assay (B). IgG HIV-binding titer against YU-2, SF162 gp120s, SHIVgp140 SF162p3 and gp41 was assessed (C) along with ADCVI activity (D) against a tier 2 (JRCSF), a tier 1A (SF162) and the challenge virus (SHIV-SF162P3). Purified b12 and a pool of antibodies purified from HIV-negative individuals were used as positive and negative controls, respectively. HIVIG was used as a positive control for testing gp41-binding titer. Antibodies purified from the plasma of EC10 were also evaluated for their ability to induce ADCP against a tier 2(JRCSF), a tier 1A (SF162) virus as well as against gp41 (E) and for their ability to induce complement activation as measured by C3b deposition on YU-2 or SF162 gp120 pulsed CEM cell line using HIVIG and a pool of antibodies purified from healthy individuals as positive and negative controls, respectively (F). A minimum of 2 separate experiments was performed to confirm the innate immune recruiting properties of the antibodies from the selected EC.</p

Kinetics of gp120-specific antibody titers and innate immune recruiting properties of antibodies following SHIV-SF162P3 challenge.

<p>ELISA was used to test the level of gp120-specific antibodies in the plasma of infected rhesus macaques (A) that received purified antibodies from either the pool of HIV-negative individuals (<i>i</i>) or the elite controller (<i>ii</i>). Optical Density (OD) values are reported. The level of gp120 specific antibody subclass over time was measured by Luminex in the plasma of the 4 infected monkeys that received the EC antibodies as well as in one monkey that received the HIV-NEG antibodies and is reported as mean fluorescence intensity (B–E). Antibodies were purified from the rhesus monkeys that received the EC antibodies (<i>i</i>) or the HIV-NEG antibodies (<i>ii</i>) and tested for their ability to recruit NK cells to mediate ADCC (F) or to recruit monocytes to mediate phagocytosis (G) 2 weeks prior the antibody transfer and at day 1, 3, 7, 14, 21 and 28 post antibody transfer. NK cells isolated from 2 separate donors were used to assess ADCC and 2 separate experiments were performed to measure the phagocytic activity.</p

Polyclonal antibodies from naturally infected donors have a wide range of non-neutralizing anti-viral activities.

<p>Antibodies purified from the plasma of 15 different elite controllers (labeled EC-1 to EC15) were tested for their ability to bind to gp120 by ELISA, shown as the inverse of EC50 (A), to mediate ADCVI, measured as a percent of inhibition of viral replication (B) and to neutralize HIV virus (JRCSF), measured as an inverse of EC50 (C). The correlation plots show the relationship between gp120-specific antibody titers from elite controllers and ADCVI activity (D), or virus neutralization (E) as well as the association between the neutralization and ADCVI activity of antibodies (F). The elite controller from which the purified antibodies had the greatest innate immune recruiting properties in the absence of neutralization, EC10, was selected for passive transfer into macaques and is highlighted in gray. A minimum of 2 separate experiments was assessed to select the EC antibodies that had the best activity.</p

Kinetics of plasma viremia following SHIV-SF162P3 challenge.

<p>50 mg/kg of antibodies purified from the selected elite controller (A) or from HIV-negative individuals (B) were passively transferred intravenously one day prior to the challenge with SHIV-SF162P3 in 5 rhesus macaques each. The plasma viremia was measured 14 days before and 1, 3, 7, 14, 21, 28, 56 and 84 days after antibody transfer. No viremia was detected in the animal that received 25 mg/kg of the b12 monoclonal antibodies used as a positive control. The area under the curve (AUC) of viral loads was measured in the 4 infected monkeys that received the EC antibodies and the 3 infected monkeys that received HIV-NEG antibodies (C). An unpaired two-tailed t-test with 95% confidence intervals was used to compare the AUC between both groups.</p