CROI 2015 Program and Abstracts

Abstract Listing

Poster Abstracts

require adaptation after infection of macaques and do not represent the diversity of circulating HIV-1 variants. Type-I interferon (IFN) is an innate immune factor that induces multiple host restriction factors that could contribute to poor replication of SHIVs, and the role of IFN in SHIV replication in macaques has not been well defined. Methods: We examined 8 SHIVs, including 3 representing pathogenic SHIVs adapted for replication in macaques, 1 SHIV encoding culture-adapted HIV-1, and 4 SHIVs encoding HIV-1 Envs representing circulating variants for the ability to replicate in macaque lymphocytes. During a 12-day time course, we measured viral replication kinetics during the logarithmic growth phase and sensitivity to IFN for each SHIV. Results: We found that the SHIVs tested exhibited a range of replication kinetics and that the mean replication slope of SHIVs encoding Envs adapted in culture or in macaques was significantly greater than that of SHIVs encoding Envs from circulating variants (1.01 vs. 0.74, p =0.03). We also found that replication slope positively correlated with resistance to IFN treatment (Spearman r = 0.88, p = 0.007). By generating chimeras between a pathogenic SHIV and one derived from a circulating HIV-1 variant, we found that high replication kinetics and resistance to IFN treatment mapped to HIV-1 Env. Conclusions: The findings of this study indicate that HIV-1 Env is a major viral determinant of high replication kinetics of SHIVs in macaque cells and that replication kinetics play an important role in the ability of SHIVs to overcome the IFN response. SHIVs that have been adapted in macaques exhibit high replication kinetics and resistance to IFN, which may contribute to their ability to establish persistent infection in macaques. These studies suggest the presence of an IFN-induced factor(s) that can be antagonized by Envs that facilitate rapid replication. 281 Elevated IFN- γ in HIV Patients Using a Novel Assay for Adaptive and Innate Immunity Michelle K. Yong 1 ; Paul Cameron 1 ;Tim Spelman 2 ; Julian Elliott 1 ; Christopher Fairley 4 ; Jeffrey Boyle 3 ; Misato Miyamasu 3 ; Sharon R. Lewin 1 1 Monash University/Alfred Hospital, Melbourne, Australia; 2 Burnet Institute, Melbourne, Australia; 3 Qiagen, Melbourne, Australia; 4 Melbourne Sexual Health Centre, Melbourne, Australia Background: HIV infection is characterised by immune activation of both the adaptive and innate immune responses that persists in patients following antiretroviral therapy (ART) and has been associated with poor CD4+ T-cell recovery and serious non-AIDS events (SNAE). The aim of this study was to evaluate adaptive and innate immunity in HIV- infected patients prior to and following ART. Methods: A cross sectional study of HIV and non-HIV infected individuals were recruited from The Alfred Hospital and the Melbourne Sexual Health Centre (MSHC), Melbourne Australia. HIV-infected patients were either naïve to ART or on suppressive ART for 12 months. Whole blood was assessed using the Quantiferon Monitor (QFM) assay containing 1:1 IU/ml of anti-CD3 (T-cell receptor ligand) and R848 (TLR7 ligand). We also assessed 0.1:0.1 IU/ml of anti-CD3 and R848 (QFM 1:10). Production of IFN- γ levels (IU/mL) was measured in supernatant by ELISA. Results: We recruited HIV-infected participants (n=79; n=20 naïve to ART and n=59 on suppressive ART; median CD4 of 557 cells/ m l (IQR 403-729 cells/ m l) and median age of 45 years (IQR 34-55 years) and healthy controls (n=229). HIV-infected participants on ART were older (47 vs 31 years, p<0.001) and had a longer duration of HIV infection (12.3 vs 1.4 years, p=0.004). IFN- γ production with QFM 1:10 was significantly higher in HIV infected patients compared to healthy controls (median IFN- γ 512 vs 223 IU/ml, p<0.0001), and this difference remained whether in participants both on or off ART (median IFN- γ 512 and 593 IU/ml respectively, K-Wallis test of difference p=0.0004). IFN- γ production in patients on ART was significantly higher in participants with CD4 >350 cells/ m L compared to a CD4<350 cells/ m L (561 vs 259 IFN IU/ml p=0.02). Patients with CD4 counts <350 had responses similar to healthy controls. IFN- γ production was significantly higher in male HIV-infected patients (median IFN 542 vs 77 IU/ml p=0.02). There were no known associations between IFN responses and age (p=1.0), viral load (p=0.56), nadir CD4 count (p=0.6) or duration of HIV infection (p=0.18). Using a multivariable analysis with 6 variables, neither CD4 nor sex were independently predictive of IFN- γ production. Conclusions: Using a high throughput assay which assesses both adaptive and innate immunity, we showmarked increases in IFN- γ production in HIV-infected patients both on Background: LILRA3 is an immunostimulatory molecule which conditionally induces proliferation in CD8+ T-cells and NK-cells via the stimulation of monocytes. LILRA3 has a deletion allele whose presence is a risk factor for HIV. Therefore, we believe that LILRA3 plays a role in viral immunity and want to study how LILRA3 is regulated. Methods: From a panel of TLR agonists, ssRNA40 is a major inducer of LILRA3 (not shown). To confirm this, we used ssRNA41 as additional control and studied this regulation in 8 donors. We magnetically isolated CD14 + monocytes after stimulation and analyzed LILRA3 levels in both CD14 + and CD14 - populations (n=3). Monocytes of healthy donors (n=29), HIV-untreated (n=19) and HIV-treated (n=22) patients were stimulated with ssRNA40 and analyzed for LILRA3. Cohorts were segregated according to genotype ( LILRA3 +/+ and LILRA3 +/- ). Mann-Whitney test was used for intra-group LILRA3 expression. Kruskal-Wallis test was used for inter-group LILRA3 expression among LILRA3 +/+ . In a second cohort, monocytes of healthy donors (n=13), HIV-untreated (n=16) and HIV-treated (n=11) patients received ssRNA40 or LPS (100 ng/mL). One-tailed Spearman analysis was used to calculate correlation between LILRA3 expression and virus loads and CD4 counts. Results: TLR8 agonist ssRNA40 is a potent inducer of LILRA3 (Figure 1A). This process occurs mainly in monocytes (Figure 1B). By segregation of cohorts into LILRA3 genotypes, we observed that ssRNA40-induced LILRA3 is dependent upon its gene dosage, with heterozygotes expressing less LILRA3 (Figure 1C). Among the LILRA3 +/+ donors, the TLR8-induced LILRA3 in HIV untreated patients was abrogated in comparison to the robust responses of healthy controls. LPS induced less LILRA3 than ssRNA40 among healthy controls (not shown), but remain at similar low levels for HIV untreated patients. We hypothesized that LILRA3 is helpful in controlling virus infections and that ssRNA40 and/or LPS induction of LILRA3 should correlate negatively to virus load and positively to CD4 counts, and indeed they do in untreated patients (Figure 1D). Finally, LILRA3 itself can induce a host of proinflammatory genes and can alter the antigen presentation machinery of monocytes (not shown). and off ART. Further research is warranted to determine if changes in Quantiferon Monitor are also associated with SNAEs. 282 TLR8 Regulation of LILRA3 Is Abrogated in HIV Infection and Correlates to CD4 Counts and Virus Loads Hui Zhi Low ; Gerrit Ahrenstorf;TorstenWitte Hannover Medical School, Hannover, Germany

Poster Abstracts

238

CROI 2015