SIGLEC-10, CD1B, AND PALLADIN ARE DIFFERENTIALLY EXPRESSED BETWEEN HIV+ PROGRESSORS AND NONPROGRESSORS

Description of the problem and objectives: HIV plasma viremia and CD4+ lymphocyte counts dictate the classification of HIV+ disease progression to Acquired Immunodeficiency Syndrome (AIDS), i.e. progressor (PR) vs. non-progressor (NP). In the absence of HAART, NP CD4+ counts remain stable and viral load is substantially reduced. Recent data affirms that NPs exhibit decreased trans-infection efficiency due to reduced cholesterol levels1. Further transcriptome analysis of Multicenter AIDS Cohort Study (MACS) antigen presenting cells (APCs) reveals vastly different expression profiles between NPs and PRs for Siglec-10, CD1B, and Palladin (PALLD). While the explicit mechanism remains elusive, our aim is to elucidate the genetic origin of NP viremic control. We have hypothesized that Siglec-10, CD1b, and Palladin are differentially expressed between HIV+ PRs and NPs. 

Methods used: MACS CD14+ monocytes were cultured with IL-4 and GM-CSF to yield immature dendritic cells (iDCs). Protein expression of Siglec-10, CD1B, and PALLD in seronegative (SN), PR, and NP iDCs has been assessed using flow cytometry. RT-qPCR and TaqMan® genotyping assays in iDCs are used for corroboration of gene expression data from the transcriptome findings. 

Results: Flow cytometry data show no significant difference in Siglec-10, CD1b, or PALLD protein expression between PR and NP donors. RT-qPCR SyBr green primers for all targeted genes resulted in artefactual amplicons for control and experimental melt curves. Comparison of CT values could not be interpreted confidently. IDT Taq-Man® primers were subsequently utilized. Analysis of qPCR data shows significant differences in CD1b and PALLD expression levels between NPs and PRs (p < 0.05). Haplotype analysis of CD1b Single Nucleotide Polymorphisms (SNPs) between NP, PRs, and SN individuals via TaqMan Genotyping was not statistically significant. 

Public Health Significance: Identifying the underlying genetic factors that drive HIV-1 disease progression could reveal potential therapeutic targets with the long term aim of improving HIV health outcomes.