Spontaneous control of HIV-1 viremia in a subject with protective HLA-B plus HLA-C alleles and HLA-C associated single nucleotide polymorphisms

A fast and reliable method for detecting SNP rs67384697 (Hsa-miR-148a binding site) by a single run of allele-specific real-time PCR

Surface expression of human leukocyte antigen (HLA)-class I molecules is critical for modulating T/natural killer lymphocytes' effector functions. Among HLA molecules, HLA-C, the most recently evolved form of class I antigens, is subjected to both transcriptional and multiple post-transcriptional regulation mechanisms affecting its cell surface expression. Among the latter a region placed in the 3' untranslated region of HLA-C transcript contains the single nucleotide polymorphism (SNP) rs67384697 "G-ins/del" that has been found to be strictly associated with surface levels of HLA-C allomorphs because of the effect on the binding site of a microRNA (Hsa-miR-148a). Higher expression of HLA-C has been proved to influence HIV-1 infection via a better control of viremia and a slower disease progression. More importantly, the analysis of SNP rs67384697 "G-ins/del" combined with the evaluation of the HLA-Bw4/-Bw6 C1/C2 supratype, as well as the killer immunoglobulin-like receptor genetic asset, has proved to be pivotal in defining the status of Elite Controllers in the Caucasian population. Here we describe a new reliable and fast method of allele-specific real-time PCR to monitor the integrity/disruption of the binding site of the microRNA Hsa-miR-148a in a high-throughput format that can be easily applied to studies involving large cohorts of individuals.

T Cell Therapy Targeted on HLA-A02 Restricted HIV Antigen Epitopes: An Open Label Cellular Therapy Trial Using CD8+ T Cell

Objective: To test the safety and efficacy of a T cell therapy de novo targeting HLA-A02 restricted HIV antigen epitopes.

Design: This was a prospective open label clinical trial, which enrolled 28 HIV+ participants and 24 of them finished the trial. The study was publicly registered at Chinese Clinical Trial Registry, www.chictr.org.cn(ChiCTR-ICR-15005775).

Method: Autologous peripheral blood mononuclear cells were co-cultured with HLA-A02 restricted HIV antigen epitopes peptides to produce cell product for this therapy. The trial was divided into five time-points with the same interval period for infusion of the cell products or monitoring parameters. Symptoms, vital signs, and blood samples were collected to analyze the safety and efficacy of this therapy.

Results: Two cases of adverse effects happened during this trial in test group, which recovered without medical intervention. There was no severe adverse effect that occurred. Both symptoms and laboratory tests have no statistical significant difference between test and control group. Flowcytometry analysis showed the expression of the PD-1 and CD95 molecule on the cell surface were downregulated post-treatment in the test group.

Conclusions: This autologous HIV-antigen specific effector CD8+ T cellular therapy was safe. It might have an impact on immune suppression that can provide useful reference to future cell therapy trials.

Stability and Expression Levels of HLA-C on the Cell Membrane Modulate HIV-1 Infectivity

HLA-C expression is associated with a differential ability to control HIV-1 infection. Higher HLA-C levels may lead to better control of HIV-1 infection through both a higher efficiency of antigen presentation to cytotoxic T lymphocytes and the triggering of activating killer immunoglobulin-like receptors on NK cells, whereas lower levels may provide poor HIV-1 control and rapid progression to AIDS. We characterized the relative amounts of HLA-C heterotrimers (heavy chain/β₂ microglobulin [β₂m]/peptide) and HLA-C free heavy chains on peripheral blood mononuclear cells (PBMCs) from healthy blood donors harboring both alleles with stable or unstable binding to β₂m/peptide. We analyzed the stability of HLA-C heterotrimers of different allotypes and the infectivity of HIV-1 virions produced by PBMCs with various allotypes. We observed significant differences in HLA-C heterotrimer stability and in expression levels. We found that R5 HIV-1 virions produced by PBMCs harboring unstable HLA-C alleles were more infectious than those produced by PBMCs carrying the stable variants. We propose that HIV-1 infectivity might depend both on the amounts of HLA-C molecules and on their stability as trimeric complex. According to this model, individuals with low-expression HLA-C alleles and unstable binding to β₂m/peptide might have worse control of HIV-1 infection and an intrinsically higher capacity to support viral replication.

IMPORTANCE Following HIV-1 infection, some people advance rapidly to AIDS while others have slow disease progression. HLA-C, a molecule involved in immunity, is a key determinant of HIV-1 control. Here we reveal how HLA-C variants contribute to the modulation of viral infectivity. HLA-C is present on the cell surface in two different conformations. The immunologically active conformation is part of a complex that includes β₂ microglobulin/peptide; the other conformation is not bound to β₂ microglobulin/peptide and can associate with HIV-1, increasing its infectivity. Individuals with HLA-C variants with a predominance of immunologically active conformations would display stronger immunity to HIV-1, reduced viral infectivity and effective control of HIV-1 infection, while subjects with HLA-C variants that easily dissociate from β₂ microglobulin/peptide would have a reduced immunological response to HIV-1 and produce more infectious virions. This study provides new information that could be useful in the design of novel vaccine strategies and therapeutic approaches to HIV-1.

What Is the most Important for Elite Control: Genetic Background of Patient, Genetic Background of Partner, both or neither? Description of Complete Natural History within a Couple of MSM

Background

We describe a homosexual man who strongly controlled HIV-1 for ten years despite lack of protective genetic background.

Methods

HIV-1 DNA was measured in blood and other tissues. Cell susceptibility was evaluated with various strains. HIV-1-specific (CD4 and CD8 activation markers and immune check points) and NK cells responses were assessed; KIRs haplotypes and HLA alleles were determined.

Findings

Two HIV-1 RNA copies/mL of plasma were detected in 2009, using an ultra-sensitive assay. HIV-DNA was detected at 1.1 and 2 copies/10⁶ PBMCs in 2009 and 2015 respectively, at 1.2 copies/10⁶ cells in rectal cells in 2011. WBs showed weak reactivity with antibodies to gp160, p55 and p25 from 2007 to 2014, remaining incomplete in 2017. CD4 T cells were susceptible to various strains including HIV_KON, a primary isolate of his own CRF02_AG variant. CD8 T cells showed a strong poly-functional response against HIV-Gag, producing mainly IFN-γ; a robust capacity of antibody-dependant cell cytotoxicity (ADCC) was observed in NK cells. Case patient was group B KIR haplotype. Neutralizing antibodies were not detected. CD4 and CD8 blood T cells showed normal proportions without increased activation markers. Phylogenetic analyses identified the same CRF02_AG variant in his partner. The patient and his partner were heterozygous for the CCR5ΔD32 deletion and shared HLA-B*07, C*07 non-protective alleles.

Interpretation

This thorough description of the natural history of an individual controlling HIV-1 in various compartments for ten years despite lack of protective alleles, and of his partner, may have implications for strategies to cure HIV-1 infection.

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We described a MSM, elite controller despite pejorative genetic background.

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The patient had two HLA pejoratives alleles and no protective alleles.

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The partner was infected by the same strain.

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The genetic backgrounds of the patient and partner, and the virus could interact with each other to lead to elite control.

We considered all the evidence about elite control, HLA, ADCC and NK, using Medline/PubMed. We described a MSM, elite controller despite non-protective genetic background, explored extensively the patient: sequential WBs, RNA in plasma (ultrasensitive assay), DNA in PBMC/GALT, cell susceptibility, HIV-1 responses in PBMC/LNMC, neutralizing antibodies, CD3-CD56 + NK, ADCC, KIRs. He had one HLA pejorative and no protective alleles. The partner was infected by the same strain, his genetic background was studied. The genetic background of the exposed person, of the source, and the viral strain could interact with each other to lead to elite control.

HLA based selection of epitopes offers a potential window of opportunity for vaccine design against HIV

The pace of progression to AIDS after HIV infection varies from individual to individual. While some individuals develop AIDS quickly, others are protected from the onset of disease for more than a decade (elite controllers and long term non-progressors). The mechanisms of protection are not yet clearly understood, though various factors including host genetics, immune components and virus attenuation have been elucidated partly. The influence of HLA alleles on HIV-1 infection and disease outcome has been studied extensively. Several HLA alleles are known to be associated with resistance to infection or delayed progression to AIDS after infection. Similarly, certain HLA alleles are reported to be associated with rapid progression to disease. Since HLA alleles influence the outcome of HIV infection differentially, selection of epitopes specifically recognized by protective alleles could serve asa rational means for HIV vaccine design. In this review article, we discuss existing knowledge on HLA alleles and their association with resistance/susceptibility to HIV and its relevance to vaccine design.

Activating Killer Immunoglobulin Receptors and HLA-C: a successful combination providing HIV-1 control

Several studies demonstrated a relevant role of polymorphisms located within the HLA-B and -C loci and the Killer Immunoglobulin Receptors (KIRs) 3DL1 and 3DS1 in controlling HIV-1 replication. KIRs are regulatory receptors expressed at the surface of NK and CD8+ T-cells that specifically bind HLA-A and -B alleles belonging to the Bw4 supratype and all the -C alleles expressing the C1 or C2 supratype. We here disclose a novel signature associated with the Elite Controller but not with the long-term nonprogressor status concerning 2DS activating KIRs and HLA-C2 alleles insensitive to miRNA148a regulation. Overall, our findings support a crucial role of NK cells in the control of HIV-1 viremia.

HIV and host immunogenetics: unraveling the role of HLA-C

Host genetic factors play a major role in determining the outcome of many infections including human immunodeficiency virus (HIV). Multiple host factors have been studied till date showing their varied role in susceptibility or resistance to HIV infection. HLA-C, however, has been recently started gaining interest in researchers mind revealing its polymorphisms to have an important effect on viral load set-points, disease progression as well as transmission. In this review report, we have compiled these significant findings of HLA-C in HIV infection, in an attempt to highlight the need for further research in the area in different ethnic population to establish its role in the infection.

Genetic Markers of the Host in Persons Living with HTLV-1, HIV and HCV Infections

Human T-cell leukemia virus type 1 (HTLV-1), hepatitis C virus (HCV) and human immunodeficiency virus type 1 (HIV-1) are prevalent worldwide, and share similar means of transmission. These infections may influence each other in evolution and outcome, including cancer or immunodeficiency. Many studies have reported the influence of genetic markers on the host immune response against different persistent viral infections, such as HTLV-1 infection, pointing to the importance of the individual genetic background on their outcomes. However, despite recent advances on the knowledge of the pathogenesis of HTLV-1 infection, gaps in the understanding of the role of the individual genetic background on the progress to disease clinically manifested still remain. In this scenario, much less is known regarding the influence of genetic factors in the context of dual or triple infections or their influence on the underlying mechanisms that lead to outcomes that differ from those observed in monoinfection. This review describes the main factors involved in the virus–host balance, especially for some particular human leukocyte antigen (HLA) haplotypes, and other important genetic markers in the development of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and other persistent viruses, such as HIV and HCV.