Exposed Seronegative Individuals Research Articles

Polyfunctional natural killer cells with a low activation profile in response to Toll-like receptor 3 activation in HIV-1-exposed seronegative subjects

Natural killer (NK) cells are the main mediator of the cytotoxic response in innate immunity and may be involved in resistance to HIV-1 infection in exposed seronegative (ESN) individuals. Toll-like receptor (TLR) signalling is crucial for NK cell activation. Here, we investigated the polyfunctional NK cell response to TLR3 activation in serodiscordant couples. ESN subjects showed increased IFN-γ and CD107a expression in both NK subsets, CD56bright and CD56dim cells, in response to stimulation with a TLR3 agonist, while expression was impaired in the HIV-1-infected partners. TLR3-induced expression of IFN-γ, TNF and CD107a by polyfunctional CD56bright NK cells was more pronounced in ESN individuals than that in healthy controls. Activated NK cells, as determined by CD38 expression, were increased only in the HIV-1-infected partners, with reduced IFN-γ and CD107a expression. Moreover, CD38+ NK cells of the HIV-1-infected partners were associated with increased expression of inhibitory molecules, such as NKG2A, PD-1 and Tim-3, while NK cells from ESN subjects showed decreased NKG2A expression. Altogether, these findings indicate that NK cells of ESN individuals were highly responsive to TLR3 activation and had a polyfunctional NK cell phenotype, while the impaired TLR3 response in HIV-1-infected partners was associated with an inhibitory/exhaustion NK cell phenotype.

Molecules Involved in the Vitamin-D Pathway Correlate with Higher mRNA Expression of Anti-HIV Molecules in HIV Exposed Seronegative Individuals

Molecules Involved in the Vitamin-D Pathway Correlate with Higher mRNA Expression of Anti-HIV Molecules in HIV Exposed Seronegative Individuals

Plasma and PBMC miRNA Profile in Sexually HIV-1 Exposed Seronegative Individuals

AIDS Research and Human RetrovirusesVol. 30, No. S1 Correlates of Protection in Highly Exposed Seronegative PeoplePlasma and PBMC miRNA Profile in Sexually HIV-1 Exposed Seronegative IndividualsMara Biasin, Sara Yahyaei, Mariacristina De Luca, Irma Saulle, Federica Gnudi, Salomè Ibba, Micaela Garziano, Angela Berzi, Veronica Rainone, Daria Trabattoni, Sergio Lo Caputo, Francesco Mazzotta, and Mario ClericiMara BiasinUniversity of Milan, Biomedical and Clinical Sciences, Milan, ItalySearch for more papers by this author, Sara YahyaeiUniversity of Milan, Biomedical and Clinical Sciences, Milan, ItalySearch for more papers by this author, Mariacristina De LucaUniversity of Milan, Biomedical and Clinical Sciences, Milan, ItalySearch for more papers by this author, Irma SaulleUniversity of Milan, Biomedical and Clinical Sciences, Milan, ItalySearch for more papers by this author, Federica GnudiUniversity of Milan, Biomedical and Clinical Sciences, Milan, ItalySearch for more papers by this author, Salomè IbbaUniversity of Milan, Biomedical and Clinical Sciences, Milan, ItalySearch for more papers by this author, Micaela GarzianoUniversity of Milan, Biomedical and Clinical Sciences, Milan, ItalySearch for more papers by this author, Angela BerziUniversity of Milan, Biomedical and Clinical Sciences, Milan, ItalySearch for more papers by this author, Veronica RainoneUniversity of Milan, Biomedical and Clinical Sciences, Milan, ItalySearch for more papers by this author, Daria TrabattoniUniversity of Milan, Biomedical and Clinical Sciences, Milan, ItalySearch for more papers by this author, Sergio Lo CaputoS. Maria Annunziata Hospital, Florence, ItalySearch for more papers by this author, Francesco MazzottaS. Maria Annunziata Hospital, Florence, ItalySearch for more papers by this author, and Mario ClericiDon Gnocchi Foundation, Milan, ItalySearch for more papers by this authorPublished Online:30 Oct 2014https://doi.org/10.1089/aid.2014.5154.abstractAboutSectionsView articleView Full TextPDF/EPUB ToolsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail View article"Plasma and PBMC miRNA Profile in Sexually HIV-1 Exposed Seronegative Individuals." AIDS Research and Human Retroviruses, 30(S1), p. A83FiguresReferencesRelatedDetails Volume 30Issue S1Oct 2014 InformationCopyright 2014, Mary Ann Liebert, Inc.To cite this article:Mara Biasin, Sara Yahyaei, Mariacristina De Luca, Irma Saulle, Federica Gnudi, Salomè Ibba, Micaela Garziano, Angela Berzi, Veronica Rainone, Daria Trabattoni, Sergio Lo Caputo, Francesco Mazzotta, and Mario Clerici.Plasma and PBMC miRNA Profile in Sexually HIV-1 Exposed Seronegative Individuals.AIDS Research and Human Retroviruses.Oct 2014.A83-A83.http://doi.org/10.1089/aid.2014.5154.abstractPublished in Volume: 30 Issue S1: October 30, 2014PDF download

The High Frequency of HIV Type 1-Specific Cellular Immune Responses in Seronegative Individuals with Parenteral and/or Heterosexual HIV Type 1 Exposure

Some individuals remain HIV seronegative despite repeated unprotected exposure to the virus. Recent observations led to a concept that acquired immunity plays a role in protection or at least in altered susceptibility to HIV-1 infection in highly exposed seronegative (ESN) individuals. Our aim was to study HIV-specific cellular immune responses induced in parenterally and/or heterosexually ESN individuals. Nine seronegative injection drug users (IDUs), 10 seronegative individuals, and nine of their HIV-positive sexual and/or IDU partners from the cohort of IDUs were included in the study. The discordant couples had unprotected sex, and some of seronegative partners also had parenteral exposure. Cell-mediated responses were measured in peripheral blood mononuclear cells (PBMCs) by ex vivo interferon (IFN)-γ-ELISpot and ICS combining IFN-γ, tumor necrosis factor (TNF)-α, and interleukin (IL)-2 after stimulation with four consensus peptide pools (Nef, Gag, RT, Env, subtype A-EE). Thirteen out of 19 (68%) seronegative study subjects had strong Nef peptide pool-specific ELISpot responses, three (16%) subjects responded against the Gag peptide pool, and one subject had an RT peptide pool response. Nef peptide pool responses in ESN were as high as in seropositive subjects. The multiple HIV-specific cytokine production in both CD4(+) and CD8(+) T cells was shown for several ESN subjects. The functional profiles of the immune responses were different between seronegative and HIV-positive study groups. Whether the observed cellular responses have any protective role against HIV needs to be further investigated.

Under Representation of the Inhibitory KIR3DL1 Molecule and the KIR3DL1+/BW4+ Complex in HIV Exposed Seronegative Individuals

The activation of natural killer (NK) cells is modulated by surface molecules. We analyzed NK cells in human immunodeficiency virus (HIV)-exposed seronegative (HESN) individuals by means of molecular typing of HLA B, Cw, and killer cell immunoglobulin-like receptor (KIR) molecules. In HESN individuals, compared with HIV patients, the frequency of the inhibitory KIR3DL1 allele and of the KIR3DL1(+)/Bw4(+) inhibitory complex was reduced, whereas that of the activatory KIR3DS1(+) ligand and the activatory Bw4(+)/3DL1(-)/3DS1(+) complex was increased, resulting in a statistically significant diversion from Hardy-Weinberg equilibrium (KIR3DS1 homozygote) in HESN individuals. The reciprocal equilibrium between inhibitory and activatory NK receptors and their ligands favors NK activation in HESN individuals.

Low-Level Exposure to HIV Induces Virus-Specific T Cell Responses and Immune Activation in Exposed HIV-Seronegative Individuals

HIV-specific T cells response and T cell activation are frequently seen in exposed seronegative individuals (ESN). In this study, we report HIV-specific response and level of T cell activation in ESN partners of HIV-infected patients presenting low or undetectable levels of HIV-RNA. We evaluated 24 HIV-serodiscordant couples. ESN were classified into three categories of exposure to HIV (very low, low, and moderate-high), considering levels of HIV-RNA in their infected partner and frequency of sexual high-risk practices within the last 12 mo. HIV-specific T cell responses and activation levels in T cell subsets were evaluated by flow cytometry. We reported that 54% of ESN had detectable HIV-specific T cells response, being the highest prevalence seen in the low exposure group (64%). Several T cell subsets were significantly increased in ESN when compared with controls: CD4(+)CD38(+) (p = 0.006), CD4(+)HLA-DR(-)CD38(+) (p = 0.02), CD4(+)CD45RA(+)CD27(+)HLA-DR(-)CD38(+) (p = 0.002), CD8(+)CD45RA(+)CD27(+)CD38(-)HLA-DR(+) (p = 0.02), and CD8(+)CD45RA(+)CD27(-)CD38(+)HLA-DR(+) (p = 0.03). Activation of CD8(+) T cells was increased in ESN with detectable HIV T cell responses compared with ESN lacking these responses (p = 0.04). Taken together, these results suggest that persistent but low sexual HIV exposure is able to induce virus-specific T cells response and immune activation in a high proportion of ESN, suggesting that virus exposure may occur even in conditions of maximal viral suppression in the HIV-infected partner.

TLR Activation Pathways in HIV-1–Exposed Seronegative Individuals

TLRs trigger innate immunity that recognizes conserved motifs of invading pathogens, resulting in cellular activation and release of inflammatory factors. The influence of TLR activation on resistance to HIV-1 infection has not been investigated in HIV-1 exposed seronegative (ESN) individuals. PBMCs isolated from heterosexually ESN individuals were stimulated with agonists specific for TLR3 (poly I:C), TLR4 (LPS), TLR7 (imiquimod), and TLR7/8 (ssRNA40). We evaluated expression of factors involved in TLR signaling cascades, production of downstream effector immune mediators, and TLR-expression in CD4+ and CD14+ cells. Results were compared with those obtained in healthy controls (HCs). ESN individuals showed: 1) comparable percentages of CD14+/TLR4+ and CD4+/TLR8+ CD14+/TLR8+ cells; 2) higher responsiveness to poly I:C, LPS, imiquimod, and ssRNA40 stimulation, associated with significantly increased production of IL-1beta, IL-6, TNF-alpha, and CCL3; 3) augmented expression of mRNA specific for other targets (CCL2, CSF3, CSF2, IL-1alpha, IL-8, IL-10, IL-12, cyclooxygenase 2) demonstrated by broader TLRs pathway expression analyses; and 4) increased MyD88/MyD88s(short) ratio, mainly following TLR7/8 stimulation. We also compared TLR-agonist-stimulated cytokine/chemokine production in CD14+ PBMCs and observed decreased IFN-beta production in ESN individuals compared with HCs upon TLR7/8-agonist stimulation. These data suggest that TLR stimulation in ESN individuals results in a more robust release of immunologic factors that can influence the induction of stronger adaptive antiviral immune responses and might represent a virus-exposure-induced innate immune protective phenotype against HIV-1.

Distinct patterns of peripheral HIV-1-specific interferon- gamma responses in exposed HIV-1-seronegative individuals.

It is unclear how human immunodeficiency virus (HIV) type 1-specific immune responses in exposed seronegative (ESN) individuals differ from those in HIV-1-infected subjects. By use of overlapping peptides spanning Gag, Tat, Nef, Vif, Vpr, and Vpu, peripheral blood mononuclear cells from ESN individuals, their seropositive (SP) partners, and unexposed seronegative control subjects were screened for interferon- gamma production. Responses were more frequent (95.7% vs. 20%), of a higher magnitude (9-fold), and of wider breadth (median number of peptides recognized, 18 vs. 2.5) in SP than in ESN individuals. Peptides recognized by ESN individuals were less frequently recognized by their SP partners. SP subjects infrequently recognized peptides from Vif, and such responses were subdominant; among ESN individuals, this HIV-1 protein was most frequently recognized. Immunodominant peptides recognized by SP subjects tended to be from relatively conserved regions, whereas peptides recognized by ESN individuals were associated with slow disease progression.

Persistence of extraordinarily low levels of genetically homogeneous human immunodeficiency virus type 1 in exposed seronegative individuals.

Some individuals remain inexplicably seronegative and lack evidence for human immunodeficiency virus type 1 (HIV-1) infection by conventional serologic or virologic testing despite repeated high-risk virus exposures. Here, we examined 10 exposed seronegative (ES) individuals exhibiting HIV-1-specific cytotoxicity for the presence of HIV-1. We discovered HIV-1 DNA in resting CD4(+) T cells (mean, 0.05 +/- 0.01 copies per million cells) at multiple visits spanning 69 to 130 weeks in two ES individuals at levels that were on average 10(4)- to 10(6)-fold lower than those of other HIV-1-infected populations reported. Sequences of HIV-1 envelope and gag genes remained markedly homogeneous, indicating little to undetectable virus replication. These results provide the evidence for HIV-1 infection in ES individuals below the detection limit of standard assays, suggesting that extraordinary control of infection can occur. The two HIV-infected ES individuals remained healthy and were not superinfected with other HIV-1 strains despite continued high-risk sexual exposures to multiple HIV-infected partners. Understanding the mechanisms that confer diminished replicative capacity of HIV-1 in these hosts is paramount to developing strategies for protection against and control of HIV-1 infection.