Devi SenGupta

A comparative trial of granulocyte‐colony‐stimulating factor and dexamethasone, separately and in combination, for the mobilization of neutrophils in the peripheral blood of normal volunteers

BACKGROUND: The clinical utility of polymorphonuclear neutrophil (PMN) transfusion therapy has been compromised, in part, by the inability to obtain sufficient quantities of functional neutrophils from donors. To define the optimal conditions for mobilization of PMNs in granulocyte donors, the effects of granulocyte‐colony‐stimulating factor (G‐CSF) and dexamethasone, separately and in combination, on PMN counts in normal volunteers were compared. STUDY DESIGN AND METHODS: Five normal subjects were randomly assigned to each of the following single‐dose regimens in 5 consecutive weeks: 1) G‐CSF, 300 micrograms given subcutaneously; 2) G‐CSF, 600 micrograms subcutaneously: 3) dexamethasone, 8 mg given orally; 4) G‐CSF, 300 micrograms subcutaneously, plus dexamethasone, 8 mg orally; and 5) G‐CSF, 600 micrograms subcutaneously, plus dexamethasone 8 mg orally. Venous blood was collected at 0, 6, 12, and 24 hours after drug administration for the determination of absolute neutrophil counts (ANCs). RESULTS: Maximal ANC was achieved at 12 hours after each regimen, except dexamethasone alone (maximum, 24 hours). Dexamethasone significantly increased the maximal ANC induced by either dose of G‐CSF alone (p < 0.05). The greatest mobilization of PMNs occurred after the administration of G‐CSF (600 micrograms) and dexamethasone (8 mg); the ANC increased from a mean baseline value of 3,594 per microL to 43,017 per microL at 12 hours. All of the drug regimens were well tolerated. CONCLUSION: Dexamethasone significantly increases the level of neutrophilia induced in normal subjects by G‐CSF. The combination of dexamethasone and G‐CSF (at the dosages used in this study) is a convenient, well‐tolerated regimen for the mobilization of PMNs in the peripheral blood of granulocyte donors. Moreover, the optimal quantitative yield of PMNs is likely to be achieved by leukapheresis 12 hours after drug administration.

Heat Shock Protein-Mediated Cross-Presentation of Exogenous HIV Antigen on HLA Class I and Class II

Strong CD4+ and CD8+ T cell responses are considered important immune components for controlling HIV infection, and their priming may be central to an effective HIV vaccine. We describe in this study an approach by which multiple CD4+ and CD8+ T cell epitopes are processed and presented from an exogenously added HIV-1 Gag-p24 peptide of 32 aa complexed to heat shock protein (HSP) gp96. CD8+ T cell recognition of the HSP/peptide complex, but not the peptide alone, was inhibited by brefeldin A, suggesting an endoplasmic reticulum-dependent pathway. This is the first report to describe efficient processing and simultaneous presentation of overlapping class I- and class II-restricted epitopes from the same extracellularly added precursor peptide complexed to HSP. Given previous reports of the strong immunogenicity of HSP/peptide complexes, the present data suggest that HSP-complexed peptides containing multiple MHC class I- and class II-restricted epitopes represent potential vaccine candidates for HIV and other viral infections suitable to induce effective CTL memory by simultaneously providing CD4 T cell help.

HERV-K–specific T cells eliminate diverse HIV-1/2 and SIV primary isolates

The genetic diversity of HIV-1 represents a major challenge in vaccine development. In this study, we establish a rationale for eliminating HIV-1-infected cells by targeting cellular immune responses against stable human endogenous retroviral (HERV) antigens. HERV DNA sequences in the human genome represent the remnants of ancient infectious retroviruses. We show that the infection of CD4+ T cells with HIV-1 resulted in transcription of the HML-2 lineage of HERV type K [HERV-K(HML-2)] and the expression of Gag and Env proteins. HERV-K(HML-2)-specific CD8+ T cells obtained from HIV-1-infected human subjects responded to HIV-1-infected cells in a Vif-dependent manner in vitro. Consistent with the proposed mode of action, a HERV-K(HML-2)-specific CD8+ T cell clone exhibited comprehensive elimination of cells infected with a panel of globally diverse HIV-1, HIV-2, and SIV isolates in vitro. We identified a second T cell response that exhibited cross-reactivity between homologous HIV-1-Pol and HERV-K(HML-2)-Pol determinants, raising the possibility that homology between HIV-1 and HERVs plays a role in shaping, and perhaps enhancing, the T cell response to HIV-1. This justifies the consideration of HERV-K(HML-2)-specific and cross-reactive T cell responses in the natural control of HIV-1 infection and for exploring HERV-K(HML-2)-targeted HIV-1 vaccines and immunotherapeutics.

Strong Human Endogenous Retrovirus-Specific T Cell Responses Are Associated with Control of HIV-1 in Chronic Infection

ABSTRACT Eight percent of the human genome is composed of human endogenous retroviruses (HERVs), which are thought to be inactive remnants of ancient infections. Previously, we showed that individuals with early HIV-1 infection have stronger anti-HERV T cell responses than uninfected controls. In this study, we investigated whether these responses persist in chronic HIV-1 infection and whether they have a role in the control of HIV-1. Peripheral blood mononuclear cells (PBMCs) from 88 subjects diagnosed with HIV-1 infection for at least 1 year (median duration of diagnosis, 13 years) were tested for responses against HERV peptides in gamma interferon (IFN-γ) enzyme immunospot (ELISPOT) assays. Individuals who control HIV-1 viremia without highly active antiretroviral therapy (HAART) had stronger and broader HERV-specific T cell responses than HAART-suppressed patients, virologic noncontrollers, immunologic progressors, and uninfected controls (P < 0.05 for each pairwise comparison). In addition, the magnitude of the anti-HERV T cell response was inversely correlated with HIV-1 viral load (r 2 = 0.197, P = 0.0002) and associated with higher CD4+ T cell counts (r 2 = 0.072, P = 0.027) in untreated patients. Flow cytometric analyses of an HLA-B51-restricted CD8+ HERV response in one HIV-1-infected individual revealed a less activated and more differentiated phenotype than that stimulated by a homologous HIV-1 peptide. HLA-B51 tetramer dual staining within this individual confirmed two different T cell populations corresponding to these HERV and HIV-1 epitopes, ruling out cross-reactivity. These findings suggest a possible role for anti-HERV immunity in the control of chronic HIV-1 infection and provide support for a larger effort to design an HIV-1 vaccine that targets conserved antigens such as HERV.

Identification of Human Endogenous Retrovirus-Specific T Cell Responses in Vertically HIV-1-Infected Subjects

ABSTRACT Human endogenous retrovirus (HERV)-specific T cell responses in HIV-1-infected adults have been reported. Whether HERV-specific immunity exists in vertically HIV-1-infected children is unknown. We performed a cross-sectional analysis of HERV-specific T cell responses in 42 vertically HIV-1-infected children. HERV (-H, -K, and -L family)-specific T cell responses were identified in 26 of 42 subjects, with the greatest magnitude observed for the responses to HERV-L. These HERV-specific T cell responses were inversely correlated with the HIV-1 plasma viral load and positively correlated with CD4+ T cell counts. These data indicate that HERV-specific T cells may participate in controlling HIV-1 replication and that certain highly conserved HERV-derived proteins may serve as promising therapeutic vaccine targets in HIV-1-infected children.

Coformulated bictegravir, emtricitabine, and tenofovir alafenamide versus dolutegravir with emtricitabine and tenofovir alafenamide, for initial treatment of HIV-1 infection (GS-US-380–1490): a randomised, double-blind, multicentre, phase 3, non-inferiority trial

BACKGROUND Integrase strand transfer inhibitors (INSTIs) coadministered with two nucleoside or nucleotide reverse transcriptase inhibitors (NRTIs) are recommended as first-line treatment for HIV, and coformulated fixed-dose combinations are preferred to facilitate adherence. We report 48-week results from a study comparing initial HIV-1 treatment with bictegravir-a novel INSTI with a high in-vitro barrier to resistance and low potential as a perpetrator or victim of clinically relevant drug interactions-coformulated with the NRTI combination emtricitabine and tenofovir alafenamide as a fixed-dose combination to dolutegravir administered with coformulated emtricitabine and tenofovir alafenamide. METHODS In this randomised, double-blind, multicentre, placebo-controlled, non-inferiority trial, HIV-infected adults were screened and enrolled at 126 outpatient centres in 10 countries in Australia, Europe, Latin America, and North America. Participants were previously untreated adults (HIV-1 RNA ≥500 copies per mL) with estimated glomerular filtration rate of at least 30 mL/min. Chronic hepatitis B virus or hepatitis C co-infection was allowed. We randomly assigned participants (1:1) to receive oral fixed-dose combination bictegravir 50 mg, emtricitabine 200 mg, and tenofovir alafenamide 25 mg or dolutegravir 50 mg with coformulated emtricitabine 200 mg and tenofovir alafenamide 25 mg, with matching placebo, once a day for 144 weeks. Investigators, participants, study staff, and those assessing outcomes were masked to treatment group. All participants who received at least one dose of study drug were included in primary efficacy and safety analyses. The primary endpoint was the proportion of participants with plasma HIV-1 RNA of less than 50 copies per mL at week 48 (US Food and Drug Administration snapshot algorithm), with a prespecified non-inferiority margin of -12%. This study is registered with ClinicalTrials.gov, number NCT02607956. FINDINGS Between Nov 11, 2015, and July 15, 2016, 742 participants were screened for eligibility, of whom 657 were randomly assigned to treatment (327 with bictegravir, emtricitabine, and tenofovir alafenamide fixed-dose combination [bictegravir group] and 330 with dolutegravir plus emtricitabine and tenofovir alafenamide [dolutegravir group]). 320 participants who received the bictegravir regimen and 325 participants who received the dolutegravir regimen were included in the primary efficacy analyses. At week 48, HIV-1 RNA <50 copies per mL was achieved in 286 (89%) of 320 participants in the bictegravir group and 302 (93%) of 325 in the dolutegravir group (difference -3·5%, 95·002% CI -7·9 to 1·0, p=0·12), showing non-inferiority of the bictegravir regimen to the dolutegravir regimen. No treatment-emergent resistance to any study drug was observed. Incidence and severity of adverse events were similar between groups, and few participants discontinued treatment due to adverse events (5 [2%] of 320 in the bictegravir group and 1 [<1%] 325 in the dolutegravir group). Study drug-related adverse events were less common in the bictegravir group than in the dolutegravir group (57 [18%] of 320 vs 83 [26%] of 325, p=0·022). INTERPRETATION At 48 weeks, virological suppression with the bictegravir regimen was achieved and was non-inferior to the dolutegravir regimen in previously untreated adults. There was no emergent resistance to either regimen. The fixed-dose combination of bictegravir, emtricitabine, and tenofovir alafenamide was safe and well tolerated compared with the dolutegravir regimen. FUNDING Gilead Sciences Inc.

Trans-activation, post-transcriptional maturation, and induction of antibodies to HERV-K (HML-2) envelope transmembrane protein in HIV-1 infection

BackgroundHuman Endogenous Retroviruses (HERVs) comprise about 8% of the human genome and have lost their ability to replicate or to produce infectious particles after having accumulated mutations over time. We assessed the kinetics of expression of HERV-K (HML-2) Envelope mRNA transcript and surface unit (SU) and transmembrane (TM) subunit proteins during HIV-1 infection. We also mapped the specificity of the humoral response to HERV-K (HML-2) Envelope protein in HIV-1 infected subjects at different stages of disease, and correlated the response with plasma viral load.ResultsWe found that HIV-1 modified HERV-K (HML-2) Env mRNA expression, resulting in the expression of a fully N-glycosylated HERV-K (HML-2) envelope protein on the cell surface. Serological mapping of HERV-K (HML-2) envelope protein linear epitopes revealed two major immunogenic domains, one on SU and another on the ectodomain of TM. The titers of HERV-K (HML-2) TM antibodies were dramatically increased in HIV-1 infected subjects (p < 0.0001). HIV-1 infected adults who control HIV-1 in the absence of therapy (“elite” controllers) had a higher titer response against TM compared to antiretroviral-treated adults (p < 0.0001) and uninfected adults (p < 0.0001).ConclusionsThese data collectively suggest that HIV-1 infection induces fully glycosylated HERV-K (HML-2) envelope TM protein to which antibodies are induced. These anti-HERV-K (HML-2) TM antibodies are a potential marker of HIV-1 infection, and are at higher titer in elite controllers. HERV-K (HML-2) envelope TM protein may be a new therapeutic target in HIV-1 infection.

The CD8+ Memory Stem T Cell (TSCM) Subset Is Associated with Improved Prognosis in Chronic HIV-1 Infection

ABSTRACT Memory stem T cells (TSCM) constitute a long-lived, self-renewing lymphocyte population essential for the maintenance of functional immunity. The hallmarks of HIV-1 pathogenesis are CD4+ T cell depletion and abnormal cellular activation. We investigated the impact of HIV-1 infection on the TSCM compartment, as well as any protective role these cells may have in disease progression, by characterizing this subset in a cohort of 113 subjects with various degrees of viral control on and off highly active antiretroviral therapy (HAART). We observed that the frequency of CD8+ TSCM was decreased in all individuals with chronic, untreated HIV-1 infection and that HAART had a restorative effect on this subset. In contrast, natural controllers of HIV-1 had the highest absolute number of CD4+ TSCM cells among all of the infected groups. The frequency of CD4+ TSCM predicted higher CD8+ TSCM frequencies, consistent with a role for the CD4+ subset in helping to maintain CD8+ memory T cells. In addition, TSCM appeared to be progenitors for effector T cells (TEM), as these two compartments were inversely correlated. Increased frequencies of CD8+ TSCM predicted lower viral loads, higher CD4+ counts, and less CD8+ T cell activation. Finally, we found that TSCM express the mucosal homing integrin α4β7 and can be identified in gut-associated lymphoid tissue (GALT). The frequency of mucosal CD4+ TSCM was inversely correlated with that in the blood, potentially reflecting the ability of these self-renewing cells to migrate to a crucial site of ongoing viral replication and CD4+ T cell depletion. IMPORTANCE HIV-1 infection leads to profound impairment of the immune system. TSCM constitute a recently identified lymphocyte subset with stem cell-like qualities, including the ability to generate other memory T cell subtypes, and are therefore likely to play an important role in controlling viral infection. We investigated the relationship between the size of the CD8+ TSCM compartment and HIV-1 disease progression in a cohort of chronically infected individuals. Our results suggest that HAART restores a normal frequency of CD8+ TSCM and that the natural preservation of this subset in the setting of untreated HIV-1 infection is associated with improved viral control and immunity. Therefore, the CD8+ TSCM population may represent a correlate of protection in chronic HIV-1 infection that is directly relevant to the design of T cell-based vaccines, adoptive immunotherapy approaches, or the pharmacologic induction of TSCM.

Bacteroides are associated with GALT iNKT cell function and reduction of microbial translocation in HIV-1 infection

Invariant natural killer T (iNKT) cells are innate-like T cells that respond to lipid antigens presented by CD1d. These immunoregulatory cells have the capacity for rapid cytokine release after antigen recognition and are essential for the activation of multiple arms of the immune response. HIV-1 infection is associated with iNKT cell depletion in the peripheral blood; however, their role in the gastrointestinal-associated lymphoid tissue (GALT) is less well studied. Our results show that iNKT cells are found at a higher frequency in GALT compared with blood, particularly in HIV-1 elite controllers. The capacity of iNKT cells to produce interleukin-4 (IL-4) and IL-10 in the GALT was associated with less immune activation and lower markers of microbial translocation, whereas regulatory T cell frequency showed positive associations with immune activation. We hypothesized that the composition of the microbiota would influence iNKT cell frequency and function. We found positive associations between the abundance of several Bacteroides species and iNKT cell frequency and their capacity to produce IL-4 in the GALT but not in the blood. Overall, our results are consistent with the hypothesis that GALT iNKT cells, influenced by certain bacterial species, may have a key role in regulating immune activation in HIV-1 infection.

Human endogenous retrovirus expression is inversely associated with chronic immune activation in HIV-1 infection

Human endogenous retroviruses (HERV) are remnants of ancestral retroviral infections integrated into the germ line, and constitute approximately 8% of the genome. Several autoimmune disorders, malignancies, and infectious diseases such as HIV-1 are associated with higher HERV expression. The degree to which HERV expression in vivo results in persistent inflammation is not known. We studied the association of immune activation and HERV-K expression in 20 subjects with chronic, untreated progressive HIV-1 infection and 10 HIV-1 negative controls. The mean HERV-K gag and env RNA expression level in the HIV-1 infected cohort was higher than in the control group (p = 0.0003), and was negatively correlated with the frequency of activated CD38+HLA-DR+CD4+ T cells (Rho = −0.61; p = 0.01) and activated CD38+HLA-DR+CD8+ T cells (Rho  = −0.51; p = 0.03). Although HIV-infected persons had higher levels of HERV-K RNA expression (as expected), the level of RNA expression was negatively associated with level of T cell activation. The mechanism for this unexpected association remains to be defined.