Strategies to reduce the human immunodeficiency virus (HIV) reservoir are urgently required. The antibody-dependent cellular cytotoxicity (ADCC)-mediating anti-HIV antibodies have shown an ...association with HIV control. We assessed if such antibodies can be generated
and whether the generated antibodies can facilitate the reduction of reactivated HIV reservoir. We isolated HIV-1-gp140-specific memory B cells from HIV-1-infected long-term non-progressors (LTNPs) with or without plasma ADCC and cultured them to generate anti-HIV antibodies. The ability of the generated antibodies to mediate ADCC and facilitate NK cell-mediated lysis of reactivated HIV reservoir was assessed by the rapid fluorometric antibody-dependent cellular cytotoxicity assay and a flow-based novel latency reduction assay, respectively. All LTNPs showed the presence of gp140-specific memory B cells median: 0.79% (0.54%-1.225%), which were successfully differentiated into plasma cells median 72.0% (68.7-82.2%) in an
culture and secreted antibodies median OD: 0.253 (0.205-0.274). The HIV-gp140-specific antibodies were generated from 11/13 LTNPs irrespective of their plasma ADCC status. The generated antibodies from LTNPs with plasma ADCC showed higher ADCC potency (median: 37.6%, IQR: 32.95%-51%) and higher reduction in reactivated HIV reservoir (median: 62.5%, IQR: 58.71%-64.92%) as compared with the antibodies generated from LTNPs without plasma ADCC (ADCC: median: 8.85%, IQR: 8%-9.7%; and % p24 reduction median: 13.84, IQR: 9.863%-17.81%). The potency of these antibodies to reduce latent reservoir was two-fold higher than the respective plasma ADCC. The study showed that the potent ADCC-mediating antibodies could be generated from memory B cells of the LTNPs with plasma ADCC activity. These antibodies also showed potent ability to facilitate NK cell-mediated lysis of reactivated HIV reservoirs. It also indicated that memory B cells from individuals with plasma ADCC activity should be preferentially used for such antibody generation. The important role of these antibodies in the reduction of latent reservoirs needs to be further evaluated as a useful strategy to obtain a functional cure for HIV infection.
Persistence of HIV reservoir even in suppressive ART is the key obstacle in HIV-1 cure. We evaluated the ability of HIV-1 C Env to reactivate the latently infected resting memory CD4 cells and the ...ability of polyclonal HIV antibodies mediating ADCC to lyse the reactivated targets.
HIV-1 antibodies from 25 HIV infected individuals (14 ADCC responders and 11 non-responders) were tested against the Env-C reactivated primary cells; CD4+ and CD4+CD45RO+ memory T cells in the presence of autologous or heterologous effector cells using multicolor flow cytometry. The frequencies of p24+ve target cells were measured to determine the reactivation and antibody mediated lysis.
Increase in the frequency of p24 expressing cells (P < 0.01 in all cases) after Env-C stimulation of target cells indicated reactivation. When these reactivated targets were mixed with effector cells and HIV-1 antibodies, the frequencies of p24 expressing targets were decreased significantly when the ADCC mediating antibodies (P < 0.01 in all cases) were added but not when the antibodies from ADCC non-responders or HIV negative individuals were added. In parallel, the NK cell activation was also increased only when ADCC mediating antibodies were added.
The study showed that the HIV-1 Env could act as latency reversal agent (LRA), and only ADCC mediating antibodies could lyse the reactivated HIV reservoirs. The short stimulation cycle used in this study could be useful in testing LRAs as well as immune mediated lysis of reactivated reservoirs. The observations have further implication in designing antibody mediated immunotherapy for eradication of latent HIV reservoir.
TGF-β has been shown to play a differential role in either restricting or aiding HIV infection in different cell types, however its role in the cervical cells is hitherto undefined. Among females, ...more than 80% of infections occur through heterosexual contact where cervicovaginal mucosa plays a critical role, however the early events during the establishment of infection at female genital mucosa are poorly understood. We earlier showed that increased TGF-β level has been associated with cervical viral shedding in the HIV infected women, however a causal relationship could not be examined. Therefore, here we first established an in vitro cell-associated model of HIV infection in the cervical epithelial cells (ME-180) and demonstrated that TGF-β plays an important role as a negative regulator of HIV release in the infected cervical epithelial cells. Inhibition of miR-155 upregulated TGF-β signaling and mRNA expression of host restriction factors such as
,
and
, while decreased the HIV release in ME-180 cells. To conclude, this is the first study to decipher the complex interplay between TGF-β, miR-155 and HIV release in the cervical epithelial cells. Collectively, our data suggest the plausible role of TGF-β in promoting HIV latency in cervical epithelial cells which needs further investigations.
OBJECTIVE:The HIV-1-specific antibodies are being considered for prevention and therapy in HIV infection. For effective antibody response, presence of functionally competent memory B cells (MEBs) is ...important; however, HIV-infection is known to alter the B-cell functionality. Very limited data are available on the HIV-specific memory B-cell population in HIV-infected Indian population.
METHODS:In this study, the frequencies of HIV-gp140-specific MEBs were measured in individuals with nonprogressive long-term-nonprogressors (LTNPs), N = 20 and progressive (N = 19) HIV infection using multicolor flow cytometry. The activation and functional status of these MEBs were assessed as frequencies and mean fluorescence intensity (MFI) of the CD38 and CD40 expression, respectively.
RESULTS:The percentages of gp140 + MEBs were higher in LTNPs than seen in progressors (P = 0.0475) and associated with higher CD4 cell count (P = 0.0312, r = 0.2833). As compared with the progressors, LTNPs also showed higher functional (CD40+) gp140 + MEBs both frequencies (P < 0.0001) and CD40 MFI (P = 0.0222), whereas the frequencies (<0.0001) and the MFI (P = 0.0047) of CD38 expression was significantly lower. Higher CD4 cell counts and lower plasma viral load values were associated with higher frequencies of CD40+ gp140 + MEBs (P < 0.0001, r = 0.4962) (P = 0.0036, r = −0.4202) and lower frequencies (P = 0.0008, r = −0.4231) and CD38 expression (MFI) (P = 0.004, r = −0.3719) (P = 0.0066, r = 0.4033).
CONCLUSION:Our study suggests that LTNPs have functional HIV-specific memory B-cell compartment with reduced activation that may lead to effective HIV-specific humoral immune responses contributing to their nondisease progression status. These findings would help in better understanding of the characteristics of the HIV-specific memory B-cell population in nonprogressive HIV infection.
Hepatitis C virus (HCV) infection is a major contributor to morbidity and mortality worldwide. Early detection and curative treatment of HCV can reduce the risk of liver-related mortality and serve ...to prevent transmission of new infections. India is estimated to have about six million HCV infected individuals, most of whom are unaware of their infection status. Rapid diagnostic test kits (RDTs) could help identify HCV infected persons more expeditiously and thus availability of high performing, quality-assured RDTs is essential to scale-up HCV screening efforts. The present study was thus undertaken to evaluate the performance characteristics of five anti-HCV RDTs.
Five anti-HCV RDTs (Alere Truline, Flaviscreen, Advanced Quality, SD Bioline and OraQuick) were evaluated using two panels of known anti-HCV positive and negative samples; one characterized from Indian patient samples (n = 360) and other obtained from the US Centers for Disease Control and Prevention (CDC), Atlanta (n = 100). Sensitivity, specificity, inter-observer agreement, test validity and operational characteristics of RDTs were assessed.
The combined sensitivities across both panels for Alere Truline, Flaviscreen, Advanced Quality, SD Bioline and OraQuick RDTs were 99.4% (95%CI-96.6%-99.9%), 86.2% (95%CI-79.8%-91.1%), 96.2% (95%CI-91.9%-98.6%), 99.4% (95%CI-96.6%-99.9%) and 99.4% (95%CI-96.6%-99.9%) respectively. The overall specificities across both panels for all RDTs were 99.7%. The inter-observer agreement was 100% for Alere Truline, SD Bioline and OraQuick, while it was 99.5% and 98.6% with Advanced Quality and Flavicheck respectively. Discordant results were significantly associated with human immunodeficiency virus (HIV) positivity for both Advanced Quality and Flavicheck (p<0.001).
The present evaluation demonstrated that Alere Truline, SD Bioline and OraQuick RDTs had sensitivity and specificity in accordance with the acceptance criteria of the Drug Controller General, India, the national regulatory authority, had excellent inter-observer agreement and superior operational characteristics. Our findings suggest that certain HCV RDTs perform well and can be a useful tool in screening of HCV infections expeditiously.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
CD1d restricted invariant natural killer T (iNKT) cells are important in the activation and regulation of immune responses. Limited information is available regarding the functional role of iNKT ...cells in the human immunodeficiency virus (HIV) disease progression.
α-GalCer stimulated iNKT cells were characterized for their functionality in terms of cytokine production (IFN-γ, TNF-α, IL-2, IL-4, and IL-21) and CD107a expression in HIV-1 infected 23 long-term non progressors (LTNPs), 28 progressors, 18 patients before and after suppressive anti-retroviral treatment (ART) along with 25 HIV-1 negative subjects using multicolor flow cytometry.
The functional profile of α-GalCer stimulated iNKT cells was similar in LTNPs and healthy controls. The number of LTNPs showing functional response in terms of secretion of cytokines (IFN-γ/IL2/TNF-α) and CD107a expression was significantly higher than seen in the progressors. The cytokine secretion by the stimulated iNKT cells was predominantly Th1 type. The frequencies of iNKT cells showing secretion of IFN-γ or IL2 or TNF-α or expression of CD107a were higher in LTNPs (
< 0.05 for all) and also significantly associated with lower plasma viral load (
value ranged from 0.04 to 0.003) and higher CD4 count (
value ranged from 0.02 to <0.0001). The functional profile of the iNKT cells before and after ART did not differ significantly indicating absence of restoration of iNKT cells functionality after suppressive ART. The IL-4 and IL-21 secreting iNKT cells were rare in all study populations.
The presence of functional iNKT cells secreting number of cytokines in non-progressive HIV infection could be one of the multiple factors required to achieve HIV control and hence have relevance in understanding the immunity in HIV infection. The failure of restoration of the iNKT functionality after ART should be potential area of future research.
Interferon-α (IFN-α) plays a vital role in combating viral infections especially in the early control after infection. However, the HIV infection has shown substantial level of suppression of IFN-α ...secretion during initial phase of infection. The reasons behind this impairment are still obscure. As plasmacytoid dendritic cells (pDCs) are the major producers of this cytokine, the mechanisms of HIV-1-mediated suppression of IFN-α production by pDCs using the primary pDCs were explored. The nuclear translocation of the interferon regulatory factor (IRF)-7, a transcription factor for IFN-α genes, is essential for the initiation of IFN-α production in pDCs. The HIV-1-exposed pDCs did not show the translocation of IRF-7 into the nucleus in our experiments. Furthermore, it was also observed that HIV-1 inhibited AKT phosphorylation of PI3K/akt pathway in pDCs, an important step for IRF-7 translocation to nucleus. HIV-1-induced inhibition of AKT phosphorylation and IRF-7 translocation was evident even in the presence of Toll-like receptor-7 agonist stimulation and correlated with IFN-α suppression. The findings suggest that HIV-1 may alter AKT phosphorylation to inhibit the translocation of IRF-7 into pDC nucleus, leading to IFN-α suppression, and this may be the reason for IFN-α abrogation observed in recently infected HIV patients. Understanding of interactions between HIV-1 and signaling pathways leading to IFN-α secretion may provide targets for immune intervention.
ABSTRACT
Mechanisms involved in survival of productively‐infected memory CD4+cells after initial antigenic stimulation and their subsequent reversion to the resting state are critical for the ...development of a predominant replication‐competent HIV reservoir. These mechanisms may also counter their elimination after HIV reactivation through latency‐reversing agents (LRA). Thus, their evaluation is critical when using an appropriate HIV latency model that recapitulates the predominant replication‐competent HIV reservoir to develop strategies for HIV eradication. The model for evaluating the possible survival mechanisms after T cell receptor (TCR) stimulation was developed by infecting memory CD4+cells with an HIV‐1C primary isolate and cytokine secretion and gene expression patterns determined. Infected cells showed compromised functionality as evident from 6.8‐fold lower secretion of IL‐2 than from uninfected control cells. After TCR stimulation, the infected cells showed significantly higher fold increases in CD27 and CCR5 and smaller increases in CD5 mRNA over baseline values. Because CD27 expression may influence telomerase activity through AKT phosphorylation, CD27, human telomerase reverse transcriptase (hTERT) and pAKT expression in productively‐infected cells from HIV‐infected patients was evaluated by flow cytometry. HIV harbored in memory CD4+ cells was reactivated by HIV‐1 envelope peptides, which have been shown to act as effective LRA. P24+CD4+cell showed significantly higher expression of CD27, hTERT and pAKT than P24−CD4+cells. These findings indicate compromised functionality of HIV‐infected cells after TCR stimulation, which may interfere with their elimination by the immune system. They also indicate that pAKT and hTERT induction are possible survival mechanisms of productively‐infected CD4+cells.
HIV infection predisposes latent tuberculosis-infected (LTBI) subjects to active TB. This study is designed to determine whether HIV infection of LTBI subjects compromises the balanced Mycobacterium ...tuberculosis (Mtb)-specific T helper 17 (Th17) response of recognized importance in anti-TB immunity. Comparative analysis of Mtb- and cytomegalovirus (CMV)-specific CD4+ T cell responses demonstrates a marked dampening of the Mtb-specific CD4+ T cell effectors and polyfunctional cells while preserving CMV-specific response. Additionally, HIV skews the Mtb-specific Th17 response in chronic HIV-infected LTBI progressors, but not long-term non-progressors (LTNPs), with preservation of pro-inflammatory interferon (IFN)-γ+/interleukin-17+ (IL-17+) and significant loss of anti-inflammatory IL-10+/IL-17+ effectors that is restored by anti-retroviral therapy (ART). HIV-driven impairment of Mtb-specific response cannot be attributed to preferential infection as cell-associated HIV DNA and HIV RNA reveal equivalent viral burden in CD4+ T cells from different antigen specificities. We therefore propose that beyond HIV-induced loss of Mtb-specific CD4+ T cells, the associated dysregulation of Mtb-specific T cell homeostasis can potentially enhance the onset of TB in LTBI subjects.
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•Chronic HIV infection selectively impairs Mtb-specific effector cytokine responses•Chronic HIV infection augments Mtb-specific pro-inflammatory Th17 responses•HIV-induced changes in Mtb-specific cells are independent of viral load and MIP-1β•ART/ATT restore anti-inflammatory and dampen pro-inflammatory Th17 responses
This study provides insight on how HIV may drive tuberculosis (TB). Rakshit et al. demonstrate that HIV infection of latent TB subjects profoundly alters specific immune subsets implicated in anti-TB immunity, which is independent of cellular viral burden or secretion of antiviral chemokines.
Abstract
Due to waning immunity following primary immunization with COVID-19 vaccines, booster doses may be required. The present study assessed a heterologous booster of SII-NVX-CoV2373 (spike ...protein vaccine) in adults primed with viral vector and inactivated vaccines. In this Phase 3, observer-blind, randomized, active controlled study, a total of 372 adults primed with two doses of ChAdOx1 nCoV-19 (n = 186) or BBV152 (n = 186) at least six months ago, were randomized to receive a booster of SII-NVX-CoV2373 or control vaccine (homologous booster of ChAdOx1 nCoV-19 or BBV152). Anti-S IgG and neutralizing antibodies (nAbs) were assessed at days 1, 29, and 181. Non-inferiority (NI) of SII-NVX-CoV2373 to the control vaccine was assessed based on the ratio of geometric mean ELISA units (GMEU) of anti-S IgG and geometric mean titers (GMT) of nAbs (NI margin > 0.67) as well as seroresponse (≥ 2 fold-rise in titers) (NI margin −10%) at day 29. Safety was assessed throughout the study period. In both the ChAdOx1 nCoV-19 prime and BBV152 prime cohorts, 186 participants each received the study vaccines. In the ChAdOx1 nCoV-19 prime cohort, the GMEU ratio was 2.05 (95% CI 1.73, 2.43) and the GMT ratio was 1.89 (95% CI 1.55, 2.32) whereas the difference in the proportion of seroresponse was 49.32% (95% CI 36.49, 60.45) for anti-S IgG and 15% (95% CI 5.65, 25.05) for nAbs on day 29. In the BBV152 prime cohort, the GMEU ratio was 5.12 (95% CI 4.20, 6.24) and the GMT ratio was 4.80 (95% CI 3.76, 6.12) whereas the difference in the proportion of seroresponse was 74.08% (95% CI 63.24, 82.17) for anti-S IgG and 24.71% (95% CI 16.26, 34.62) for nAbs on day 29. The non-inferiority of SII-NVX-CoV2373 booster to the control vaccine for each prime cohort was met. SII-NVX-CoV2373 booster showed significantly higher immune responses than BBV152 homologous booster. On day 181, seroresponse rates were ≥ 70% in all the groups for both nAbs and anti-S IgG. Solicited adverse events reported were transient and mostly mild in severity in all the groups. No causally related SAE was reported. SII-NVX-CoV2373 as a heterologous booster induced non-inferior immune responses as compared to homologous boosters in adults primed with ChAdOx1 nCoV-19 and BBV152. SII-NVX-CoV2373 showed a numerically higher boosting effect than homologous boosters. The vaccine was also safe and well tolerated.
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