Prolonged persistence of a novel replication-defective HIV-1 variant in plasma of a patient on suppressive therapy.

BACKGROUND: Cell-free residual HIV-1 virions (RVs) persist in plasma below 20-50 vRNA copies/ml in most patients on suppressive antiretroviral therapy (ART). How RVs are produced in the body during therapy is not fully clear. In this study, we have attempted to characterize these viruses of an ART-treated patient in vitro in order to gain insights into the mechanism of their production in vivo. METHODS: We have reconstructed almost the entire genomes of RVs as DNA forms using the patient's residual plasma vRNA by an overlapping RT-nested PCR method, and then sequence-analyzed the cloned genomes and tested them for their biological activities in vitro. RESULTS: We found that the reconstructed molecular clones of RVs lacked antiretroviral drug-resistant mutations, as well as G-to-A hypermutations. The vDNA clones, when transfected into TZM-bl cells, released HIV-p24 into the culture media at extremely low levels. This low-level virus production was found to be due to the presence of a unique mutation (GU-to-GC) in the conserved 5'-major splice donor (MSD) motif of the corresponding vRNAs. We found that the incorporation of this point mutation by itself could cause defects in the replication of a standard HIV strain (JRCSF) in vitro. However, this novel viral variant was intermittently detected at 5 of 7 time-points in the patient's plasma over a period of 39 months during therapy. CONCLUSIONS: This is the first identification of a natural point mutation (GU-to-GC) in the conserved 5'-MSD motif of HIV genomic RNA. The intermittent but prolonged detection of this replication-defective HIV variant in the patient's plasma among other viral populations strongly suggests that this variant is released from highly stable productively infected cells present in vivo during therapy. The potential implication of this observation is that the elimination of such productively infected cells that contribute to residual viremia during suppressive therapy could be an important first step towards achieving a cure for HIV.

A novel real-time CTL assay to measure designer T-cell function against HIV Env(+) cells.

BACKGROUND: To increase the immunosurveillance in HIV infection, we used retroviral vectors expressing CD4-chimeric antigen receptors (CARs) to genetically modify autologous T cells and redirect CTL toward HIV. The CD4 extracellular domain targets envelope and the intracellular signaling domains activate T cells. The maC46 fusion inhibitor binds HIV and blocks viral replication. METHODS: We stimulated rhesus PBMCs with antibodies to CD3/CD28 and cotransduced T cells with CD4-CAR and maC46 vectors. CD4-CAR-transduced T cells were added to Env(+) 293T cells at E:T of 1:1. Killing of target cells was measured as reduced impedance. RESULTS: We observed gene expression in 60-70% of rhesus CD3(+) CD8(+) T cells with the individual vectors and in 35% of the cells with both vectors. CD4-CAR-transduced populations specifically killed Env(+) cells. CONCLUSIONS: In these studies, we showed that designer T cells were redirected to kill Env(+) cells. Control of viremia without HAART would revolutionize treatment for HIV patients.

Malnutrition as a potential predictor of mortality in chronic kidney disease patients on dialysis: A systematic review and meta-analysis.

BACKGROUND & AIMS: Malnutrition, a significant problem in patients with chronic kidney disease (CKD), is linked to lower health-related quality of life, longer and more frequent hospital admissions, worse functional capacity, and higher levels of morbidity. However, the extent of its impact on mortality is poorly elucidated. This systematic review and meta-analysis aimed to investigate the impact of malnutrition on mortality among CKD patients on dialysis. METHODS: This meta-analysis was designed and performed in accordance with the PRISMA guidelines (CRD42023394584). A systematic electronic literature search was conducted in PubMed, ScienceDirect, and Embase to identify relevant cohort studies. The studies that reported nutritional status and its impact on mortality in patients were considered for analysis. The generic inverse variance method was used to pool the hazard ratio effect estimates by employing a random effects model. The Newcastle-Ottawa scale was used for the quality assessment. The statistical analysis was performed by utilizing RevMan and CMA 2.0. RESULTS: A total of 29 studies that comprised 11,063 patients on dialysis whose nutritional status was evaluated were eligible for quantitative analysis. Based on a comparison between the "malnutrition" category and the reference "normal nutrition status" category, the results showed that the overall pooled hazard risk (HR) for mortality was (HR 1.49, 95% CI: 1.36-1.64, p < 0.0001). According to the subgroup analysis, the hemodialysis subgroup had greater mortality hazards (HR 1.53; 95% CI 1.38-1.70, p < 0.0001), compared to the peritoneal dialysis subgroup (HR 1.26; 95% CI 1.15-1.37, p < 0.00001). Additionally, the overall incidence of mortality was explored but the authors were unable to combine the results due to limitations with the data. CONCLUSION: The findings conclude that malnutrition is a strong predictor of mortality among patients on dialysis, with the hemodialysis subgroup having a higher mortality hazard compared to the peritoneal dialysis subgroup. The results of this study will advocate for early nutritional evaluation and timely dietary interventions to halt the progression of CKD and death.

Recovery of replication-competent residual HIV-1 from plasma of a patient receiving prolonged, suppressive highly active antiretroviral therapy.

The clinical significance of persistent residual viremia in patients on prolonged highly active antiretroviral therapy (HAART) is not clear. Moreover, it remains to be demonstrated whether residual viremia consists of viruses capable of spreading infection in vivo upon termination of therapy. Using residual viral RNAs (vRNAs) isolated from a HAART-treated patient's plasma, we cloned full-length viral genomes and found that most of them could produce infectious, replication-competent HIVs when transfected into TZM-bl cells, suggesting that residual viruses produced in the absence of therapy can initiate fresh cycles of infection and spread in host cells. The data further indicate that residual viremia may pose a major concern with regard to the emergence of drug-resistant HIVs during periods of low adherence to therapy.

Latent HIV in primary T lymphocytes is unresponsive to histone deacetylase inhibitors.

Recently, there is considerable interest in the field of anti-HIV therapy to identify and develop chromatin-modifying histone deacetylase (HDAC) inhibitors that can effectively reactivate latent HIV in patients. The hope is that this would help eliminate cells harboring latent HIV and achieve an eventual cure of the virus. However, how effectively these drugs can stimulate latent HIVs in quiescent primary CD4 T cells, despite their relevant potencies demonstrated in cell line models of HIV latency, is not clear. Here, we show that the HDAC inhibitors valproic acid (VPA) and trichostatin A (TSA) are unable to reactivate HIV in latently infected primary CD4 T cells generated in the H80 co-culture system. This raises a concern that the drugs inhibiting HDAC function alone might not be sufficient for stimulating latent HIV in resting CD4 T cells in patients and not achieve any anticipated reduction in the pool of latent reservoirs.

Low-level plasma HIVs in patients on prolonged suppressive highly active antiretroviral therapy are produced mostly by cells other than CD4 T-cells.

The cellular source(s) and the clinical significance of persistent low-level viremia, below 50 HIV RNA copies per ml of plasma, achieved in many patients with high adherence to highly active antiretroviral therapy (HAART) remain unclear. Also, it is not clear if residual plasma HIVs during HAART can become predominant populations in the rebounding plasma viral loads after therapy interruption. Since, different HIV quasispecies tend to compartmentalize in various cell types and tissue locations in patients during chronic infection, the phylogenetic relationships between HIV sequences amplified from residual plasma viruses and CD4 T cells of five patients on long-term suppressive therapy were examined. Three of these patients stopped therapy voluntarily for 3 weeks, but only one of them demonstrated viral load rebound in plasma. In phylogenetic analyses, the residual plasma viruses were found to be distinct genetically from the majority of CD4 T cell-associated virus populations in four of five patients. The compartmental analyses revealed that in all patients, plasma- and CD4 T cell-derived viral sequences were compartmentalized separately. Interestingly, the plasma sequences obtained before and after HAART-off in two patients were produced apparently from the same compartment, which was different from the circulating CD4 T cell-compartment. These results suggest the possibility that residual plasma viruses in patients on long-term suppressive HAART may be produced persistently from a cellular source yet to be identified, and are capable of spreading quickly in vivo, accounting for the rapid rebound of viral loads in plasma after therapy interruption.

Detection of very early antibody to native HIV antigens by HIV neutralization and live-cell immunofluorescence assays.

Very early detection of HIV infection could help decrease the spread of HIV, improve safety of the blood supply, and permit earlier treatment. Early detection was reported when native gp41 antigen was used to detect antibodies that occurred 2-6 weeks earlier than detection of antibodies to denatured antigens by the current EIA or WB tests or detection by the HIV RNA test. We hypothesized that early antibodies to native gp41/160 could be detected, not only by the reported live-cell immunofluorescence (IFA) but also by a neutralization test, since virions as well as HIV-infected cells contain native gp41/160. To test this hypothesis, we did an initial test of concept study to compare the neutralization test with other tests, using sera from 12 high-risk patients. The neutralization test reproducibly detected early antibodies (characterized) in the sera of 10 of 12 (83%) high-risk subjects. Importantly, the EIA and WB tests that use denatured antigens missed the early diagnosis in 12 of the 13 subjects (92%). The findings support the concept that native HIV antigens can detect polyclonal HIV neutralizing antibodies and live-cell IFA antibodies earlier than currently available tests that use denatured antigens.

Potential implication of residual viremia in patients on effective antiretroviral therapy.

The current antiretroviral therapy (ART) has suppressed viremia to below the limit of detection of clinical viral load assays; however, it cannot eliminate viremia completely in the body even after prolonged treatment. Plasma HIV-1 loads persist at extremely low levels below the clinical detection limit. This low-level viremia (termed "residual viremia") cannot be abolished in most patients, even after the addition of a new class of drug, i.e., viral integrase inhibitor, to the combined antiretroviral regimens. Neither the cellular source nor the clinical significance of this residual viremia in patients on ART remains fully clear at present. Since residual plasma viruses generally do not evolve with time in the presence of effective ART, one prediction is that these viruses are persistently released at low levels from one or more stable but yet unknown HIV-1 reservoirs in the body during therapy. This review attempts to emphasize the source of residual viremia as another important reservoir (namely, "active reservoir") distinct from the well-known latent HIV-1 reservoir in the body, and why its elimination should be a priority in the effort for HIV-1 eradication.

Anti-HIV designer T cells progressively eradicate a latently infected cell line by sequentially inducing HIV reactivation then killing the newly gp120-positive cells.

The current antiretroviral therapy (ART) can effectively reduce plasma HIV loads to undetectable levels, but cannot eliminate latently infected resting memory CD4 T cells that persist for the lifetime of infected patients. Therefore, designing new therapeutic approaches to eliminate these latently infected cells or the cells that produce HIV upon reactivation from latency is a priority in the ART era in order to progress to a cure of HIV. Here, we show that "designer" T cells expressing chimeric antigen receptor (CAR), CD4-CD28-CD3ζ, can target and kill HIV Env-expressing cells. Further, they secrete effector cytokines upon contact with HIV Env+ target cells that can reactivate latent HIV in a cell line model, thereby exposing those cells to recognition and killing by anti-HIV CAR+ T cells. Taken to the limit, this process could form the basis for an eventual functional or sterilizing cure for HIV in patients.

A novel in vitro system to generate and study latently HIV-infected long-lived normal CD4+ T-lymphocytes.

Studies of mechanisms of HIV-latency and its reactivation in long-lived resting CD4+ T-lymphocytes in patients have been limited due to the very low frequency of these cells ( approximately 1-10 cells per 10(6) CD4+ T-cells). To circumvent this obstacle, an in vitro culture system for post-activation long-term survival of normal CD4+ T-cells in a quiescent (non-cycling) state was developed and used to generate latently infected, long-lived quiescent CD4+ T-cells from HIV-infected, activated normal CD4+ T-lymphocytes. This yielded a frequency of approximately 5x10(4) latently infected cells per 10(6) cells in culture, which is approximately 10(3)- to 10(4)-fold higher than that available from patients. Moreover, 5-10% of long-term surviving non-cycling T-cells were found to make infectious HIV continuously at low levels, showing that HIV production from infected T-cells does not require full cellular activation. This model system should facilitate studies of long-lived, latently infected and persistently HIV-producing quiescent normal CD4+ T-lymphocytes.

HIV-1 induces IL-10 production in human monocytes via a CD4-independent pathway.

In HIV-infected patients, increased levels of IL-10, mainly produced by virally infected monocytes, were reported to be associated with impaired cell-mediated immune responses. In this study, we investigated how HIV-1 induces IL-10 production in human monocytes. We found that CD14(+) monocytes infected by either HIV-1(213) (X4) or HIV-1(BaL) (R5) produced IL-10, IL-6, tumor necrosis factor-alpha (TNF-alpha), and to a lesser extent, IFN-gamma. However, the capacity of HIV-1 to induce these cytokines was not dependent on virus replication since UV-inactivated HIV-1 induced similar levels of these cytokines. In addition, soluble HIV-1 gp160 could induce CD14(+) monocytes to produce IL-10 but at lower levels. Cross-linking CD4 molecules (XLCD4) with anti-CD4 mAbs and goat anti-mouse IgG (GAM) resulted in high levels of IL-6, TNF-alpha and IFN-gamma but no IL-10 production by CD14(+) monocytes. Interestingly, neither anti-CD4 mAbs nor recombinant soluble CD4 (sCD4) receptor could block IL-10 secretion induced by HIV-1(213), HIV-1(BaL) or HIV-1 gp160 in CD14(+) monocytes, whereas anti-CD4 mAb or sCD4 almost completely blocked the secretion of the other cytokines. Furthermore, HIV-1(213) could induce IL-10 mRNA expression in CD14(+) monocytes while XLCD4 by anti-CD4 mAb and GAM failed to do so. As with IL-10 protein levels, HIV-1(213)-induced IL-10 mRNA expression in CD14(+) monocytes could not be inhibited by anti-CD4 mAb or sCD4. Taken together, HIV-1 binding to CD14(+) monocytes can induce CD4-independent IL-10 production at both mRNA and protein levels. This finding suggests that HIV induces the immunosuppressive IL-10 production in monocytes and is not dependent on CD4 molecules and that interference with HIV entry through CD4 molecules may have no impact on counteracting the effects of IL-10 during HIV infection.

Out-of-frame versus in-frame core internal deletion variants of human and woodchuck hepatitis B viruses.

Human hepatitis B virus (HBV) variants containing in-frame core internal deletion (CID) have been demonstrated to contain all the functional features of defective interfering (DI) particles (Yuan, T. T.-T., M.-H. Lin, D. S. Chen, and C. Shih, 1998, J. Virol. 72, 578-584). Here, we report that out-of-frame HBV CID variants exhibit defective interfering property similar to in-frame CID variants characterized previously. This result raises the possibility that it may be the deleted pregenomic RNA product, rather than the deleted core protein product, that is responsible for interference. Furthermore, a genomic deletion elsewhere does not cause interference since preS2 deletion variants exhibit no influence on wild-type HBV replication. Consistent with the natural occurrence of HBV CID variants, we recently identified CID variants of woodchuck hepatitis virus (WHV) in natural infection. However, unlike HBV CID variants, functional characterization of WHV CID variants using a human hepatoma cell line has not revealed any interference in tissue culture. In summary, defective interference is a general phenomenon for both in-frame and out-of-frame HBV CID variants.

Detection of antibodies to human immunodeficiency virus (HIV) that recognize conformational epitopes of glycoproteins 160 and 41 often allows for early diagnosis of HIV infection.

On the basis of human immunodeficiency virus (HIV) needlestick studies, the time to seroconversion for anti-HIV antibodies is 1-9 months (mean, approximately 2-3 months). However, an earlier marker of an immune response to HIV often occurs-serum anti-HIV antibodies reactive with live HIV-infected cells, termed "early HIV antibodies." The specificities of these antibodies are characterized by the recognition of type-specific conformational epitopes of the HIV envelope glycoprotein (gp) 160 and gp41. By use of a third-generation native HIV(IIIB) gp160 enzyme immunoassay (EIA), detection of HIV antibodies occurred, on average, 33 days earlier than did detection by commercial EIA and 25 days earlier than did detection by the reference antigen and reverse-transcription polymerase chain reaction (RT-PCR) assays in 3 of 5 HIV seroconversion panels. A fourth panel possessed early HIV antibodies that reacted with HIV(213) but not with HIV(IIIB), allowing for detection of HIV antibodies approximately 3 weeks earlier than by RT-PCR or other current tests.