Adjunctive passive immunotherapy in human immunodeficiency virus type 1-infected individuals treated with antiviral therapy during acute and early infection

Three neutralizing monoclonal antibodies (MAbs), 2G12, 2F5, and 4E10, with activity in vitro and in vivo were administered in an open-label, nonrandomized, proof-of-concept study to attempt to prevent viral rebound after interruption of antiretroviral therapy (ART). Ten human immunodeficiency virus type 1-infected individuals identified and treated with ART during acute and early infection were enrolled. The first six patients were administered 1.0 g of each of the three MAbs per infusion. The remaining four patients received 2G12 at 1.0 g/infusion and 2.0 g/infusion of 2F5 and 4E10. The MAbs were well tolerated. Grade I post-partial thromboplastin time prolongations were noted. Viral rebound was observed in 8/10 subjects (28 to 73 days post-ART interruption), and 2/10 subjects remained aviremic over the course of the study. In seven of eight subjects with viral rebound, clear resistance to 2G12 emerged, whereas reductions in the susceptibilities of plasma-derived recombinant viruses to 2F5 and 4E10 were neither sustained nor consistently measured. Viral rebound was associated with a preferential depletion of CD4(+) T cells within the gastrointestinal tract. Though safe, the use of MAbs generally delayed, but did not prevent, virologic rebound. Consideration should be given to further pilot studies with alternative combinations of MAbs and perhaps additional novel treatment modalities.     

1例耐多药复杂重组人类免疫缺陷病毒1型亚型感染病例的抗病毒治疗

随着抗病毒治疗时间的延长,如何处理人类免疫缺陷病毒（HIV）耐药患者是临床医师面对的一个挑战。本文报道对1例耐多药复杂重组HIV-1亚型感染病例成功进行抗病毒治疗的过程,总结了抗病毒依从性的重要性,即只有规律服药才能达到好的治疗效果。临床上可应用病毒基因耐药检测来指导抗病毒药物的选择,但应注意体外实验与体内实际情况可能存在的差异。此外,需进一步研究一些少见亚型毒株对药物的反应及对药物压力的逃避机制。     

Viral dynamics of primary viremia and antiretroviral therapy in simian immunodeficiency virus infection.

Mathematical modeling of viral replication dynamics, based on sequential measurements of levels of virion-associated RNA in plasma during antiretroviral treatment, has led to fundamental new insights into human immunodeficiency virus type 1 pathogenesis. We took advantage of the simian immunodeficiency virus (SIV)-infected macaque model to perform detailed measurements and mathematical modeling during primary infection and during treatment of established infection with the antiretroviral drug (R)-9-(2-phosphonylmethoxypropyl)adenine (PMPA). The calculated clearance half-life for productively infected cells during resolution of the peak viremia of primary infection was on the order of 1 day, with slightly shorter clearance half-lives calculated during PMPA treatment. Viral reproduction rates upon discontinuation of PMPA treatment after 2 weeks were approximately twofold greater than those obtained just prior to initiation of treatment in the same animals, likely reflecting accumulation of susceptible target cells during treatment. The basic reproductive ratio (R0) for the spread of SIV infection in vivo, which represents the number of productively infected cells derived from each productively infected cell at the beginning of infection, was also estimated. This parameter quantifies the extent to which antiviral therapy or vaccination must limit the initial spread of virus to prevent establishment of chronic disseminated infection. The results thus provide an important guide for efforts to develop vaccines against SIV and, by extension, human immunodeficiency virus.     

Dynamics of intermittent viremia during highly active antiretroviral therapy in patients who initiate therapy during chronic versus acute and early human immunodeficiency virus type 1 infection

The meaning of viral blips in human immunodeficiency virus type 1 (HIV-1)-infected patients treated with seemingly effective highly active antiretroviral therapy (HAART) is still controversial and under investigation. Blips might represent low-level ongoing viral replication in the presence of drug or simply release of virions from the latent reservoir. Patients treated early during HIV-1 infection are more likely to have a lower total body viral burden, a homogenous viral population, and preserved HIV-1-specific immune responses. Consequently, viral blips may be less frequent in them than in patients treated during chronic infection. To test this hypothesis, we compared the occurrence of viral blips in 76 acutely infected patients (primary HIV infection [PHI] group) who started therapy within 6 months of the onset of symptoms with that in 47 patients who started HAART therapy during chronic infection (chronic HIV infection [CHI] group). Viral blip frequency was approximately twofold higher in CHI patients (0.122 +/- 0.12/viral load [VL] sample, mean +/- standard deviation) than in PHI patients (0.066 +/- 0.09/VL sample). However, in both groups, viral blip frequency did not increase with longer periods of observation. Also, no difference in viral blip frequency was observed between treatment subgroups, and the occurrence of a blip was not associated with a recent change in CD4(+) T-cell count. Finally, in PHI patients the VL set point was a significant predictor of blip frequency during treatment.     

Safety and immunogenicity of ALVAC vCP1452 and recombinant gp160 in newly human immunodeficiency virus type 1-infected patients treated with prolonged highly active antiretroviral therapy

In order to boost immune responses in persons in whom highly active antiretroviral therapy (HAART) was initiated within 120 days of the onset of symptoms of newly acquired human immunodeficiency virus type 1 (HIV-1) infection, we administered vaccines containing a canarypox virus vector, vCP1452, with HIV-1 genes encoding multiple HIV-1 proteins, and recombinant gp160. Fifteen HIV-1-infected subjects who achieved sustained suppression of plasma viremia for at least 2 years were enrolled. While continuing antiretroviral therapy, each subject received at least four intramuscular injections of the vaccines on days 0, 30, 90, and 180. Adverse events were mild, with the most common being transient tenderness at the vCP1452 injection site. Of the 14 patients who completed vaccination, 13 had significant increases in anti-gp120 or anti-p24 antibody titers, and 9 had transient augmentation of their T-cell proliferation responses to gp160 and/or p24. HIV-1-specific CD8(+) T cells were quantified using an intracellular gamma interferon staining assay. Among 11 patients who had increased CD8(+) T-cell responses, seven had responses to more than one HIV-1 antigen. In summary, vaccination with vCP1452 and recombinant gp160 appears safe and immunogenic in newly HIV-1-infected patients on HAART.     

Both R5 and X4 human immunodeficiency virus type 1 variants persist during prolonged therapy with five antiretroviral drugs

A viral reservoir of human immunodeficiency virus type 1 (HIV-1)-infected, resting CD4(+) T cells persists despite suppression of plasma viremia by combination antiretroviral therapy. In a longitudinal analysis of three patients treated with a five-drug regimen, both R5 and X4 HIV-1 variants persisted in the cellular reservoir for up to 3 years.     

人类免疫缺陷病毒1型慢性感染者B细胞表型分析及抗反转录病毒治疗的修复作用

人类免疫缺陷病毒1型（HIV-1）感染会造成严重的免疫功能损伤,除引起CD4＋ T细胞不断耗损和功能损伤外,体液免疫应答也受到损伤。本研究通过检测HIV-1慢性感染者和慢性感染治疗者外周血B细胞数目和亚群比例,以及活化、凋亡和共刺激分子的表达,探讨 HIV-1感染者中B细胞损伤及抗反转录病毒治疗（ART）对B细胞损伤的修复作用。结果显示,HIV-1慢性感染者外周血B细胞数目显著低于健康对照组,其中未成熟B细胞、初始B细胞、静息记忆B细胞和浆母细胞显著降低,而组织样记忆B细胞显著增加, ART可恢复初始B细胞和组织样记忆B细胞比例,但不能恢复静息记忆B细胞比例。与健康对照组相比, HIV-1感染者未成熟B细胞、初始B细胞、静息记忆B细胞和组织样记忆B细胞中CD38的表达上调;CD95的表达在所有B细胞亚群中均上调;而Bcl-2在初始B细胞、组织样记忆B细胞和浆母细胞中的表达显著降低;静息记忆B细胞和浆母细胞中PD-1的表达上调;共刺激分子CD40在所有B细胞亚群中的表达降低,而CD70的表达在未成熟B细胞以外的亚群中均显著下调。ART仅能部分修复以上分子的表达。结果表明, HIV-1感染引起B细胞及其亚群比例异常,B细胞表现为过度活化、易凋亡及与T细胞作用受损,ART不能完全修复B细胞损伤,有效的免疫干预策略亟待开发。     

Use of real-time PCR and molecular beacons to detect virus replication in human immunodeficiency virus type 1-infected individuals on prolonged effective antiretroviral therapy.

We have designed a novel, precise, and sensitive assay to measure unspliced (US) human immunodeficiency virus type 1 (HIV-1) mRNA in peripheral blood mononuclear cells of HIV-1-infected individuals by using real-time PCR and molecular beacons. Individuals were classified as either well suppressed (WS) or partially suppressed, based on longitudinal measurements of plasma HIV-1 RNA. The proportion of individuals with US mRNA undetectable over time was significantly higher among WS individuals; however, 30% of WS subjects still had detectable US mRNA after 24 months of effective antiviral therapy.     

Relative dominance of epitope-specific cytotoxic T-lymphocyte responses in human immunodeficiency virus type 1-infected persons with shared HLA alleles.

Cytotoxic T lymphocytes (CTL) target multiple epitopes in human immunodeficiency virus (HIV)-infected persons, and are thought to influence the viral set point. The extent to which HLA class I allele expression predicts the epitopes targeted has not been determined, nor have the relative contributions of responses restricted by different class I alleles within a given individual. In this study, we performed a detailed analysis of the CTL response to optimally defined CTL epitopes restricted by HLA class I A and B alleles in individuals who coexpressed HLA A2, A3, and B7. The eight HIV-1-infected subjects studied included two subjects with acute HIV infection, five subjects with chronic HIV infection, and one long-term nonprogressor. Responses were heterogeneous with respect to breadth and magnitude of CTL responses in individuals of the same HLA type. Of the 27 tested epitopes that are presented by A2, A3, and B7, 25 were targeted by at least one person. However, there was wide variation in the number of epitopes targeted, ranging from 2 to 17. The A2-restricted CTL response, which has been most extensively studied in infected persons, was found to be narrowly directed in most individuals, and in no cases was it the dominant contributor to the total HIV-1-specific CTL response. These results indicate that HLA type alone does not predict CTL responses and that numerous potential epitopes may not be targeted by CTL in a given individual. These data also provide a rationale for boosting both the breadth and the magnitude of HIV-1-specific CTL responses by immunotherapy in persons with chronic HIV-1 infection.     

Neutralizing antibodies associated with viremia control in a subset of individuals after treatment of acute human immunodeficiency virus type 1 infection

Immediate treatment of acute human immunodeficiency virus type 1 (HIV-1) infection has been associated with subsequent control of viremia in a subset of patients after therapy cessation, but the immune responses contributing to control have not been fully defined. Here we examined neutralizing antibodies as a correlate of viremia control following treatment interruption in HIV-1-infected individuals in whom highly active antiretriviral therapy (HAART) was initiated during early seroconversion and who remained on therapy for 1 to 3 years. Immediately following treatment interruption, neutralizing antibodies were undetectable with T-cell-line adapted strains and the autologous primary HIV-1 isolate in seven of nine subjects. Env- and Gag-specific antibodies as measured by enzyme-linked immunosorbent assay were also low or undetectable at this time. Despite this apparent poor maturation of the virus-specific B-cell response during HAART, autologous neutralizing antibodies emerged rapidly and correlated with a spontaneous downregulation in rebound viremia following treatment interruption in three subjects. Control of rebound viremia was seen in other subjects in the absence of detectable neutralizing antibodies. The results indicate that virus-specific B-cell priming occurs despite the early institution of HAART, allowing rapid secondary neutralizing-antibody production following treatment interruption in a subset of individuals. Since early HAART limits viral diversification, we hypothesize that potent neutralizing-antibody responses to autologous virus are able to mature and that in some persons these responses contribute to the control of plasma viremia after treatment cessation.     

Productive and lytic infection of human CD4+ type 1 helper T cells with macrophage-tropic human immunodeficiency virus type 1.

It is generally recognized that macrophage-tropic human immunodeficiency virus type 1 (HIV-1) is the predominant population during the acute and asymptomatic phases of HIV-1 infection. Here, we compared the proliferation and syncytium-inducing activities of different HIV-1 strains in primary CD4+ T cells expressing various helper T (Th)-type cytokine profiles. The macrophage-tropic HIV-1 strains HIV-1JR-CSF, HIV-1NFN-SX, and HIV-1SF162 could proliferate vigorously and generate syncytia in primary CD4+ T cells irrespective of their Th subtype, in contrast to the T-cell-line-tropic HIV-1 strains HIV-1NL4-3 and HIV-1IIIB, which favored non-type 1 Th conditions. These results indicate that macrophage-tropic HIV-1 may be more invasive and virulent, since it kills more CD4+ Th1 cells than T-cell-line-tropic HIV-1 during the early stages of HIV-1 infection, when the Th1 immune response is dominant.     

Interleukin-8 stimulates human immunodeficiency virus type 1 replication and is a potential new target for antiretroviral therapy

Production of the C-X-C chemokines interleukin-8 (IL-8) and growth-regulated oncogene alpha (GRO-alpha) in macrophages is stimulated by exposure to human immunodeficiency virus type 1 (HIV-1). We have demonstrated previously that GRO-alpha then stimulates HIV-1 replication in both T lymphocytes and macrophages. Here we demonstrate that IL-8 also stimulates HIV-1 replication in macrophages and T lymphocytes. We further show that increased levels of IL-8 are present in the lymphoid tissue of patients with AIDS. In addition, we demonstrate that compounds which inhibit the actions of IL-8 and GRO-alpha via their receptors, CXCR1 and CXCR2, also inhibit HIV-1 replication in both T lymphocytes and macrophages, indicating potential therapeutic uses for these compounds in HIV-1 infection and AIDS.     

Stability in controlling viral replication identifies long-term nonprogressors as a distinct subgroup among human immunodeficiency virus type 1-infected persons.

Long-term nonprogressors (LTNPs) of human immunodeficiency virus type 1 (HIV-1) infection are characterized by low levels of HIV-1 replication and viral load. However, it has not been established whether they differ in this regard from progressors from the very early stage of infection. By studying peripheral blood mononuclear cell (PBMC) specimens from a longitudinally monitored cohort of HIV-1-infected men, we found that HIV-1 proviral copy numbers and HIV-1 mRNA expression levels as low or lower than those seen in seven carefully selected LTNPs were commonly observed in specimens collected soon after seroconversion from 28 subjects who became infected while under observation. However, only the LTNPs were able to stably maintain such an efficient viral control over time. Because of the instability of the early control of HIV-1 replication, the predictive value of HIV-1 mRNA expression in PBMCs at postseroconversion was found to be limited but significantly increased during the first year of infection. Besides their diagnostic implications, these data support the idea that LTNPs may be a pathophysiologically distinct subgroup among persons infected with HIV-1.     

Defective accessory genes in a human immunodeficiency virus type 1-infected long-term survivor lacking recoverable virus.

We have been studying a patient who acquired human immunodeficiency virus (HIV) infection via a blood transfusion 13 years ago. She has remained asymptomatic since that time. The blood donor and two other recipients have all died of AIDS. Although this patient has shown persistently strong seroreactivity to HIV type 1 (HIV-1) antigens by Western blot (immunoblot), she has been continually HIV culture negative in results from multiple laboratories over the last 6 years and has a very low viral burden. Her CD4+ T-cell count has fluctuated around a mean of 399 cells per microliters, with little change in lymphocyte subset percentages. Strong cellular immune responses to HIV-1 epitopes by this patient have been demonstrated. We now report the results of an intensive molecular genetic analysis of the HIV-1 proviral quasispecies from this patient sampled over 5 years. Long terminal repeat region sequences supported the argument for normal basal and Tat-mediated promoter activities. Sequential sequencing of the nef gene revealed a low frequency (8.3%) of defective genes and a striking lack of sequence evolution. Functional analysis of predominant nef genes by both a cell surface CD4 downregulation and a viral infectivity complementation assay showed wild-type function. In contrast, sequential analysis of an amplicon containing the vif, vpr, vpu, tat1, and rev1 genes revealed the presence of inactivating mutations in 64% of the clones. These data suggest that this patient, initially infected with a virulent swarm of HIV-1, is presently infected with a more-attenuated viral quasispecies as a result of effective host immunity.     

Productive infection of plasmacytoid dendritic cells with human immunodeficiency virus type 1 is triggered by CD40 ligation

Immature plasmacytoid dendritic cells are the principal alpha interferon-producing cells (IPC), responsible for primary antiviral immunity. IPC express surface molecules CD4, CCR5, and CXCR4, which are known coreceptors required for human immunodeficiency virus (HIV) infection. Here we show that IPC are susceptible to and replicate HIV type 1 (HIV-1). Importantly, viral replication is triggered upon activation of IPC with CD40 ligand, a signal physiologically delivered by CD4 T cells. Immunohistochemical staining of tonsil from HIV-infected individuals reveals HIV p24(+) IPC, consistent with in vivo infection of these cells. IPC exposed in vitro to HIV produce alpha interferon, which partially inhibits viral replication. Nevertheless, IPC efficiently transmit HIV-1 to CD4 T-cells, and such transmission is also augmented by CD40 ligand activation. IPC produce RANTES/CCL5 and MIP-1alpha/CCL3 when exposed to HIV in vitro. IPC also induce na?ve CD4 T cells to proliferate and would therefore preferentially infect these cells. These results indicate that IPC may play an important role in the dissemination of HIV.     

Virus-specific cytotoxic T lymphocytes in human immunodeficiency virus type 1-infected chimpanzees.

Chimpanzees have been important in studies of human immunodeficiency virus type 1 (HIV-1) pathogenesis and in evaluation of HIV-1 candidate vaccines. However, little information is available about HIV-1-specific cytotoxic T lymphocytes (CTL) in these animals. In the present study, in vitro stimulation of peripheral blood mononuclear cells (PBMC) from infected chimpanzees with HIV-1 Gag peptides was shown to be a sensitive, reproducible method of expanding HIV-1-specific CD8(+) effector CTL. Of interest, PBMC from two chimpanzees had CTL activity against Gag epitopes also recognized by major histocompatibility complex class I-restricted CTL from HIV-1-infected humans. The use of peptide stimulation will help to clarify the role of CTL in vaccine-mediated protection and HIV-1 disease progression in this important animal model.