Expression of human immunodeficiency virus type 1 vif and vpr mRNAs is Rev-dependent and regulated by splicing.

We have analyzed the structure and expression of the HIV-1 vif and vpr mRNAs. The results revealed that the predominant vif and vpr mRNAs belong to the intermediate size class of HIV-1 mRNAs and that their expression is dependent on the presence of Rev protein. In addition, low levels of a small multiply spliced vpr mRNA were produced by HIV-1. cDNA cloning and expression of vpr cDNAs in eucaryotic cells revealed that high levels of Vpr were produced only from the intermediate-size mRNA in the presence of Rev. Thus, as demonstrated for the viral structural proteins, expression of Vif and Vpr is regulated by Rev. The arrangement of the splice sites and the Rev-RRE interaction are responsible for the regulation of viral expression, and especially for the switching from an early stage, producing only or primarily Tat, Rev, and Nef from multiply spliced mRNAs, to a late stage, leading to the production of Gag, Pol, Env, Vpu, Vif, and Vpr from unspliced and partially spliced mRNAs.     

Production of human immunodeficiency virus type 1 (HIV-1) pseudoviruses using linear HIV-1 envelope expression cassettes

HIV-1 pseudoviruses constitute an important tool in HIV-1 vaccine and entry inhibitor research. Single-cycle pseudoviruses carrying functional envelopes are generated by co-transfecting HEK293T cells with pNL4-3.LucR(-)E(-) and Env expression plasmids. However, cloning of Env genes is time consuming and single Env clones are not representative of the diversity of HIV-1 in a patient's blood sample. A new method to construct Env expression cassettes is proposed which can be used for the rapid generation of heterogeneous HIV-1 pseudoviruses without a cloning step. The linear Env expression cassettes are constructed by ligating PCR amplified Env genes between a 5' CMV promoter and 3' SV40 polyadenylation element. The resulting cassettes generate pseudoviruses carrying heterogeneous Env variants of a primary HIV-1 isolate derived from viral RNA or proviral DNA. The influence of cis-acting sequences upstream of the Env gene on infectivity was compared between pseudoviruses generated from plasmids and linear expression cassettes. The results suggest that the presence of these upstream sequences tends to result in higher infectivity of pseudoviruses when present in heterogeneous Env expression cassettes, but they do not enhance infectivity of pseudoviruses generated with homogeneous Env expression constructs. Using linear expression cassettes allows for the rapid production of heterogeneous patient-derived functional Env genes.     

HIV-1 Cis Enhancing Sequence (CES) enhances CTE-dependent Gag expression

In order to export intron-containing RNA from nucleus, retroviruses use either viral trans-acting factors or constitutive cellular factors interacting with cis-elements in their intron-containing RNA. We have previously identified a Cis Enhancing Sequence (CES) in HIV-1 env region that could co-operate with Rev and RRE to enhance Gag expression by promoting RNA stabilization and exportation. In this study, we found that CES could function in a Rev-independent manner by co-operating with a Constitutive Transport Element (CTE) of Mason-Pfizer monkey viruses (MPMV). RRE and CTE promote intron-containing RNA exportation through different pathways. The fact that CES could function in both pathways of RNA export suggested that CES might function at a common step either up- or downstream to Rev/RRE or CTE functions. Known hnRNP-A1-binding sites as well as other 3 highly conserved sequences in the CES were found to be required for its activity.     

Inhibition of HIV-1 expression by HIV-2

HIV-1 and HIV-2 are co-endemic in certain geographic areas. HIV-2 is more weakly pathogenic than HIV-1, and progression to AIDS occurs less frequently and over a longer period of time. Recent epidemiologic studies suggest that individuals infected with HIV-2 have a lower risk of HIV-1 infection. Both immune mechanisms and various modes of viral interference have been proposed to account for these results. Our findings, described in this paper, suggest that HIV-2 inhibits HIV-1 replication. To study the molecular interactions between HIV-1 and HIV-2, proviral clones were transfected alone or in combination into the human T cell line CEM. LTR-CAT indicator constructs were included for the purpose of monitoring viral promoter activity. Viral replication in transfected cells was monitored by p24 antigen capture assay of cell culture supernatants and Western blot analysis of cell extracts. HIV-2 inhibited HIV-1 replication as determined by intracellular and extracellular p24 antigen levels. Similar results were obtained with simultaneous virus infection using HIV-1 and HIV-2, rather than transfections of proviral DNA. Using cotransfection of HIV-1 and HIV-2 LTR indicator gene constructs, the mechanism of inhibition was found to be suppression of the HIV-1 LTR by HIV-2. The inhibitory effect of HIV-2 is not due to Tat-2, but appears to discriminate between the HIV-1 and HIV-2 LTRs based on differences in the Tat activation response element, TAR. These results suggest both a molecular mechanism for HIV-2 interference with HIV-1 replication and a potential molecular approach to therapy.     

Insulin-like growth factor II mRNA binding protein 1 modulates Rev-dependent human immunodeficiency virus type 1 RNA expression

Human immunodeficiency virus type 1 (HIV-1) needs to overcome cellular counter mechanisms such as to successfully propagate itself. Results of our recent studies show that overexpression of insulin-like growth factor II mRNA binding protein 1 (IMP1) inhibits production of infectious HIV-1 particles through adversely affecting virus maturation. Here, we report that IMP1 interacts with HIV-1 Rev protein and its ectopic expression causes relocation of Rev from the nucleus to the cytoplasm. In accordance with this observation, ectopic expression of IMP1 severely diminishes Rev-dependent expression of CAT enzyme and disturbs HIV-1 RNA expression by causing accumulation of the multiple spliced viral RNA. Results of mutagenesis analysis further reveal that the KH4 domain represents the key element of IMP1 in modulating HIV-1 RNA expression. Taken together, these data suggest, in addition to hampering virus assembly, that IMP1 also has an effect on Rev-dependent viral RNA expression.     

Mu-opioid modulation of HIV-1 coreceptor expression and HIV-1 replication

A substantial proportion of HIV-1-infected individuals are intravenous drug users (i.v.DUs) who abuse opiates. Opioids induce a number of immunomodulatory effects that may directly influence HIV-1 disease progression. In the present report, we have investigated the effect of opioids on the expression of the major HIV-1 coreceptors CXCR4 and CCR5. For these studies we have focused on opiates which are ligands for the mu-opioid receptor. Our results show that DAMGO, a selective mu-opioid agonist, increases CXCR4 and CCR5 expression in both CD3(+) lymphoblasts and CD14(+) monocytes three- to fivefold. Furthermore, DAMGO-induced elevation of HIV-1 coreceptor expression translates into enhanced replication of both X4 and R5 viral strains of HIV-1. We have confirmed the role of the mu-opioid receptor based on the ability of a mu-opioid receptor-selective antagonist to block the effects of DAMGO. We have also found that morphine enhances CXCR4 and CCR5 expression and subsequently increases both X4 and R5 HIV-1 infection. We suggest that the capacity of mu-opioids to increase HIV-1 coreceptor expression and replication may promote viral binding, trafficking of HIV-1-infected cells, and enhanced disease progression.     

HIV-1 p15(Gag)基因的克隆、蛋白表达及抗体制备

目的 为了研究HIV-1 p15(Gag)的生物学活性,制备HIV-1 p15(Gag)蛋白及其特异性抗体.方法 用PCR的方法扩增编码p15(Gag)基因序列,将其克隆到原核表达载体pET28a( )中表达HIV-1 p15蛋白,分别用His抗体和HIV阳性血清做western blot鉴定目的 蛋白.以纯化目的 蛋白为抗原免疫日本大耳白兔,制备多克隆抗体.通过酶联免疫吸附实验(ELISA),免疫细胞化学法检测抗体滴度及其特异性.结果 原核表达载体pET28 a( )-p15(Gag)成功构建,可在大肠杆菌BL21 (DE3)中诱导表达,得到相对分子质量约20000的p15(Gag)蛋白经western blot鉴定正确.纯化蛋白免疫家兔,制备的多克隆抗体具有较强免疫特异性.结论 得到纯化的HIV-1 p15蛋白,制备的多克隆抗体能够检测自然状态下病毒蛋白p15(Gag),为进一步研究HIV-1奠定了实验基础.     

Immunomodulatory effects of intravenous immunoglobulins (IVIGs) in HIV-1 disease: a systematic review

Intravenous immunoglobulins (IVIGs) are generally used as replacement therapy for humoral immunodeficiencies. In consideration of their immune-modulating properties, they are also employed as "immune-modulating/anti-inflammatory" treatment in different clinical conditions. In HIV-1 infection, an increased incidence of autoimmune and auto-inflammatory manifestations has been described, probably as a consequence of the chronic immune activation associated with the disease. The initial use in the treatment of bacterial infections in children with HIV/AIDS has been replaced by the treatment, in combination with antiretroviral therapy, of these autoimmune/inflammatory conditions. We review the results obtained with IVIGs therapy in these HIV-1-associated clinical manifestations.     

Intranasal administration of human immunodeficiency virus type-1 (HIV-1) DNA vaccine with interleukin-2 expression plasmid enhances cell-mediated immunity against HIV-1.

DNA vaccine against human immunodeficiency virus type-1 (HIV-1) can induce substantial levels of HIV-1-specific humoral and cell-mediated immunity. To develop more potent HIV-1 DNA vaccine formulations, we used a murine model to explore the immunomodulatory effects of an interleukin-2 (IL-2) expression plasmid on an HIV-1 DNA vaccine following intranasal administration of the combination. When the vaccine and expression plasmid were incorporated into cationic liposomes and administered to mice, the HIV-1-specific delayed-type hypersensitivity response and cytotoxic T lymphocyte activity were significantly increased. Restimulated immune lymphoid cells showed enhanced production of both IL-2 and interferon-gamma and reduced secretion of IL-4. The level of total antibody to HIV-1 antigen was not greatly changed by coadministration of the DNA vaccine and IL-2 expression plasmid. An analysis of serum HIV-1-specific IgG subclasses showed a significant drop in the IgG1/IgG2a ratio in the group that received the plasmid-vaccine combination. These results demonstrate that the IL-2 expression plasmid strongly enhances the HIV-1-specific immune response via activation of T helper type-1 cells.     

Taxonomic review of Physconelloides (Phthiraptera: Philopteridae) from the Columbiformes (aves), including descriptions of three new species

We provide a comprehensive taxonomic review of Physconelloides, a genus of ischnoceran chewing lice found on pigeons and doves (Columbiformes). Thirteen previously known Physconelloides species are redescribed and 16 new synonymies are designated: P. rubripes Carriker, P. rubripes longulus Tendeiro, P. piotrowskii Tendeiro and P. auritae Tendeiro are synonyms of P. zenaidurae (McGregor); P. recurvatus Eichler, P. chocoensis Carriker and P. montana Carriker are synonyms of P. ceratoceps Ewing; P. silvestris Tendeiro is a synonym of P. perijae Carriker; P. keleri Kaddou and P. branderi Kaddou are synonyms of P. spenceri Emerson and Ward; P. wolfdietrichi Kaddou is a synonym of P. anolaimae Carriker; and Goniocotacanthus mattogrossensis Guimaraes, P. passerinae Emerson, P. eurysema pretiosa Carriker, P. talpacoti Carriker and P. picuii Tendeiro are synonyms of P. eurysema (Carriker). Three new species are also described: P. moyeri (type host Geotrygon linearis), P. johnsoni (type host Columbina passerina bahamensis), and P. robbinsi (type host Metriopelia ceciliae). A key is provided for identification of the 16 recognized species.     

Inhibition of splicing by serine-arginine rich protein 55 (SRp55) causes the appearance of partially spliced HIV-1 mRNAs in the cytoplasm

We have previously shown that SRp55 inhibits splicing from HIV-1 exon 3, thereby generating partially spliced mRNAs encoding HIV-1 vpr. Here we show that SRp55 also inhibits splicing from HIV-1 exon 5 to generate HIV-1 vpu/env mRNA, albeit with lower efficiency. We also show that inhibition of HIV-1 splicing by SRp55 causes the appearance of partially spliced vpu, env and vpr mRNAs in the cytoplasm. SRp55 could also induce production of extracellular p24gag from a rev-defective HIV-1 provirus. These results indicate that SRp55 aids in the generation of partially spliced and unspliced HIV-1 mRNAs.     

Human immunodeficiency virus-type 1 (HIV-1) and the brain

Infection with human immunodeficiency virus Type-1 (HIV-1), the causative agent of AIDS, can be associated with central nervous system as well as immune system disease. Advanced AIDS can be complicated by a dementia. Short of frank dementia, many AIDS patients manifest neuropsychological (NP) impairment including disturbance in speeded information processing, abstraction, learning, and recall. Data conflict on whether medically asymptomatic HIV-1 carriers have subtle NP deficits. Variations in tests chosen, criterion specification, and sample selection may all be contributing to disparate results. Longitudinal research is needed, and this should examine representative samples of HIV-1 seropositive individuals for whom approximate date of seroconversion is known and in whom sources of comorbidity (e.g., drug abuse, concurrent infections, CNS injuries) can be specified.     

Characterization of immunostimulating complexes (ISCOMS) of HIV-1

HIV-1, strain HTLV-III, propagated in H9 cells and purified by sucrose gradient centrifugation, was used as native antigen source for the preparation of immunostimulating complexes, HIV-iscoms. The major antigen detected in the iscom was the cell-derived HLA-DR, which readily could be removed from the virus lysate by immunosorbent. In the iscoms the HIV structural proteins MA p17, p55 and TM gp41 were identified; SU gp120 was present in only minute amounts in the virus lysate. The iscom particles appeared well preserved after freeze drying with a round shape, approximately 35 nm in diameter, comprising morphological subunits, assembled with icosahedral symmetry. Immunization experiments in mice reflected the antigen content of the iscoms. High antibody response was induced to HLA-DR in non-depleted iscoms. Major humoral responses were observed to the viral structural proteins MA p17, CA p24, p55, and also to TM gp41. A low or negligible antibody response to SU gp120 was induced by the HIV-iscoms. The negligible response was, however, overcome by the addition of recombinant gp160 to the virus lysate prior to formation of iscoms, resulting in a preparation evoking a clear serum antibody to gp160.     

Performance of three commercial viral load assays, Versant human immunodeficiency virus type 1 (HIV-1) RNA bDNA v3.0, Cobas AmpliPrep/Cobas TaqMan HIV-1, and NucliSens HIV-1 EasyQ v1.2, testing HIV-1 non-B subtypes and recombinant variants

Monitoring antiretroviral therapy requires that human immunodeficiency virus type 1 (HIV-1) viremia assays are applicable to all distinct variants. This study evaluates the performance of three commercial viral load assays—Versant HIV-1 RNA bDNA v3.0, Cobas AmpliPrep/Cobas TaqMan HIV-1, and NucliSens HIV-1 EasyQ v1.2—in testing 83 plasma specimens from patients carrying HIV-1 non-B subtypes and recombinants previously defined by phylogenetic analysis of the pol gene. All 28 specimens from patients under treatment presented viremia values below the detection limit with the three methods. In the remaining 55 specimens from naive individuals viremia could not be detected in 32.7, 20, and 14.6% using the NucliSens, Versant, or TaqMan tests, respectively, suggesting potential viral load underestimation of some samples by all techniques. Only 32 (58.2%) samples from naive subjects were quantified by the three methods; the NucliSens test provided the highest HIV RNA values (mean, 4.87 log copies/ml), and the Versant test provided the lowest (mean, 4.16 log copies/ml). Viremia differences of greater than 1 log were seen in 8 (14.5%) of 55 specimens, occurring in 10.9, 7.3, and 5.4%, respectively, of the specimens in comparisons of Versant versus NucliSens, Versant versus TaqMan, and TaqMan versus NucliSens. Differences greater than 0.5 log, considered significant for clinicians, occurred in 45.5, 27.3, and 29% when the same assays were compared. Some HIV-1 strains, such as subtype G and CRF02_AG, showed more discrepancies in distinct quantification methods than others. In summary, an adequate design of primers and probes is needed for optimal quantitation of plasma HIV-RNA in non-B subtypes. Our data emphasize the need to use the same method for monitoring patients on therapy and also the convenience of HIV-1 subtyping.     

Translocation t(1;7) revisited. Report of three further cases and review

Three white patients, two with myelofibrosis and one with refractory anemia, presented with a t(1;7). The clinical and cytogenetic findings are discussed in the context of 45 cases already published. Rather than the specific association of t(1;7) with a particular hematologic disorder, a review of the literature strongly suggests correlation with therapeutic or environmental exposure to toxic substances. The proposed mechanisms to explain the origin of t(1;7) are briefly reviewed.     

T-Helper-Cell Proliferative Responses to Whole-Killed Human Immunodeficiency Virus Type 1 (HIV-1) and p24 Antigens of Different Clades in HIV-1-Infected Subjects Vaccinated with HIV-1 Immunogen (Remune)

The discovery of multiple subtypes of human immunodeficiency virus type 1 (HIV-1) worldwide has created new challenges for the development of both therapeutic and preventive AIDS vaccines. We examined T-helper proliferative responses to HIV-1 clade A, B, C, G, and E whole-killed virus and to HIV-1 clade G and B core (p24) antigens in HIV-1-infected subjects taking potent antiviral drugs who received HIV immunogen (Remune) therapeutic vaccination. Subjects who were immunized mounted strong proliferative responses to both whole virus and core antigens of the different clades. These results suggest that a whole-killed immunogen may have broad applications as a therapeutic as well as a preventive vaccine in the current multiclade HIV-1 pandemic.