Targeting anxiety to improve quality of life in patients with schizophrenia.

BACKGROUND: Several studies suggested that anxiety can significantly affect the outcome of schizophrenia. Despite this evidence, non-pharmacological interventions targeting anxiety are still heterogenous. This study aims to test the efficacy of a novel training specifically designed to target anxiety in patients with schizophrenia. Innovatively, this training, beyond psychoeducation and problem solving, also targets Theory of Mind, as it provides coping strategies. METHOD: Twenty-seven outpatients with schizophrenia received a novel rehabilitative training targeting anxiety (Anxiety Management Group [AMG]) combined with a Computer-Assisted Cognitive Remediation (CACR), and twenty received CACR plus a control intervention (Control Newspaper discussion Group [CNG]). All patients were assessed at baseline and after treatment for quality of life, neurocognition and anxiety. RESULTS: After training, patients treated with AMG+CACR showed significantly greater improvements on anxiety. A significant increase in quality of life was observed only for AMG+CACR group. Moreover, the participants' appraisal showed a significant difference between treatment groups with higher ratings among patients who received the AMG+CACR. CONCLUSIONS: This study thus suggests feasibility and efficacy of the proposed intervention, that could be implemented in rehabilitative programs for patients with schizophrenia with potential benefits also on disease course and outcome.

Cognitive remediation and functional improvement in schizophrenia: Is it a matter of size?

BACKGROUND: Cognitive Remediation represents the best available tool to treat cognitive deficits in schizophrenia and evidence suggests an effect also on global functioning. However, the relationship between cognitive and functional improvement is not yet fully elucidated: do cognitive changes need to be of a definite size and/or encompass a certain number of domains in order to impact on daily functioning? This study aims to explore the role of cognitive improvement, evaluated both quantitatively and qualitatively through the use of Italian equivalent scores, on the daily functioning of patients. As secondary goal, the influence of demographic, clinical and neuropsychological variables on functional outcome was also systematically investigated. METHODS: One hundred subjects with a diagnosis of schizophrenia underwent 36 sessions of Cognitive Remediation and were evaluated at baseline and after the training with the Brief Assessment of Cognition in Schizophrenia and the Quality of Life Scale. RESULTS: A total of 70% of patients improved in at least one cognitive domain and over 50% obtained a normalized score. Among the clinical and neurocognitive factors examined, the only significant predictor of quality of life's improvement was the proportion of cognitive functions that reached an equivalent score of "normal". CONCLUSIONS: This study suggests that improvements in daily functioning depend on the achievement of a cognitive profile as much as possible "normal", harmonious and balanced, supporting the idea that a qualitative leap in cognition is needed in order to gain an advantage in real life activities.

Combined social cognitive and neurocognitive rehabilitation strategies in schizophrenia: neuropsychological and psychopathological influences on Theory of Mind improvement.

BACKGROUND: Neurocognitive and social cognitive impairments represent important treatment targets in schizophrenia, as they are significant predictors of functional outcome. Different rehabilitative interventions have recently been developed, addressing both cognitive and psychosocial domains. Although promising, results are still heterogeneous and predictors of treatment outcome are not yet identified. In this study we evaluated the efficacy of two newly developed social cognitive interventions, respectively based on the use of videotaped material and comic strips, combined with domain-specific Cognitive Remediation Therapy (CRT). We also analysed possible predictors of training outcome, including basal neurocognitive performance, the degree of cognitive improvement after CRT and psychopathological variables. METHOD: Seventy-five patients with schizophrenia treated with CRT, were randomly assigned to: social cognitive training (SCT) group, Theory of Mind Intervention (ToMI) group, and active control group (ACG). RESULTS: ANOVAs showed that SCT and ToMI groups improved significantly in ToM measures, whereas the ACG did not. We reported no influences of neuropsychological measures and improvement after CRT on changes in ToM. Both paranoid and non-paranoid subjects improved significantly after ToMI and SCT, without differences between groups, despite the better performance in basal ToM found among paranoid patients. In the ACG only non-paranoid patients showed an improvement in non-verbal ToM. CONCLUSION: Results showed that both ToMI and SCT are effective in improving ToM in schizophrenia with no influence of neuropsychological domains. Our data also suggest that paranoid symptoms may discriminate between different types of ToM difficulties in schizophrenia.

Combined neurocognitive and metacognitive rehabilitation in schizophrenia: Effects on bias against disconfirmatory evidence.

BACKGROUND: A Metacognitive Training for Schizophrenia patients (MCT) was developed to target the cognitive biases that characterize the illness. Results suggest positive MCT effects encompassing several aspects of psychopathology and subjective well-being. There are still open questions concerning the effect on different cognitive biases and the interplay between them and both psychopathology and neurocognition. Specifically, the bias against disconfirmatory evidence (BADE) has never been tested in previous trials on MCT. In this study we evaluated the feasibility of MCT combined with a cognitive remediation therapy (CACR) in schizophrenia and its effect on BADE. Moreover, we investigated the relationships between BADE and both neuropsychology and psychopathology, taking into account mutual influences on the degree of improvement. METHODS: Fifty-seven schizophrenia outpatients were randomly assigned to CACR + control group or MCT+CACR and assessed at baseline and after treatment for psychopathology, neurocognition and BADE. RESULTS: After MCT+CACR patients showed significantly greater improvements on BADE. Although BADE baseline performances correlated with several cognitive domains, no association was found between BADE improvement and neurocognitive nor psychopathological measures. CONCLUSIONS: This study enlightened for the first time the efficacy of MCT+CACR on BADE in schizophrenia, suggesting the importance to develop a more specific intervention tailored on individual needs of patients.

Chimeric nectin1-poliovirus receptor molecules identify a nectin1 region functional in herpes simplex virus entry.

Human nectin1 (hNectin1), an adhesion molecule belonging to the nectin family of the immunoglobulin superfamily, mediates entry of herpes simplex virus (HSV) into cells. The hNectin1 domain that mediates virus entry into cells and also binds glycoprotein D (gD) has been localized to the first N-terminal V-type domain. The poliovirus receptor (PVR) is a structural homolog to nectins, but it cannot function as an HSV entry receptor. hNectin1-PVR chimeras were constructed to functionally locate the site on hNectin1 involved in HSV entry (HSV entry site). The epitope recognized by monoclonal antibody (MAb) R1.302, which is able to block HSV entry, was also located. The chimeric receptors were designed to preserve the overall structure of the V domain. The HSV entry activity mapped entirely to the hNectin1 portion located between residues 64 and 94 (64-94), likely to encode the C, C', and C" beta-strands and intervening loops. In turn, this site consisted of two portions: one with low-level basal activity for HSV entry (77-94), and one immediately upstream (residues 64 to 76) which greatly enhanced the HSV entry activity of the downstream region. The gD-binding site mapped substantially to the same site, whereas the MAb R1.302 epitope also required a further downstream portion (95-102). The involvement of the 64-76 portion is at difference with previous indirect mapping results that were based on competitive binding studies (C. Krummenacher et al., J. Virol. 74:10863-10872, 2000). The A, A', B, D, E, F, and G beta-strands and intervening loops did not appear to play any role in HSV entry. According to the predicted three-dimensional structure of PVR, the C C' C" site is located peripherally in the V domain and very likely represents an accessible portion at the cell surface.

Novel, soluble isoform of the herpes simplex virus (HSV) receptor nectin1 (or PRR1-HIgR-HveC) modulates positively and negatively susceptibility to HSV infection.

A novel member of the nectin family, nectin1gamma, was molecularly cloned. The cDNA has the same ectodomain as nectin1alpha and nectin1beta, the two known transmembrane isoforms that serve as receptors for herpes simplex virus (HSV) entry into human cell lines (nectin1alpha and nectin1beta, also called PRR1-HveC and HIgR, respectively). The 1.4-kb transcript, which originated by alternative splicing, is expressed in human cell lines, and appears to have a narrow distribution in human tissues. The sequence does not have a hydrophobic anchoring region, and the protein is secreted in the culture medium of cells transfected with the cDNA. Nectin1gamma, purified from culture medium, can compete with membrane-bound nectin1beta and reduce HSV infectivity. The expression of nectin1gamma cDNA in cells resistant to HSV infection and lacking HSV receptors enables HSV to enter the cell, which implies that it is present at the cell surface. Thus, nectin1gamma has the potential both to mediate and to reduce HSV entry into cells.

Differential efficacy of risperidone versus haloperidol in psychopathological subtypes of subchronic schizophrenia.

The aim of this study was to evaluate the efficacy and tolerability of risperidone versus haloperidol in subchronic schizophrenia, using psychopathological subgroups of patients with negative or positive and mixed symptoms to analyse the possible differential efficacy of the drugs. A total of 33 patients diagnosed using DSM-IV criteria entered the 6 week double-blind study with either risperidone or haloperidol 5 mg/day. Twenty-nine patients completed at least 2 weeks of treatment and entered the last observation carried-forward analysis. Both treatments were effective in reducing total scores and positive and negative subscale scores on the Positive and Negative Scale for Schizophrenia (PANSS), with a significantly better extrapyramidal profile in the risperidone-treated group. When analysis was repeated in each treatment group by psychopathological subtype (negative vs positive-mixed subgroups based on the PANSS composite index), risperidone was significantly superior to haloperidol in the intention to treat analysis in the negative subgroup. Repeated measures multivariate analysis of variance showed a significantly greater improvement in the PANSS negative subscale scores of risperidone-treated patients in the negative subgroup and a significant improvement in the PANSS positive subscale scores in both psychopathological subtypes. Haloperidol was significantly effective only in reducing positive symptoms in the positive subtype. Our results indicate that risperidone may be proposed for first-line treatment of subchronic schizophrenia, in particular the negative subtype. Copyright 2001 John Wiley & Sons, Ltd.

Higher macrophage inflammatory protein (MIP)-1alpha and MIP-1beta levels from CD8+ T cells are associated with asymptomatic HIV-1 infection.

To test the hypothesis that beta-chemokine levels may be relevant to the control of HIV in vivo, we compared RANTES, MIP-1alpha, and MIP-1beta production from purified CD8(+) T cells from 81 HIV-infected subjects and from 28 uninfected donors. Asymptomatic HIV(+) subjects produced significantly higher levels of MIP-1alpha and MIP-1beta, but not RANTES, than uninfected donors or patients that progressed to AIDS. In contrast, beta chemokines in plasma were either nondetectable or showed no correlation with clinical status. The high beta-chemokine-mediated anti-HIV activity was against the macrophage tropic isolate HIV-1(BAL), with no demonstrable effect on the replication of the T-cell tropic HIV-1(IIIB). These findings suggest that constitutive beta-chemokine production may play an important role in the outcome of HIV-1 infection.

The novel receptors that mediate the entry of herpes simplex viruses and animal alphaherpesviruses into cells.

An extended array of cell surface molecules serve as receptors for HSV entry into cells. In addition to the heparan sulphate glycosaminoglycans, which mediate the attachment of virion to cells, HSV requires an entry receptor. The repertoire of entry receptors into human cells includes molecules from three structurally unrelated molecular families. They are (i) HveA (herpesvirus entry mediator A), (ii) members of the nectin family, (iii) 3-O-sulphated heparan sulphate. The molecules have different attributes and play potentially different roles in HSV infection and spread to human tissues. All the human entry receptors interact physically with the virion envelope glycoprotein D (gD). (i) HveA is a member of the TNF-receptor family. It mediates entry of a restricted range of HSV strains. Its expression is restricted to few lineages (e.g. T-lymphocytes). (ii) The human nectin1alpha (HIgR), nectin1delta (PRR1-HveC), and the nectin2alpha (PRR2alpha-HveB) and nectin2delta (PRR2delta) belong to the immunoglobulin superfamily. They are homologues of the poliovirus receptor (CD155), with which they share the overall structure of the ectodomain. The human nectin1alpha-delta are broadly expressed in cell lines of different lineages, are expressed in human tissue targets of HSV infection, serve as receptors for all HSV-1 and HSV-2 strains tested and mediate entry not only of free virions, but also cell-to-cell spread of virus. (iii) The 3-O-sulphated heparan sulphate is expressed in some selected human cell lines (e.g. endothelial and mast cells) and human tissues, and mediates entry of HSV-1, but not HSV-2. The human nectin2alpha and nectin2delta serve as receptors for a narrow range of viruses. A characteristic of the human nectin1alpha-delta is the promiscuous species non-specific receptor activity towards the animal alphaherpesviruses, pseudorabies virus (PrV) and bovine herpesvirus 1 (BHV-1). By contrast with the human nectin1delta, its murine homologue (mNectin1delta) does not bind gD at detectable level, yet it mediates entry of HSV, as well as of PrV and BHV-1. This provides the first example of a mediator of HSV entry independent of a detectable interaction with gD.

The murine homolog of human Nectin1delta serves as a species nonspecific mediator for entry of human and animal alpha herpesviruses in a pathway independent of a detectable binding to gD.

The full-length cDNA of the murine homolog of human nectin1delta (mNectin1delta), also known as human poliovirus receptor related 1 (PRR1) or herpesvirus entry mediator C, was cloned and showed a >90% identity with its human counterpart. mNectin1delta is expressed in some murine cell lines, exemplified by NIH 3T3 and L cells, and in murine tissues. It mediates entry of an extended range of herpes simplex virus (HSV) strains, porcine pseudorabies virus (PrV), and bovine herpesvirus 1. A soluble form of the mediator blocked infectivity in mNectin1delta and human nectin1delta (hNectin1delta)-expressing cells, suggesting a physical interaction of the mediator with virions. The higher concentrations of soluble mNectin1 required to block infectivity relative to soluble hNectin1 suggest that the target of the two molecules is not identical. Entry of HSV, but not PrV, was blocked by soluble mNectin1delta in NIH 3T3 and L cells. Two features were unexpected. First, soluble mNectin1delta failed to physically interact with HSV glycoprotein D (gD) at a detectable level, although it interacted physically with virions. Second, coexpression of mNectin1delta and HSV gD did not restrict HSV or PrV infection, whereas coexpression of hNectin and gD did restrict infection, suggesting that mNectin1delta fails to be sequestered by HSV gD. We conclude that mNectin1delta serves as a species-nonspecific mediator for entry of the human and animal alphaherpesviruses. This activity, at least for HSV, is independent of a detectable binding to gD.

Cell-to-cell spread of wild-type herpes simplex virus type 1, but not of syncytial strains, is mediated by the immunoglobulin-like receptors that mediate virion entry, nectin1 (PRR1/HveC/HIgR) and nectin2 (PRR2/HveB).

The immunoglobulin-like receptors that mediate entry of herpes simplex virus type 1 (HSV-1) into human cells were found to mediate the direct cell-to-cell spread of wild-type virus. The receptors here designated Nectin1alpha and -delta and Nectin2alpha were originally designated HIgR, PRR1/HveC, and PRR2alpha/HveB, respectively. We report the following. (i) Wild-type HSV-1 spreads from cell to cell in J cells expressing nectin1alpha or nectin1delta but not in parental J cells that are devoid of entry receptors. A monoclonal antibody to nectin1, which blocks entry, also blocked cell-to-cell spread in nectin1-expressing J cells. Moreover, wild-type virus did not spread from a receptor-positive to a receptor-negative cell. (ii) The antibody to nectin1 blocked transmission of wild-type virus in a number of human cell lines, with varying efficiencies, suggesting that nectin1 is the principal mediator of wild-type virus spread in a variety of human cell lines. (iii) Nectin1 did not mediate cell fusion induced by the syncytial strains HSV-1(MP) and HFEM-syn. (iv) Nectin2alpha could serve as a receptor for spread of a mutant virus carrying the L25P substitution in glycoprotein D, but not of wild-type virus, in agreement with its ability to mediate entry of the mutant but not of wild-type virus.

Nectin2alpha (PRR2alpha or HveB) and nectin2delta are low-efficiency mediators for entry of herpes simplex virus mutants carrying the Leu25Pro substitution in glycoprotein D.

The receptors for entry of herpes simplex viruses 1 and 2 (HSV-1 and -2), widely expressed in human cell lines, are members of a subset of the immunoglobulin superfamily exemplified by herpesvirus entry mediator C (HveC) and the herpesvirus immunoglobulin-like receptor (HIgR). This report focuses on two members of this subset, herpesvirus entry mediator B (HveB), recently designated nectin2/PRR2alpha, and its splice variant isoform, nectin2/PRR2delta. Nectin2alpha and -delta share the ectodomain but differ in the transmembrane and cytoplasmic regions. HveB was reported to enable entry of HSV-1 carrying mutations in glycoprotein D (gD) and of HSV-2, but not of wild-type (wt) HSV-1. We report that (i) both nectin2alpha and -delta served as receptors for the entry of HSV-1 mutant viruses HSV-1(U10) and -(U21) and AP7(r) that carry the Leu25Pro substitution in gD but not for HSV-1 mutants U30 and R5000 that carry the Ser140 or Ala185 substitution in gD. All of these mutants were able to overcome the block to entry mediated by expression of wt gD. (ii) Infection of cells expressing nectin2alpha or -delta required exposure to multiplicities of infection about 100-fold higher than those required to infect cells expressing HveC or HIgR. (iii) gD from HSV-1(U21) bound in vitro soluble forms of nectin2. The association was weaker than that to the soluble form of HveC/HIgR. Binding of wt HSV-1 gD to soluble nectin2 was not detectable. (iv) A major region of nectin2 functional in virus entry mapped to the V domain, located at the N terminus.

Spontaneous and antigen-induced production of HIV-inhibitory beta-chemokines are associated with AIDS-free status.

The beta-chemokines RANTES, macrophage inflammatory protein (MIP)-1alpha, and MIP-1beta suppress infection by macrophage-tropic strains of HIV and simian immunodeficiency virus (SIV) by binding and down-regulating the viral coreceptor, CCR5. Accordingly, we have examined whether higher levels of CCR5 ligands are associated with a more favorable clinical status in AIDS. A cross-sectional study of 100 subjects enrolled in the Multicenter AIDS Cohort Study at the Baltimore site was conducted to measure chemokine production and lymphocyte proliferation by peripheral blood mononuclear cells (PBMC). Statistical analyses of the data revealed that the production of HIV-suppressive beta-chemokines by HIV antigen-stimulated PBMC was significantly higher in HIV-positive subjects without AIDS compared with subjects with clinical AIDS. Increased chemokine production was also correlated with higher proliferative responses to HIV antigens. Both parameters were significantly lower in the AIDS versus non-AIDS group. Notably, significantly higher levels of MIP-1alpha were also observed with unstimulated PBMC from seronegative subjects at risk for HIV infection released as compared with seropositive and non-Multicenter AIDS Cohort Study seronegative subjects. The association of chemokine production with antigen-induced proliferative responses, more favorable clinical status in HIV infection, as well as with an uninfected status in subjects at risk for infection suggests a positive role for these molecules in controlling the natural course of HIV infection.

The V domain of herpesvirus Ig-like receptor (HIgR) contains a major functional region in herpes simplex virus-1 entry into cells and interacts physically with the viral glycoprotein D.

The herpesvirus entry mediator C (HveC), previously known as poliovirus receptor-related protein 1 (PRR1), and the herpesvirus Ig-like receptor (HIgR) are the bona fide receptors employed by herpes simplex virus-1 and -2 (HSV-1 and -2) for entry into the human cell lines most frequently used in HSV studies. They share an identical ectodomain made of one V and two C2 domains and differ in transmembrane and cytoplasmic regions. Expression of their mRNA in the human nervous system suggests possible usage of these receptors in humans in the path of neuron infection by HSV. Glycoprotein D (gD) is the virion component that mediates HSV-1 entry into cells by interaction with cellular receptors. We report on the identification of the V domain of HIgR/PRR1 as a major functional region in HSV-1 entry by several approaches. First, the epitope recognized by mAb R1. 302 to HIgR/PRR1, capable of inhibiting infection, was mapped to the V domain. Second, a soluble form of HIgR/PRR1 consisting of the single V domain competed with cell-bound full-length receptor and blocked virion infectivity. Third, the V domain was sufficient to mediate HSV entry, as an engineered form of PRR1 in which the two C2 domains were deleted and the V domain was retained and fused to its transmembrane and cytoplasmic regions was still able to confer susceptibility, although at reduced efficiency relative to full-length receptor. Consistently, transfer of the V domain of HIgR/PRR1 to a functionally inactive structural homologue generated a chimeric receptor with virus-entry activity. Finally, the single V domain was sufficient for in vitro physical interaction with gD. The in vitro binding was specific as it was competed both by antibodies to the receptor and by a mAb to gD with potent neutralizing activity for HSV-1 infectivity.

The ectodomain of a novel member of the immunoglobulin subfamily related to the poliovirus receptor has the attributes of a bona fide receptor for herpes simplex virus types 1 and 2 in human cells.

We report on the functional cloning of a hitherto unknown member of the immunoglobulin (Ig) superfamily selected for its ability to confer susceptibility to herpes simplex virus (HSV) infection on a highly resistant cell line (J1.1-2 cells), derived by exposure of BHKtk- cells to a recombinant HSV-1 expressing tumor necrosis factor alpha (TNF-alpha). The sequence of herpesvirus Ig-like receptor (HIgR) predicts a transmembrane protein with an ectodomain consisting of three cysteine-bracketed domains, one V-like and two C-like. HIgR shares its ectodomain with and appears to be an alternative splice variant of the previously described protein PRR-1 (poliovirus receptor-related protein). Both HIgR and PRR-1 conferred on J1.1-2 cells susceptibility to HSV-1, HSV-2, and bovine herpesvirus 1. The viral ligand of HIgR and PRR-1 is glycoprotein D, a constituent of the virion envelope long known to mediate viral entry into cells through interaction with cellular receptor molecules. Recently, PRR-1, renamed HveC (herpesvirus entry mediator C), and the related PRR-2, renamed HveB, were reported to mediate the entry of HSV-1, HSV-2, and bovine herpesvirus 1, and the homologous poliovirus receptor was reported to mediate the entry of pseudorabies virus (R. J. Geraghty, C. Krummenacher, G. H. Cohen, R. J. Eisenberg, and P. G. Spear, Science 280:1618-1620, 1998; M. S. Warner, R. J. Geraghty, W. M. Martinez, R. I. Montgomery, J. C. Whitbeck, R. Xu, R. J. Eisenberg, G. H. Cohen, and P. G. Spear, Virology 246:179-189, 1998). Here we further show that HIgR or PRR-1 proteins detected by using a monoclonal antibody to PRR-1 are widely distributed among human cell lines susceptible to HSV infection and commonly used for HSV studies. The monoclonal antibody neutralized virion infectivity in cells transfected with HIgR or PRR-1 cDNA, as well as in the human cell lines, indicating a direct interaction of virions with the receptor molecule, and preliminarily mapping this function to the ectodomain of HIgR and PRR-1. Northern blot analysis showed that HIgR or PRR-1 mRNAs were expressed in human tissues, with the highest expression being detected in nervous system samples. HIgR adds a novel member to the cluster of Ig superfamily members able to mediate the entry of alphaherpesviruses into cells. The wide distribution of HIgR or PRR-1 proteins among human cell lines susceptible to HSV infection, coupled with the neutralizing activity of the antibody in the same cells, provides direct demonstration of the actual use of this cluster of molecules as HSV-1 and HSV-2 entry receptors in human cell lines. The high level of expression in samples from nervous system makes the use of these proteins in human tissues very likely. This cluster of molecules may therefore be considered to constitute bona fide receptors for HSV-1 and HSV-2.

The leukotriene B4 receptor functions as a novel type of coreceptor mediating entry of primary HIV-1 isolates into CD4-positive cells.

The recently cloned human chemoattractant receptor-like (CMKRL)1, which is expressed in vivo in CD4-positive immune cells, has structural homology with the two chemokine receptors C-C chemokine receptor (CCR)5 and C-X-C chemokine receptor (CXCR)4, which serve as the major coreceptors necessary for fusion of the HIV-1 envelope with target cells. In view of the structural similarity, CMKRL1 was tested for its possible function as another HIV-1 coreceptor after stable expression in murine fibroblasts bearing the human CD4 receptor. The cells were infected with 10 primary clinical isolates of HIV-1, and entry was monitored by semiquantitative PCR of viral DNA. The efficiency of the entry was compared with the entry taking place in CD4-positive cells expressing either CCR5 or CXCR4. Seven of the isolates used CMKRL1 for viral entry; they were mainly of the syncytium-inducing phenotype and also used CXCR4. Entry efficiency was higher with CMKRL1 than with CXCR4 for more than half of these isolates. Three of the ten isolates did not use CMKRL1; instead, entry was mediated by both CCR5 and CXCR4. The experiments thus indicate that CMKRL1 functions as a coreceptor for the entry of HIV-1 into CD4-positive cells. In the course of this study, leukotriene B4 was shown to be the natural ligand for this receptor (now designated BLTR), which therefore represents a novel type of HIV-1 coreceptor along with the previously identified chemokine receptors. BLTR belongs to the same general chemoattractant receptor family as the chemokine receptors but is structurally more distant from them than are any of the previously described HIV-1 coreceptors.

Beta-chemokines and protection from HIV type 1 disease.

A small revolution has occurred in the field of AIDS research. A number of chemokines, most of which belong to the CC or beta family, were found by us and others to inhibit HIV infection potently and specifically. The mechanism of such inhibition was shown to be at the level of receptor binding, as these chemokines are binding to receptors that mediate HIV infection. Therefore, chemokines effectively block entry of HIV. Although chemokines have a natural function as chemoattractants, it is intriguing to think that in crossing their path with the virus, they constitute the first example of a naturally occurring soluble molecule, other than antibodies, that can specifically prevent infection. Thus, chemokines could play a role in protective immunity against HIV infection together with other classic correlates, such as neutralizing antibodies and cytotoxic T cells, and some clinical studies suggest that this is indeed the case. Here we review and analyze some of the basic and clinical science that led to the elucidation of the role of chemokines and their receptor in protection from HIV infection.

C-C chemokine RANTES and HIV long terminal repeat-driven gene expression.

The C-C chemokines RANTES, MIP-1alpha, and MIP-1beta have been characterized as constituents of an HIV- and SIV-suppressive factor released by CD8+ cells. Furthermore, it has been demonstrated that chemokine receptors cooperate in HIV entry. However, these proteins are also known to have an effect on multiple intracellular signaling cascades that may affect the process of transcription. In the present study we demonstrate that treatment of CD4+ T cells with these chemokines or with cell supernatants from HTLV-I-immortalized CD8+ T cells results in significant reduction in the abundance of HIV-1-specific RNA as analyzed by Northern blot hybridization. To examine the possibility that such suppressive factors may inhibit HIV RNA transcription, we studied the effect of RANTES, the most effective HIV-suppressive chemokine, on basal and Tat-induced HIV-directed LTR expression of a reporter gene. Neither recombinant RANTES nor conditioned medium from CD8+ cells significantly altered HIV-1 LTR-directed chloramphenicol acetyltransferase expression in either transiently or stably transfected CD4+ T cell lines, either in the presence or in the absence of Tat. These results suggest that C-C chemokines do not inhibit viral RNA transcription.