A case of primary HIV-1 infection

Effects of oleic acid or triolein on lymphatic recovery of docosahexaenoic acid (DHA) given as an ethyl ester were examined in rats with cannulated thoracic ducts. Lymphatic recovery of ethyl DHA given with oleic acid or triolein was significantly higher than in rats given ethyl DHA alone. DHA distributed almost exclusively at the 1- and 3-position of triglyceride in lymph collected at 0-3 h after the administration, when it was given with oleic acid or triolein. A small part of DHA distributed at the 2-position when ethyl DHA was the sole fatty acid given. Oleic acid given as free acid or triolein with ethyl DHA was a major fatty acid at the 2-position. Intramolecular distribution of DHA and oleic acid in lymph triglyceride was similar when ethyl DHA was given with oleic acid or triolein.     

The duration of viral suppression during protease inhibitor therapy for HIV-1 infection is predicted by plasma HIV-1 RNA at the nadir

OBJECTIVE: To determine markers that are associated with the durability of virologic response to therapy with HIV protease inhibitors in HIV-infected individuals. DESIGN: This study encompassed two retrospective analyses of the duration of virologic response to protease inhibitor therapy. The first analysis included 29 patients receiving either monotherapy or combination therapy with the protease inhibitor ritonavir whose plasma HIV RNA levels rebounded from the point of greatest decline with mutations associated with resistance to ritonavir. The second analysis included a cohort of 102 patients who initially responded to randomized treatment with either monotherapy with ritonavir or combination therapy with ritonavir and zidovudine. METHODS: Durability of response was defined as the time from the initiation of therapy to the point at which plasma HIV RNA displayed a sustained increase of at least 0.6 log10 copies/ml from the nadir value. In the first analysis, durability of response was analyzed with respect to baseline HIV RNA, HIV RNA at the nadir, and the drop in HIV RNA from baseline to the nadir. In the second analysis, time to rebound was examined using Kaplan-Meier analysis, stratifying by either baseline HIV RNA or HIV RNA at the nadir. RESULTS: In both analyses, the durability of response was not highly associated with either baseline RNA or the magnitude of RNA decline from baseline. Instead, a strong relationship was observed between the durability of response and the nadir plasma HIV-1 RNA value (P < 0.01). The nadir in viral load was generally reached after 12 weeks of randomized therapy. CONCLUSIONS: Viral RNA determinations at intermediate timepoints may be prognostic of impending virologic failure of protease inhibitor therapy. Therapeutic strategies that allow intensification of initial antiretroviral regimens in the subset of patients with incomplete virological response before the emergence of high level resistance should be investigated.     

Peptide inhibitors of HIV-1 protease and viral infection of peripheral blood lymphocytes based on HIV-1 Vif

We recently reported that HIV-1 Vif (virion infectivity factor) inhibits HIV-1 protease in vitro and in bacteria, suggesting that it may serve as the basis for the design of new protease inhibitors and treatment for HIV-1 infection. To evaluate this possibility, we synthesized peptide derivatives from the region of Vif, which inhibits protease, and tested their activity on protease. In an assay of cleavage of virion-like particles composed of HIV-1 Gag precursor polyprotein, full-length recombinant Vif, and a peptide consisting of residues 21-65 of Vif, but not a control peptide or BSA, inhibited protease activity. Vif21-65 blocked protease at a molar ratio of two to one. We then tested this peptide and a smaller peptide, Vif41-65, for their effects on HIV-1 infection of peripheral blood lymphocytes. Both Vif peptides inhibited virus expression below the limit of detection, but control peptides had no effect. To investigate its site of action, Vif21-65 was tested for its effect on Gag cleavage by protease during HIV-1 infection. We found that commensurate with its reduction of virus expression, Vif21-65 inhibited the cleavage of the polyprotein p55 to mature p24. These results are similar to those obtained by using Ro 31-8959, a protease inhibitor in clinical use. We conclude that Vif-derived peptides inhibit protease during HIV-1 infection and may be useful for the development of new protease inhibitors.     

Severe primary HIV-1 infection among black persons in Barbados

The purpose of this long-term follow-up was (1) to investigate disc changes in the olisthetic segment in patients treated conservatively, (2) to compare disc changes above the slipped vertebra in conservatively treated patients with those in operatively treated patients, and (3) to establish possible relations of disc changes to the degree of the slip and to subjective back pain symptoms of the patients. The subjects were 227 patients with isthmic L5 olisthesis diagnosed under 20 years of age (mean 13.8 years) with a mean follow-up of 15.4 (range 5-30) years. Of these, 145 patients had been treated with segmental fusion and 82 had been treated conservatively. At follow-up, standing anteroposterior and lateral radiographs as well as flexion/extension views of the lumbar spine were taken. Disc degeneration was graded semiquantitatively: 0 = normal disc height, 1 = decrease of disc height < 50%, 2 = decrease > or = 50%, and 3 = obliteration of the disc. In the conservatively treated patients degeneration of the olisthetic disc was distributed by grade as follows: O: n = 38, 1: n = 24, 2: n = 14, 3: n = 6. No motion at all was observed in the olisthetic segment in 40 patients (48%) with a mean slip of 30%, segmental motion of 4 degrees-18 degrees was found in 42 patients with a mean slip of 14%. There was a statistically significant association of the degree of slip to the severity of disc degeneration and non-mobility of the segment. Grade 1 degeneration of the L4/5 disc occurred in 25.6% of the conservatively treated patients and in 32% of 48 patients treated with L5-S1 fusion. This correlated with the severity of the slip, but not with pain symptoms or pathologic segmental mobility at the time of follow-up. Out of 84 patients with L4-S1 fusion, in 17% grade 1 degeneration of the L3/4 disc was observed, and 3 out of 13 patients (23%) with L3-S1 fusion had grade 1 degeneration of the disc above the fusion. The disc changes had no correlation with subjective pain symptoms. It is concluded that the natural course of isthmic spondylolisthesis is associated with disc degeneration and spontaneous stabilization of the olisthetic segment. Fusion operations do not significantly increase the rate of disc degeneration in the adjacent disc above the fusion after a mean postoperative follow-up of 13.8 years. No correlation between the number of degenerated discs or the degree of degeneration and subjective low back pain symptoms was found.     

Genotypic and phenotypic characterization of HIV-1 patients with primary infection

Better characterization of human immunodeficiency virus-type 1 (HIV-1) in patients with primary infection has important implications for the development of an acquired immunodeficiency syndrome (AIDS) vaccine because vaccine strategies should target viral isolates with the properties of transmitted viruses. In five HIV-1 seroconverters, the viral phenotype was found to be uniformly macrophage-tropic and non-syncytium-inducing. Furthermore, the viruses were genotypically homogeneous within each patient, but a common signature sequence was not discernible among transmitted viruses. In the two cases where the sexual partners were also studied, the sequences of the transmitted viruses matched best with minor variants in the blood of the transmitters. There was also a stronger pressure to conserve sequences in gp120 than in gp41, nef, and p17, suggesting that a selective mechanism is involved in transmission.     

Pediatric HIV-1 infection

Although there is optimism that with the prospective identification and treatment of HIV-1-infected pregnant women the incidence of pediatric infection can be diminished, currently the number of HIV-1-infected children continues to rise. Improvements in early diagnosis provide the potential for early intervention, and the advent of more potent antiretroviral agents provides the hope of better treatment strategies to slow disease progression in HIV-1-infected children.     

Cultured blood dendritic cells retain HIV-1 antigen-presenting capacity for memory CTL during progressive HIV-1 infection

Dendritic cells (DC) are potent APC that may be involved in the pathogenesis of HIV-1 infection. We studied the APC function of DC from HIV-1-infected subjects that were derived from monocyte-depleted PBMC by culture in human IL-4 and human granulocyte-macrophage CSF. The cultured cells from the HIV-1-infected subjects had similar morphology and phenotype of mature DC (CD80 = 41 +/- 8%, CD86 = 77 +/- 5%, CD40 = 87 +/- 6%, CD1a = 1 +/- 1%) to DC cultured from seronegative subjects. The yield of these DC was lower than from HIV-1-seronegative subjects (4 +/- 0% vs 11 +/- 2%, p < 0.01), and the lower DC yields correlated with lower numbers of blood CD4+ T cells (r = 0.60, p < 0.01) and higher plasma viral load (r = -0.49, p < 0.01). DC from HIV-1-infected subjects were infected with recombinant vaccinia virus vectors expressing Gag, Pol, and Env and were able to stimulate equal or higher levels of MHC class I-restricted, anti-HIV-1 memory CTL (CTLm) than were similarly treated, autologous B lymphocyte cell lines. DC pulsed with peptides representing HIV-1 CTL epitopes stimulated higher levels of anti-HIV-1 CTLm responses than did DC infected with the vaccinia virus-HIV-1 constructs. Allogeneic, MHC class I-matched DC also stimulated anti-HIV-1 CTLm activity in cells from HIV-1-infected subjects. DC from early and late stages of HIV-1 infection had a similar ability to activate CTLm specific for targets expressing either HIV-1 genes via vaccinia virus vectors or HIV-1 immunodominant synthetic peptides. However, DC from either early or late stages of HIV-1 infection could not overcome the defect in anti-HIV-1 CTLm response in advanced infection.     

Increased plasma levels of the C-C chemokine RANTES in patients with primary HIV-1 infection

To investigate the role played by chemokines in the natural history of human immunodeficiency virus (HIV) infection, we measured the plasma levels of RANTES. MIP-1 alpha and MIP-1 beta in a cohort of patients with primary HIV-1 infection (PHI) followed longitudinally. The cohort included 17 patients with well-documented history of acute HIV syndrome within two months of the first observation. The mean plasma concentration of RANTES, but not that of MIP-1 alpha or MIP-1 beta, was significantly higher in patients with PHI (192.3 ng/ml) than in five HIV-seronegative controls (8.0 ng/ml) studied during the same time period. Treatment of blood with a cocktail of drugs preventing platelet activation, followed by high-speed centrifugation, reduced the levels of RANTES by approximately 2 logs both in patients and in controls, indicating that the bulk of RANTES was released by platelets, which are known to store this chemokine in their alpha-granules, in the immediate aftermath of blood drawing. No correlation was seen between the levels of RANTES and the number of HIV genome equivalents in plasma. These data suggest that large amounts of pre-formed RANTES are stored in platelets and, possibly, in other blood cells during the early phases of HIV infection. The possible role of this HIV-suppressive chemokine in the control of viral replication during PHI remains to be established.     

Cell-associated viral RNA expression during acute infection with HIV type 1

The mechanism of decline in viremia following acute infection with HIV is unknown. To characterize this process virologically, the expression of viral RNAs was analyzed in samples of peripheral blood mononuclear cells (PBMCs) from a patient who experienced a 100-fold decline in plasma viremia over a 13-day period prior to the initiation of antiretroviral therapy. Cell-associated viral RNA declined in association with the decline in plasma virus. During the initial 7 days of observation, plasma viremia declined more than 10-fold with no change in the ratio of unspliced to multiply spliced mRNAs. The efficiency of viral gene expression did not decline during the study period and varied from 380 to 2800 unspliced RNA copies per productively infected cell. Together, these data indicate no change in the relative proportion of cells in late- and early-stage gene expression during the initial decline and provide evidence against shortening of the viral replication cycle by immune surveillance. However, the prevalence of productively infected cells declined markedly during the 13 days of observation, from 1 in 250 to 1 in 25,000 PBMCs. These data are compatible with depletion of available target cells during the initial decline in viremia. As the level of plasma virus stabilized after 8 days of observation, the ratio of unspliced to multiply spliced mRNAs rose; this rise was due to a relatively greater decline in multiply spliced mRNA. These data suggest the possible onset of a blockade to new infection events (for example, by neutralizing antibody or chemokines), causing an increase in the relative proportion of cells in late-stage gene expression. They may also be explained, however, by the persistence of cell-associated virions together with the near disappearance of productively infected cells from the circulation.     

Long-term survivors of HIV-1 infection

The clinical course and outcome of HIV-1 infection are highly variable. A full spectrum of pathology has been observed, from rapid progression to AIDS within months of HIV-1 seroconversion, to asymptomatic survival for more than a decade. This phenomenon probably reflects the multiphasic and multifactorial nature of the virus-host interactions. Obviously, interest in the extremes now recognized in HIV-1 disease progression is growing, with the hope that mechanisms of protection may be found.     

Plasma levels of soluble CD30, tumour necrosis factor (TNF)-alpha and TNF receptors during primary HIV-1 infection: correlation with HIV-1 RNA and the clinical outcome

OBJECTIVES: The immunological and virological events associated with primary HIV-1 infection have a major impact on the course of HIV-1 disease, and the identification of early predictors during primary HIV infection is critical for the therapeutic strategy. DESIGN AND METHODS: Eighteen consecutive patients with primary HIV infection were followed for a median of 398 days. Clinical status, CD4+ T-cell counts, and plasma samples were obtained weekly from enrollment until week 6, then at weeks 12, 24 and 52, and every 6 months thereafter. Seroconversion was assessed by anti-HIV-1/2 antibodies and Western blot analysis. HIV-1 RNA in plasma was quantified by Amplicor HIV Monitor test. Samples were assayed for immune complex-dissociated p24 antigen, tumour necrosis factor (TNF)-alpha, soluble TNF receptor (sTNFR)-1, sTNFR-II, sCD30 and sCD8 by enzyme immunoassays. Outcome was defined as entering clinical category B or C according to the Centers for Disease Control and Prevention criteria. As a control group, we included 23 HIV-1-negative healthy blood donors. RESULTS: Plasma levels of sCD30, TNF-alpha and sTNFR were significantly higher in HIV-1-infected patients than in controls, and were positively correlated with each other and with values of HIV-1 RNA. Patients who developed an outcome (n = 4) had significantly higher levels of sCD30, TNF-alpha and sTNFR compared with those who did not. Multivariate logistic regression analysis showed that sCD30 and TNF-alpha were the best predictors of outcome independently of CD4+ T-cell counts. CONCLUSIONS: During primary HIV infection, a persistent immune activation may be associated with a poor clinical outcome. The identification of sCD30 and TNF-alpha levels in plasma as early predictors of outcome in primary HIV infection, may direct the implementation of early therapeutic strategies in patients with elevated risk of disease progression.     

Influence of delayed viral production on viral dynamics in HIV-1 infected patients

We present and analyze a model for the interaction of human immunodeficiency virus type 1 (HIV-1) with target cells that includes a time delay between initial infection and the formation of productively infected cells. Assuming that the variation among cells with respect to this 'intracellular' delay can be approximated by a gamma distribution, a high flexible distribution that can mimic a variety of biologically plausible delays, we provide analytical solutions for the expected decline in plasma virus concentration after the initiation of antiretroviral therapy with one or more protease inhibitors. We then use the model to investigate whether the parameters that characterize viral dynamics can be identified from biological data. Using non-linear least-squares regression to fit the model to simulated data in which the delays conform to a gamma distribution, we show that good estimates for free viral clearance rates, infected cell death rates, and parameters characterizing the gamma distribution can be obtained. For simulated data sets in which the delays were generated using other biologically plausible distributions, reasonably good estimates for viral clearance rates, infected cell death rates, and mean delay times can be obtained using the gamma-delay model. For simulated data sets that include added simulated noise, viral clearance rate estimates are not as reliable. If the mean intracellular delay is known, however, we show that reasonable estimates for the viral clearance rate can be obtained by taking the harmonic mean of viral clearance rate estimates from a group of patients. These results demonstrate that it is possible to incorporate distributed intracellular delays into existing models for HIV dynamics and to use these refined models to estimate the half-life of free virus from data on the decline in HIV-1 RNA following treatment.     

Accumulation of unintegrated circular viral DNA in monocytes and growth-arrested T cells following infection with HIV-1

Cytocidal retrovirus infection is characterized by rapid accumulation of unintegrated viral DNA forms. These are thought to be generated by multiple rounds of reinfection and have been suggested to play a central role in cytopathogenesis. Here we have reviewed the work done in this area with HIV-1, mostly using acutely and chronically infected T cell and monocytic cell lines and in some cases T cells blocked at S phase of the cell cycle by aphidicolin treatment. To these studies, we have compared our findings with HIV-1 infected primary peripheral blood monocyte-derived macrophages and untreated and growth-arrested MT-2 cells, two biologically disparate cell populations. Using 1- and 2-long terminal repeat (LTR) circular forms as indicators of unintegrated viral DNA, we found similar rapid accumulation in both untreated and growth-arrested MT-2 cells. In contrast, we found much lower levels in monocyte/macrophages. Our findings suggest that accumulation of unintegrated viral DNA does not require virus production and reinfection in growth-arrested T cells. The significantly lower levels found in monocyte/macrophages may reflect superinfection resistance, allowing the maintenance of a persistent infection.     

Mutual interactions between HIV-1 and cytokines in adherent cells during acute infection

Intracerebroventricular (i.c.v.) infusions of angiotensin II (AII) reliably induced c-fos expression in the supraoptic (SON) and paraventricular (PVN) nuclei, as well as other areas of the basal forebrain including the OVLT, subfornical organ (SFO), and bed nucleus (BNST). Double-labelling showed that AII-induced c-fos was observed in both vasopressin (AVP-) and oxytocin (OXY)-containing neurons of the SON and PVN in male rats. Allowing rats to drink water after AII infusions suppressed c-fos expression both AVP- and OXY-stained magnocellular neurons. Intragastric infusions of water were also effective, showing that oro-pharyngeal stimuli were not critical. Maximal suppression occurred in rats in whom water had been infused intragastrically about 5 min before i.c.v. AII infusions, suggesting that changes in osmolarity were responsible. i.c.v. AII also induced c-fos expression in a number of brainstem structures, including the solitary nucleus (NTS), lateral parabrachial nucleus (LPBN), locus coeruleus (LC), and the area postrema (AP). These results indicate that AVP and OXY-containing neurons in the magnocellular parts of the SON and PVN alter their immediate-early gene response to AII after water intake, and that this does not depend upon oro-pharyngeal factors. Furthermore, AII can induce c-fos expression in a number of brainstem nuclei associated with autonomic function, and these do not respond to water intake.