HIV causes AIDS

Comparing methods to detect cellular proteins on the surface of HIV-1 virions

The surface of HIV-1 is embedded with numerous host-derived proteins. Characterizing these proteins can enhance knowledge of virus biology and potentially identify novel therapeutic targets. As many of these proteins are present in low abundance on virion surfaces, their identification can be hindered by inherent variables in the methods employed to detect them, including their varying assay sensitivities, sample processing, quantitative capacity, and experimental reproducibility. Here, we have compared the quantification of virion-incorporated proteins using conventional virus immunocapture assays and western blotting, alongside an emerging technique called flow virometry (FV). Using four different pseudovirus models that each express a human protein of interest (CD14, CD38, CD59 and CD162), we compared four experimental techniques for their ability to reliably quantify the incorporation of those four proteins onto virion surfaces. Our results shed light on the advantages and caveats of each technique for detecting virion-incorporated proteins and highlight the breadth in quantification for each technique under different experimental conditions. Protein detection with (FV) provided distinct advantages as it enabled highly reproducible quantifications, had the lowest sample requirements and reagent costs, and minimal hands-on experimental time. We additionally highlight some important considerations in experimental design when studying virion-incorporated proteins, such as the effect of different antibody clones, assay incubation times, and contributions of extracellular vesicles. Most importantly, our data illustrate the importance of using a combination of orthogonal approaches to detect virus-associated proteins, to enable reliable and reproducible quantification that accounts for individual assay biases.

Immunologically effective biomaterials-enhanced vaccines against infection of pathogenic microorganisms

Infectious diseases are severe public health events that threaten global health. Prophylactic vaccines have been considered as the most effective strategy to train the immune system to recognize and clear pathogenic infections. However, the existing vaccines against infectious diseases have several limitations, such as difficulties in mass manufacturing and storage, weak immunogenicity, and low efficiency of available adjuvants. Biomaterials, especially functional polymers, are expected to break through these bottlenecks based on the advantages of biocompatibility, degradability, controlled synthesis, easy modification, precise targeting, and immune modulation, which are excellent carriers and adjuvants of vaccines. This review mainly summarizes the application of immunologically effective polymers-enhanced vaccines against viruses- and bacteria-related infectious diseases and predicted their potential improvements.

Underweight and Its Predictors Among Patients on Anti Retroviral Therapy at Selected Health Facilities of Addis Ababa, Ethiopia, 2020

Objective

The study aimed at assessing the prevalence of underweight and its predictors in patients on ART, in health facilities of Addis Ababa, Ethiopia, 2020.

Methods

A multi-center-based cross-sectional study was conducted among 319 patients on ART selected on the basis of stratified sampling method in Addis Ababa from July 01 to August 30, 2020. An interviewer-administered structured questionnaire was used for collection of the data, after which informed consent was obtained from all the included participants. Descriptive statistics for the summarization of the data was used. Binary (Bivariate and multivariate) logistics regression was applied for the identification of predictors of underweight and its strength of association with their respective 95% confidence intervals and less than 5% p-values as statistically significant association.

Findings

The prevalence of underweight among patients on ART was 19.1% (95% CI: 15.0-23.9%), while more than one-tenth (14.4%) of the participants were overweight (95% CI: 10.8-18.8%). A higher level of Educational level, being married, widowed, divorced, a lower family size and poor ART drug adherence level were statistically significantly associated with an increased risk of underweight among patients on ART in the study settings (p<0.05).

Conclusion

Educational level, marital status, family size, and adherence status of the participants were identified predictors of underweight among patients on ART. The lower the educational level, lower family size, being either married, divorced, or widowed, having had of poor ART drug adherence level of the participants, the higher their risk of sustaining underweight. Concerned bodies were suggested to work over the identified determinants of underweight among patients on ART in the study settings.

Novel Applications of Nanotechnology in Controlling HIV and HSV Infections

Infectious diseases have been prevalent since many decades and viral pathogens have caused global health crisis and economic meltdown on a devastating scale. High occurrence of newer viral infections in the recent years, in spite of the progress achieved in the field of pharmaceutical sciences defines the critical need for newer and more effective antiviral therapies and diagnostics. The incidence of multi-drug resistance and adverse effects due to the prolonged use of anti-viral therapy is also a major concern. Nanotechnology offers a cutting edge platform for the development of novel compounds and formulations for biomedical applications. The unique properties of nano-based materials can be attributed to the multi-fold increase in the surface to volume ratio at the nano-scale, tunable surface properties of charge and chemical moieties. Idealistic pharmaceutical properties such as increased bioavailability and retention times, lower toxicity profiles, sustained release formulations, lower dosage forms and most importantly, targeted drug delivery can be achieved through the approach of nanotechnology. The extensively researched nano-based materials are metal and polymeric nanoparticles, dendrimers and micelles, nano-drug delivery vesicles, liposomes and lipid based nanoparticles. In this review article, the impact of nanotechnology on the treatment of Human Immunodeficiency Virus (HIV) and Herpes Simplex Virus (HSV) viral infections during the last decade are outlined.

HIV long-term non-progressors share similar features with simian immunodeficiency virus infection of chimpanzees

HIV-1 infection in human beings has been an outcome of cross-species transmission event of simian immunodeficiency virus from chimpanzees (SIVcpz). Present study reveals differential features of envelope genes representing different categories of HIV-1 disease progression in human beings, namely, rapid progressors (RP), slow progressors (SP) and long-term non-progressors (LTNP) with respect to SIVcpz, based on their amino acid usage patterns. It was evident that SP, LTNP and SIVcpz envelope genes displayed similar patterns of amino acid usage which strongly contrasted with the features exhibited by the envelope genes representing RP category. Robust analysis revealed that selection constraint of human host on SP and LTNP associated envelope genes and chimpanzee host on SIVcpz envelope genes were more severe compared to selection pressure operational on RP associated envelope genes. Evolutionary forces of selection appeared to be comparatively more relaxed on the RP envelope genes in contrast to SP, LTNP and SIVcpz types. Better binding of RP envelope glycoprotein 120 (gp120) compared to envelope gp120 representing SP, LTNP and SIVcpz with host cellular receptor CD4, as inferred employing molecular docking approaches, promises to confer meaningful insights into the event of speedy progression of HIV in rapid progressors. It was interesting to note that envelope glycoprotein exhibited a tendency of hindering proper interaction of host (human/chimpanzee) CD4 and major histocompatibility complex II (MHC II), with a better efficacy in rapid progressors, thus, facilitating highest degrees of immune suppression. Proper identification of the contrasting features might confer a scope to modulate rapid progression of HIV to a long-term non-progressive controlled case, as observed in LTNP and SIVcpz infection, simultaneously aiding therapeutic research against AIDS targeted at drug and vaccine development.Communicated by Ramaswamy H. Sarma.

MicroRNAs and exosomes: key players in HIV pathogenesis

OBJECTIVES

HIV infection is well known to cause impairment of the human immune system, and until recently was a leading cause of death. It has been shown that T lymphocytes are the main targets of HIV. The virus inactivates T lymphocytes by interfering with a wide range of cellular and molecular targets, leading to suppression of the immune system. The objective of this review is to investigate to what extent microRNAs (miRNAs) are involved in HIV pathogenesis.

METHODS

The scientific literature (Pubmed and Google scholar) for the period 1988-2019 was searched.

RESULTS

Mounting evidence has revealed that miRNAs are involved in viral replication and immune response, whether by direct targeting of viral transcripts or through indirect modulation of virus-related host pathways. In addition, exosomes have been found to act as nanoscale carriers involved in HIV pathogenesis. These nanovehicles target their cargos (i.e. DNA, RNA, viral proteins and miRNAs) leading to alteration of the behaviour of recipient cells.

CONCLUSIONS

miRNAs and exosomes are important players in HIV pathogenesis. Additionally, there are potential diagnostic applications of miRNAs as biomarkers in HIV infection.

Roles and potential applications of lncRNAs in HIV infection

Long non-coding RNAs (lncRNAs) are defined as a class of RNA molecules with a length of more than 200 nucleotides that are not translated into protein, and are known to participate in a variety of biological processes. They have recently been implicated as having roles in viral infections, and several research groups have identified that complex interactions exist between lncRNAs and the progression of human immunodeficiency virus (HIV) infection. lncRNAs derived from both the human host and HIV itself are emerging as key regulators of various cellular functions, playing crucial roles in virus-host interactions and viral pathogenesis. This review provides a brief discussion of the roles and associated mechanisms of lncRNAs in HIV infection. Moreover, due to the continued lack of effective HIV vaccines or treatments, we provide an insight into the complex interplay between lncRNAs and HIV and suggest innovative therapeutic strategies for HIV/acquired immunodeficiency syndrome (AIDS). The available data on lncRNAs that have been associated with HIV infection and their potential applications for the treatment of HIV are summarized for the first time, providing a new perspective for the future development of therapeutic strategies.

Comparative evaluation of loop-mediated isothermal amplification (LAMP) assay, GeneXpert MTB/Rif and multiplex PCR for the diagnosis of tubercular lymphadenitis in HIV-infected patients of North India

BACKGROUND

Tubercular lymphadenitis (TBLA) is one of the most common extrapulmonary manifestations of tuberculosis in patients with HIV. With several other pathological conditions presenting as lymphadenitis and lack of consensus regarding a gold standard test, the diagnosis of TBLA remains a challenge for the clinician.

OBJECTIVES

and design: In this study, we have assessed the potential of loop-mediated isothermal amplification (LAMP) test for the diagnosis of TBLA in HIV-infected patients. The study group included samples collected by fine needle aspiration (FNAC) of lymph nodes from 24 HIV-infected patients with TBLA. A composite reference standard was used to identify cases of TBLA based on clinical suspicion, results of cytology, AFB smear, MGIT culture, GeneXpert MTB/RIF, multiplex polymerase chain reaction (MPCR) and subsequently clinical response to antitubercular therapy. These tests were also carried out in 26 control samples of lymph node FNAC from HIV-infected patients with non-tubercular lymphadenitis.

RESULTS

LAMP assay was positive in 19/24 TBLA cases and yielded a sensitivity of 79.17% with 100% specificity. Cytology was suggestive in 18/24 (75%) TBLA cases. GeneXpert MTB/RIF assay correctly identified 16/24 TBLA cases, but the test did show one false positive result reducing its specificity. MPCR had the highest sensitivity of 91.67% as it correctly identified 22/24 cases and showed no false positive result.

CONCLUSION

The current study highlights the potential of LAMP test for the specific diagnosis of tubercular lymphadenitis in FNAC samples from HIV-infected patients, especially when cytology is either non-conclusive or non-available. Though MPCR had a higher sensitivity than LAMP assay, the added advantages of low cost, minimal technical expertise and simplicity of procedure make LAMP assay a suitable diagnostic test in resource-limited settings.

Fullerene-based delivery systems

With the development of new drugs, there have been many attempts to explore innovative delivery routes. Targeted delivery systems are a desired solution designed to overcome the deficiency of routine methods. To transform this idea into reality, a wide range of nanoparticles has been proposed and studied. These nanoparticles should interact well with biological environments and pass through cell membranes to deliver therapeutic molecules. One of the pioneer classes of carbon-based nanoparticles for targeted delivery is the fullerenes. Fullerenes have a unique structure and possess suitable properties for interaction with the cellular environment. This short review concentrates on newly developed fullerene derivatives and their potential as advanced delivery systems for pharmaceutical applications.

Harnessing nanostructured systems for improved treatment and prevention of HIV disease

Combination antiretroviral therapy effectively controls human immunodeficiency virus (HIV) viral replication, delaying the progression to acquired immune deficiency syndrome and improving and extending quality of life of patients. However, the inability of antiretroviral therapeutics to target latent virus and their poor penetration of viral reserve tissues result in the need for continued treatment for the life of the patient. Side effects from long-term antiretroviral use and the development of drug resistance due to patient noncompliance are also continuing problems. Nanostructured systems of antiretroviral therapeutics have the potential to improve targeted delivery to viral reservoirs, reduce drug toxicity, and increase dosing intervals, thereby improving treatment outcomes and enhancing patient adherence. Despite these advantages, very few nanostructured antiretroviral delivery systems have made it to clinical trials due to challenges in preclinical and clinical development. In this context, we review the current challenges in HIV disease management, and the recent progress in leveraging the unique performance of nanostructured systems in therapeutic delivery for improved treatment and prevention of this incurable human disease.

HIV Progression Depends on Codon and Amino Acid Usage Profile of Envelope Protein and Associated Host-Genetic Influence

Acquired immune deficiency syndrome (AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV). Two types of HIV have been characterized: HIV-1 and HIV-2. The present study investigated whether evolutionary selection pressure differs between rapid progressor (RP), slow progressor (SP), and long-term non-progressor (LTNP) of HIV-I infected individuals. An unexpected association between the evolutionary rate of substitution in envelope (env) gene and disease progression is observed. Our present study suggests that env genes of LTNP are subject to unusually strong functional constraint with respect to RP. We also observed that the three categories of env genes i.e., RP, SP, and LTNP, had their own characteristic pattern of amino acid usage and SP and LTNP sequences shared similar patterns of amino acid usage different from RP sequences and evolutionary rate significantly influenced the amino acid usage pattern of the three different types of env gene sequences. It was also noted that the evolutionary rate for the glycosylation sites of LTNP and SP sequences were even significantly less than the RP sequences. Comparative analysis on the influence of human host on the three categories of env genes are well correlated with the rates of disease progression suggesting the adaptive strategies of the viruses for successful residence and infection. Host associated selective constraints appeared most relaxed on the RP sequences and strongest in LTNP sequences. The present study clearly portrays how evolutionary selection pressure differs between three categories of env genes i.e., RP, SP, and LTNP. The env genes, coding for the env glycoproteins, experience severe selection constraints from the host due to their constant exposure to the host immune system. In this perspective it might be suggested that env gene evolution occurs mainly by negative selection with the occurrence of mutation that might not reach fixation in the viral population. This work also confers a deeper insight into the crucial effects of host factors that govern the overall progression of HIV infection.

Defending the boundaries of science: AIDS denialism, peer review and the Medical Hypotheses saga

This paper explores the boundary work undertaken by HIV scientists and activists against the journal Medical Hypotheses over its lack of peer review. Their action was sparked by the publication of an article by Peter Duesberg claiming that HIV does not cause AIDS and that antiretrovirals do more harm than good. Precisely because such 'AIDS denialism' can undermine HIV prevention and treatment interventions, as was demonstrably the case in South Africa under President Mbeki, the episode raised questions about when, in the interests of public health, the boundaries of legitimate scientific debate may be drawn to exclude unreasonable and unscholarly arguments. The paper argues that normative concerns motivated the complaints which resulted in the publisher withdrawing Duesberg's paper and imposing editorial policy changes on Medical Hypotheses. Concerns were raised about the implications for academic freedom of this boundary work in defence of peer review as a core practice in science. The paper concludes, however, that Duesberg's freedom to write what he likes remains intact, but that if he wants his work to carry the imprimatur of science, he now has to subject it to peer review.

AIDS denialism and public health practice

In this paper, we respond to AIDS denialist arguments that HIV does not cause AIDS, that antiretroviral drugs are not useful, and that there is no evidence of large-scale deaths from AIDS, and discuss the key implications of the relationship between AIDS denialism and public health practice. We provide a brief history of how the cause of AIDS was investigated, of how HIV fulfills Koch's postulates and Sir Bradford Hil's criteria for causation, and of the inconsistencies in alternatives offered by denialists. We highlight clinical trials as the standard for assessing efficacy of drugs, rather than anecdotal cases or discussions of mechanism of action, and show the unanimous data demonstrating antiretroviral drug efficacy. We then show how statistics on mortality and indices such as crude death rate, life expectancy, child mortality, and population growth are consistent with the high mortality from AIDS, and expose the weakness of statistics from death notification, quoted by denialists. Last we emphasize that when denialism influences public health practice as in South Africa, the consequences are disastrous. We argue for accountability for the loss of hundreds of thousands of lives, the need to reform public health practice to include standards and accountability, and the particular need for honesty and peer review in situations that impact public health policy.

Emerging nanotechnology approaches for HIV/AIDS treatment and prevention

Currently, there is no cure and no preventive vaccine for HIV/AIDS. Combination antiretroviral therapy has dramatically improved treatment, but it has to be taken for a lifetime, has major side effects and is ineffective in patients in whom the virus develops resistance. Nanotechnology is an emerging multidisciplinary field that is revolutionizing medicine in the 21st century. It has a vast potential to radically advance the treatment and prevention of HIV/AIDS. In this review, we discuss the challenges with the current treatment of the disease and shed light on the remarkable potential of nanotechnology to provide more effective treatment and prevention for HIV/AIDS by advancing antiretroviral therapy, gene therapy, immunotherapy, vaccinology and microbicides.

[Analysis of genetic recombination between human immunodeficiency virus type 1 (HIV-1) and HIV-2]

It is estimated that one million people are dually infected with Human Immunodeficiency Virus type-I (HIV-1) and type-II (HIV-2) in West Africa and parts of India. HIV-1 and HIV-2 use the same receptor and coreceptors for entry into cells, and thus target the same cell populations in the host. Additionally, we first examined whether RNAs from HIV-1 and HIV-2 can be copackaged into the same virion. Therefore these properties suggest that in the dually infected population, it is likely that some cells can be infected by both HIV-1 and HIV-2, thereby providing opportunities for these two viruses to interact with each other. We constructed recombination assay system for measurement recombination frequencies and analyzed recombination rate between HIV-1 and HIV-2. We used modified near-full-length viruses that each contained a green fluorescent protein gene (gfp) with a different inactivating mutation. Thus, a functional gfp could be reconstituted via recombination, which was used to detect copackaging of HIV-1 and HIV-2 RNAs. In this study, approximately 0.2% of infection events generated the GFP phenotype. Therefore, the appearance of the GFP+ phenotype in the current system is approximately 35-fold lower than that between two homologous HIV-1 or HIV-2 viruses. We then mapped the general structures of the recombinant viruses and characterized the recombination junctions by DNA sequencing. We observed several different recombination patterns including those only had crossovers in gfp. The most common hybrid genomes had heterologous LTRs. Although infrequent, crossovers were also identified in the viral sequences. Such chimeric HIV-1 and HIV-2 viruses have yet to be observed in the infected population. It is unclear whether the lack of observed chimeras is due to the divergence between HIV-1 and HIV-2 being too great for such an event to occur, or whether such events could occur but have not yet been observed. Given the number of coinfected people, the potential for interactions between HIV-1 and HIV-2 should not be ignored.

"Is it the cause?"--Robert Koch and viruses in the 21st century

Confirmation that a virus is genuinely the cause of a disease is unexpectedly difficult, especially with new molecular approaches to diagnosis. This paper discusses the problems, which are closely related to the methods used to detect virus (or components of virus), and suggests that longitudinal studies are essential to confirming causation and avoiding unwarranted assumptions.

Genetic recombination between human immunodeficiency virus type 1 (HIV-1) and HIV-2, two distinct human lentiviruses

Human immunodeficiency virus type 1 (HIV-1) and HIV-2 are genetically distinct viruses that each can cause AIDS. Approximately 1 million people are infected with both HIV-1 and HIV-2. Additionally, these two viruses use the same receptor and coreceptors and can therefore infect the same target cell populations. To explore potential genetic interactions, we first examined whether RNAs from HIV-1 and HIV-2 can be copackaged into the same virion. We used modified near-full-length viruses that each contained a green fluorescent protein gene (gfp) with a different inactivating mutation. Thus, a functional gfp could be reconstituted via recombination, which was used to detect the copackaging of HIV-1 and HIV-2 RNAs. The GFP-positive (GFP(+)) phenotype was detected in approximately 0.2% of the infection events, which was 35-fold lower than the intrasubtype HIV-1 rates. We isolated and characterized 54 GFP(+) single-cell clones and determined that all of them contained proviruses with reconstituted gfp. We then mapped the general structures of the recombinant viruses and characterized the recombination junctions by DNA sequencing. We observed several different recombination patterns, including those that had crossovers only in gfp. The most common hybrid genomes had heterologous long terminal repeats. Although infrequent, crossovers in the viral sequences were also identified. Taken together, our study demonstrates that HIV-1 and HIV-2 can recombine, albeit at low frequencies. These observations indicate that multiple factors are likely to restrict the generation of viable hybrid HIV-1 and HIV-2 viruses. However, considering the large coinfected human population and the high viral load in patients, these rare events could provide the basis for the generation of novel human immunodeficiency viruses.

Coassembly and complementation of Gag proteins from HIV-1 and HIV-2, two distinct human pathogens

Approximately one million people in the world are dually infected with both HIV-1 and HIV-2. To identify potential interactions between these two human pathogens, we examined whether HIV-1 and HIV-2 Gag proteins can coassemble and functionally complement each other. We generated HIV-1- and HIV-2-based vectors with mutations in Gag; compared with wild-type vectors, these mutants had drastically decreased viral titers. Coexpression of the mutant HIV-1 and HIV-2 Gag could generate infectious viruses; furthermore, heterologous complementation in certain combinations showed efficiency similar to homologous complementation. Additionally, we used bimolecular fluorescence complementation analysis to directly demonstrate that HIV-1 and HIV-2 Gag can interact and coassemble. Taken together, our results indicate that HIV-1 and HIV-2 Gag polyproteins can coassemble and functionally complement each other during virus replication; to our knowledge, this is the first demonstration of its kind. These studies have important implications for AIDS treatment and the evolution of primate lentiviruses.

HIV type 2 primary isolates induce a lower degree of apoptosis "in vitro" compared with HIV type 1 primary isolates

To determine whether subtypes of HIV-1 and HIV-2 vary in their ability to induce T cell apoptosis in vitro, human peripheral blood mononuclear cells (PBMC) from healthy donors and CEM.NKR-CCR5 cells were infected with a variety of HIV-1 and HIV-2 isolates in vitro. Apoptotic cell levels and chemokine and cytokine production were analyzed. Significant variations in cytopathic effects following in vitro infection with primary isolates of HIV-1 or HIV-2 subtypes were observed in PBMCs. The percent of apoptotic cells from each individual ranged from 2 to 78% after HIV-1 infection and from 0 to 28% after HIV-2 infection (p < 0.01). We did not observe significant differences in the degree of apoptosis induced among cells infected with different HIV-1 group M subtypes or group O virus, nor among cells infected with different HIV-2 isolates. However, HIV-2 induced significantly lower degree of apoptosis overall in PBMC and CEM.NKR-CC5 cells when compared with HIV-1 subtypes (p < 0.0001). No significant differences were observed in the production of chemokines, such as RANTES, MIP-1alpha, and MIP-1beta, and cytokines, such as TNF-alpha and TNF-beta when PBMC cultures were infected with different HIV-1 subtype viruses, or HIV-2 isolates. In conclusion, HIV-2 isolates induced significantly lower levels of T cell apoptosis in both PBMC and CEM.NKR-CCR5 cells than HIV-1 isolates. No differences in T cell apoptosis levels were seen between different subtypes of HIV-1 group M or group O isolates. This is consistent with the mild clinical course of infection with HIV-2 that has been reported relative to that observed with HIV-1.

The chemical bases of the various AIDS epidemics: recreational drugs, anti-viral chemotherapy and malnutrition

In 1981 a new epidemic of about two-dozen heterogeneous diseases began to strike non-randomly growing numbers of male homosexuals and mostly male intravenous drug users in the US and Europe. Assuming immunodeficiency as the common denominator the US Centers for Disease Control (CDC) termed the epidemic, AIDS, for acquired immunodeficiency syndrome. From 1981-1984 leading researchers including those from the CDC proposed that recreational drug use was the cause of AIDS, because of exact correlations and of drug-specific diseases. However, in 1984 US government researchers proposed that a virus, now termed human immunodeficiency virus (HIV), is the cause of the non-random epidemics of the US and Europe but also of a new, sexually random epidemic in Africa. The virus-AIDS hypothesis was instantly accepted, but it is burdened with numerous paradoxes, none of which could be resolved by 2003: Why is there no HIV in most AIDS patients, only antibodies against it? Why would HIV take 10 years from infection to AIDS? Why is AIDS not self-limiting via antiviral immunity? Why is there no vaccine against AIDS? Why is AIDS in the US and Europe not random like other viral epidemics? Why did AIDS not rise and then decline exponentially owing to antiviral immunity like all other viral epidemics? Why is AIDS not contagious? Why would only HIV carriers get AIDS who use either recreational or anti-HIV drugs or are subject to malnutrition? Why is the mortality of HIV-antibody-positives treated with anti-HIV drugs 7-9%, but that of all (mostly untreated) HIV-positives globally is only 1.4%? Here we propose that AIDS is a collection of chemical epidemics, caused by recreational drugs, anti-HIV drugs, and malnutrition. According to this hypothesis AIDS is not contagious, not immunogenic, not treatable by vaccines or antiviral drugs, and HIV is just a passenger virus. The hypothesis explains why AIDS epidemics strike non-randomly if caused by drugs and randomly if caused by malnutrition, why they manifest in drug- and malnutrition-specific diseases, and why they are not self-limiting via anti-viral immunity. The hypothesis predicts AIDS prevention by adequate nutrition and abstaining from drugs, and even cures by treating AIDS diseases with proven medications.

Molecular beacons as diagnostic tools: technology and applications

Molecular beacons are single-stranded, fluorophore-labeled nucleic acid probes that are capable of generating a fluorescent signal in the presence of target, but are dark in the absence of target. Molecular beacons allow multiplex detection of PCR products in real time in a homogeneous assay format. Real time detection is inherently quantitative and affords a greater dynamic range than end-point detection methods. Reactions in a homogeneous assay format are sealed before amplification takes place, providing improved contamination control. A single cycler/reader instrument, coupled with automated sample preparation, results in higher throughput and greater ease of use. A multiplex qualitative assay that detects Chlamydia trachomatis and Neisseria gonorrhoeae, along with an internal control, has been developed. High specificity is achieved through careful selection of primers, probes and assay conditions. Quantitative HIV, HCV, and HBV viral load assays, with sensitivities of 50 copies/ml, 20 IU/ml, and 50 copies/ml, respectively, are achievable. The viral load assays are designed to quantitate all subtype and genotype specimens equivalently. A molecular beacon assay has been designed to detect a single nucleotide polymorphism in the beta2 adrenergic receptor gene.

Inhibition of the early phase of HIV replication by an isothiazolone, PD 161374

A new class of substituted 2'-benzisothiazolone represented by PD 161374 was discovered with antiviral activity against retroviruses similar to previously described nucleocapsid inhibitor PD 159206 (DIBA-4). In T cell culture, the 50% inhibitory concentrations (EC(50)) of PD 161374 and PD 159206 were on average 2.5 microM (ranges of 1.2-13.5 microM) without any cytotoxic effect up to 100 microM. PD 161374 inhibited acute HIV infection and it was effective when added during the early phase of HIV infection. However, very modest effects were observed in chronically infected H9 cells and the HIV latency model line OM-10.1. Direct PCR analysis of infected cells demonstrated that PD 161374 delayed the appearance of completed HIV-cDNA products including 2LTR circles. Together all these results suggest that PD 161374 exerts its antiviral effect at pre-integration steps in the early phase of the virus life cycle. When combined with a protease inhibitor, PD 161374 did not show any antagonism and combination with a reverse transcriptase inhibitor (AZT) resulted in a synergistic effect.

Studies of macromolecular prodrugs of zidovudine

The current problems in controlling severe viral infections such as AIDS as well as the lack of effective and safe therapeutic measures for such diseases have caused interest in systems such as macromolecular prodrugs potentially able to solve heavier drawbacks of conventional antiviral therapy. This review focuses on various approaches proposed in the literature in this field. Neoglycoproteins and synthetic protein-like structure polymers have been mainly proposed. In the first group, the possibility of incorporating into the polymeric structures a determined amount of sugar molecules make them interesting candidates for targeting of infected blood cells. The conjugate of zidovudine (AZT) and an anti-transferrin receptor antibody OX-26 has been proposed for brain targeting. The conjugate of AZT with alpha,beta-poly(N-hydroxyethyl)-DL-aspartamide (PHEA) showed good release properties in a prolonged time.

Pregnancy, HLA allogeneic challenge, and implications for AIDS etiology

Because of the large HLA genetic polymorphism, a human fetus usually has several paternal HLA antigens allogeneic to its mother. The maternal gamma-immunoglobulin (IgG) antibody response to fetal HLA alloantigens is noncytotoxic and associated with local suppression of maternal cell-mediated immunity (CMI) at the maternal-fetal interface. When mother and fetus are syngeneic for most HLA antigens, an increased risk exists for a maternal anti-placental cytotoxic CMI responses, compromising fetal survival. Local suppression of maternal CMI by an anti-HLA IgG response may have evolved to protect the fetoplacental unit from a maternal CMI cytotoxic reaction against expressed developmental neoantigens. A negative aspect of this adaptive response is that infectious organisms bearing HLA-homologous alloantigens (e.g. human immunodeficiency virus type 1, HIV-1) may generate a systemic IgG response suppressing CMI. Findings are reviewed suggesting this is an etiologic factor in the acquired immune deficiency syndrome (AIDS).

Phenotypic and functional characterization of lymphocytes derived from normal and HIV-1-infected human lymph nodes

Lymph nodes are the major site of cell-to-cell transmission and replication of HIV-1. Trafficking of CD4+ T lymphocytes into lymph nodes provides a continual supply of susceptible target lymphocytes, and conversely, recruitment of CD8+ T lymphocytes may be critical for the host response that attempts to control HIV-1 replication. The present study was undertaken as no detailed assessment of lymphocyte subpopulations in HIV-1-infected lymph nodes has previously been reported. Peripheral blood and single-cell suspensions prepared from lymph nodes of patients with HIV-1 and control subjects were analysed using three-colour flow cytometry. Approximately 80% of the lymphocytes in control lymph nodes were CD3+ T lymphocytes, of which over 65% were CD4+. The majority of the CD4+ and CD8+ T lymphocytes obtained from both lymph nodes and blood of control subjects were immunologically naive (CD45RA+). By contrast, in HIV-1-infected patients there was a significant reduction in the proportion of CD4+ T lymphocytes and an expansion of the CD8+ T lymphocyte subset in both lymph nodes and peripheral blood. Furthermore, a high proportion of these T lymphocytes displayed a marker for immunological memory (CD45RO+). T lymphocytes derived from HIV-1-infected lymph nodes also showed altered expression of the adhesion molecules, L-selectin and very late antigen-4 (VLA-4), but not leucocyte function-associated antigen-1 (LFA-1). In an in vitro adhesion assay, lymphocytes from HIV-1-infected nodes were significantly more adhesive than control lymphocytes on fibronectin, as well as recombinant human intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) substrates. This combination of altered lymphocyte subpopulations in the HIV-1-infected lymph nodes, as well as enhanced adhesion phenotype and function, suggests that T lymphocyte traffic to lymph nodes in HIV disease may be an important determinant of pathogenesis.

Human immunodeficiency virus infection: a review of the mode of infection, pathogenesis, disease course, and the general and clinical manifestations

Acquired immunodeficiency syndrome (AIDS) was first recognized in 1981 and in 1983 the virus responsible for this syndrome, the human immunodeficiency virus, was first isolated. There has been an increasing understanding of the many aspects related to infection with this virus and this review discusses the historical as well as the more recent findings related to infection with this virus. In particular, the pathogenesis, mode and course of infection are discussed followed by an overview of the general and oral manifestations of infection with this virus.

Mitochondria alterations and dramatic tendency to undergo apoptosis in peripheral blood lymphocytes during acute HIV syndrome

OBJECTIVE

To study alterations of mitochondrial membrane potential (delta psi) and the propensity to undergo apoptosis in peripheral blood lymphocytes (PBL) from subjects with acute HIV syndrome; and to evaluate possible modulations of these phenomena by antioxidants that can be used in therapy, such as N-acetyl-cysteine (NAC), nicotinamide (NAM), or L-acetyl-carnitine (LAC).

METHODS

Mitochondrial function and the tendency of PBL to undergo spontaneous apoptosis were studied on freshly collected PBL from patients with symptomatic, acute HIV-1 primary infection, which were cultured for different durations in the presence of absence of NAC. NAM or LAC. By a cytofluorimetric method allowing analysis of delta psi in intact cells, we studied the function of these organelles under the different conditions. PBL apoptosis was evaluated by the classic cytofluorimetric method of propidium iodide staining, capable of revealing the typical DNA hypodiploid peak.

RESULTS

Significant delta psi alterations and tendency to undergo apoptosis were present in PBL from the subjects we studied. Indeed, when cultured even for a few hours in the absence of any stimulus, a consistent number of cells died. However, the presence of even different levels of NAC, NAM or LAC was able to rescue most of them from apoptosis. Both a fall in delta psi and apoptosis were evident in PBL collected in the earliest phases of the syndrome (before seroconversion), and changed significantly after a few days. A significant correlation was found between spontaneous apoptosis and tumour necrosis factor (TNF)-alpha or p24 plasma levels, as well as between apoptosis and the percentages of circulating CD4+ or CD8+ T cells.

CONCLUSIONS

PBL from patients with acute HIV syndrome are characterized by both significant mitochondrial alterations and a dramatic tendency to undergo apoptosis. The use of NAC, NAM or LAC seems to rescue cells through a protective effect on mitochondria, a well-known target for the action of TNF-alpha and for reactive oxygen species, the production of which is strongly induced by this cytokine. Thus, our data could provide the rationale for the use of such agents in addition to antiviral drugs in primary infection.

Chimpanzees in AIDS Research

Although the chimpanzee displays an immunological response to an HIV-1 challenge, it is a deficient animal model in AIDS research since it never develops the progressive symptoms of the disease. The continued use of the chimpanzee is also precluded because of its endangered status in the wild, the high cost per animal, and its failure to exhibit a CD4 decline (apoptosis) while infected. However, it is likely that the chimpanzee model will continue to be used in investigations relating to the epidemiology and mucosal transmission of the human AIDS virus.

Foreign-protein-mediated immunodeficiency in hemophiliacs with and without HIV

Hemophilia-AIDS has been interpreted in terms of two hypotheses: the foreign-protein-AIDS hypothesis and the Human Immunodeficiency Virus (HIV)-AIDS hypothesis. The foreign-protein-AIDS hypothesis holds that proteins contaminating commercial clotting factor VIII cause immunosuppression. The foreign-protein hypothesis, but not the HIV hypothesis, correctly predicts seven characteristics of hemophilia-AIDS: 1) The increased life span of American hemophiliacs in the two decades before 1987, although 75% became infected by HIV--because factor VIII treatment, begun in the 1960s, extended their lives and simultaneously disseminated harmless HIV. After 1987 the life span of hemophiliacs appears to have decreased again, probably because of widespread treatment with the cytotoxic anti-HIV drug AZT. 2) The distinctly low, 1.3-2%, annual AIDS risk of hemophiliacs, compared to the higher 5-6% annual risk of intravenous drug users and male homosexual aphrodisiac drug users--because transfusion of foreign proteins is less immunosuppressive than recreational drug use. 3) The age bias of hemophilia-AIDS, i.e. that the annual AIDS risk increased 2-fold for each 10-year increase in age--because immunosuppression is a function of the lifetime dose of foreign proteins received from transfusions. 4) The restriction of hemophilia-AIDS to immunodeficiency diseases--because foreign proteins cannot cause non-immunodeficiency AIDS diseases, like Kaposi's sarcoma. 5) The absence of AIDS diseases above their normal background in sexual partners of hemophiliacs--because transfusion-mediated immunotoxicity is not contagious. 6) The occurrence of immunodeficiency in HIV-free hemophiliacs--because foreign proteins, not HIV, suppress their immune system. 7) Stabilization, even regeneration, of immunity of HIV-positive hemophiliacs by long-term treatment with pure factor VIII. This shows that neither HIV nor factor VIII plus HIV are immunosuppressive by themselves. Therefore, AIDS cannot be prevented by elimination of HIV from the blood supply and cannot be rationally treated with genotoxic antiviral drugs, like AZT. Instead, hemophilia-AIDS can be prevented and has even been reverted by treatment with pure factor VIII.

B-cell continuous epitopes of the SIVmac-251 envelope protein in experimentally infected macaques

The humoral immune response of 34 macaques experimentally infected with SIVmac-251 was studied using a combination of an epitope library and synthetic peptides. The course of the immune response was checked for up to 9 months postinfection with a panel of clones expressing SIV fragments. A systematic study was performed with synthetic peptides covering the whole transmembrane (TM) and external (SU) envelope proteins. Seven major immunodominant epitopes were characterized. Four are localized in the SU protein: one in the V1 region (111-130), one in the Cys loop of the V3 region (311-330) and two in the C-terminal end (501-520 and 511-530). Three are localized in the TM protein: one in the extracellular domain (601-619), one in the anchor domain (731-750) and one in the intracytoplasmic domain (861-881). Among these epitopes, only one, 601-619, was found to be reactive with all sera and can be defined as the principal immunodominant epitope.

Scientific surveillance and the control of AIDS: a call for open debate

This paper reviews some of the history of AIDS in order to put into perspective the claim that AIDS is or will be the pandemic plague of the twentieth century. It is concluded that AIDS shows a relatively stable and predictable pattern in the developed world, and that open and unbiased debate about AIDS is long overdue.

Analysis in human immunodeficiency virus type 1 vectors of cis-acting sequences that affect gene transfer into human lymphocytes

Human immunodeficiency virus type 1 (HIV-1) can be used to generate recombinant viral vectors for delivery of heterologous genes to human CD4-positive lymphocytes. To define the cis-acting sequences required for efficient gene transfer, a number of HIV-1 vectors containing a previously identified packaging signal, long terminal repeats, and additional gag, pol, and env viral sequences were designed. By providing the viral proteins in trans, recombinant viruses were generated and analyzed for their abilities to transfer genes into human T lymphocytes. Inclusion of up to 653 nucleotides derived from the 5' end of the gag gene in the vector improved the efficiency of gene transfer, but inclusion of additional gag or pol sequences did not further improve this efficiency. The increased efficiency of gene transfer associated with the inclusion of 5' gag sequences in the vector arose, at least in part, from an increase in the packaging of vector RNA. The presence of the Rev-responsive element (RRE) increased the efficiency of transfer of vectors containing significant lengths of gag sequence, as expected from the Rev requirement for nucleus-to-cytoplasm transport of unspliced vector RNA containing intact packaging signals. However, the presence of a RRE did not affect the transfer efficiency of smaller vectors lacking significant lengths of gag sequences, arguing against a specific role for the RRE in packaging or vector transfer. These results contribute to an understanding of the minimal cis-acting sequences that operate in the context of HIV-1 vectors for delivering genes into human lymphocytes.

Simian immunodeficiency virus RNA is efficiently encapsidated by human immunodeficiency virus type 1 particles

Packaging of retroviral RNA is attained through the specific recognition of a cis-acting encapsidation site (located near the 5' end of the viral RNA) by components of the Gag precursor protein. Human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus (SIV) are two lentiviruses that lack apparent sequence similarity in their putative encapsidation regions. We used SIV vectors to determine whether HIV-1 particles can recognize the SIV encapsidation site and functionally propagate SIV nucleic acid. SIV nucleic acid was replicated by HIV-1 proteins. Thus, efficient lentivirus pseudotyping can take place at the RNA level. Direct examination of the RNA contents of virus particles indicated that encapsidation of this heterologous RNA is efficient. Characterization of deletion mutants in the untranslated leader region of SIV RNA indicates that only a very short region at the 5' end of the SIV RNA is needed for packaging. Comparison of this region with the corresponding region of HIV-1 reveals that both are marked by secondary structures that are likely to be similar. Thus, it is likely that a similar higher-order RNA structure is required for encapsidation.

Human immunodeficiency virus vectors for inducible expression of foreign genes

Tat-dependent expression of an endogenous lethal or deleterious foreign gene might be useful for abrogating the production of human immunodeficiency virus (HIV) from cells. This type of HIV-induced cellular killing, as well as other approaches to gene therapy for HIV infection, would be facilitated by simple HIV vectors that express introduced genes in a Tat-inducible manner. As part of studies to examine the feasibility of this concept, we constructed HIV-1 vectors that express the hygromycin B phosphotransferase gene (Hygr) in a Tat-dependent manner. Comparison of the efficiency of propagation of each vector indicates that sequences extending into the gag open reading frame are necessary in cis for efficient vector propagation. Southern blot analysis of genomic DNA isolated from vector-infected cells demonstrated that the vectors were capable of being propagated as expected without gross rearrangements or deletions. A fragment of the influenza A virus hemagglutinin (H5 HA) gene, capable of eliciting antibody and cytotoxic T-cell responses, was used as a marker for further characterization of the vector system. A Tat-dependent vector conferring the H5 HA+ phenotype was assayed by indirect immunofluorescence, and cells which contained but did not express the H5 HA gene were isolated. The activation of H5 HA expression following HIV infection of Tat- cells that stably contained but did not express the H5 HA construct was determined to be an efficient process.

Conserved cysteine residues in the human immunodeficiency virus type 1 transmembrane envelope protein are essential for precursor envelope cleavage

The transmembrane (TM) protein of human immunodeficiency virus type 1 has been demonstrated to be involved in viral infectivity and syncytium formation. Two highly conserved cysteine residues in the extracellular region of the TM protein are shown to be essential for processing the 160-kDa envelope precursor into the active 120- and 41-kDa mature forms.

The role of drugs in the origin of AIDS

It is proposed that the new American and European AIDS epidemics are caused by recreational and anti-HIV drugs rather than by human immunodeficiency virus (HIV). Chronologically, the AIDS epidemic in the 1980s followed a massive escalation in the consumption of recreational drugs that started in the 1960s and 70s. Epidemiologically, both epidemics derive about 80% of their victims from the same groups of 20-44 year-olds, of which 90% are males. In America 32% of these are intravenous drug users and their children, about 60% are male homosexuals who are long-term users of oral aphrodisiac drugs and an unknown percentage are prescribed the cytotoxic DNA chain terminator AZT, as inhibitor of HIV. Direct evidence indicates that these drugs are necessary for HIV-positives and sufficient for HIV-negatives to develop AIDS diseases. The drug-AIDS hypothesis predicts correctly that: (i) AIDS is new in the US, because the drug epidemic is new, while the HIV epidemic is old--fixed at a constant 1 million Americans since 1985; (ii) despite an increase in venereal diseases, AIDS remains restricted to long-term drug users and small groups with clinical deficiencies; (iii) over 72% of AIDS occurs in 20-44 year-old males, because they make up over 80% of hard psychoactive drug use; (iv) distinct AIDS diseases correlate with the use of distinct drugs, eg Kaposi's sarcoma with nitrite inhalants, tuberculosis with intravenous drugs, and leukopenia, anemia, and nausea with AZT; (v) AIDS diseases are only acquired after long-term drug consumption, rather than after single contacts as the virus-hypothesis predicts. The drug hypothesis can be tested epidemiologically and experimentally in animals. It predicts that most AIDS can be prevented by stopping the consumption of drugs, and provides a rational basis for therapy.

AIDS acquired by drug consumption and other noncontagious risk factors

The hypothesis that human immunodeficiency virus (HIV) is a new, sexually transmitted virus that causes AIDS has been entirely unproductive in terms of public health benefits. Moreover, it fails to predict the epidemiology of AIDS, the annual AIDS risk and the very heterogeneous AIDS diseases of infected persons. The correct hypothesis must explain why: (1) AIDS includes 25 previously known diseases and two clinically and epidemiologically very different epidemics, one in America and Europe, the other in Africa; (2) almost all American (90%) and European (86%) AIDS patients are males over the age of 20, while African AIDS affects both sexes equally; (3) the annual AIDS risks of infected babies, intravenous drug users, homosexuals who use aphrodisiacs, hemophiliacs and Africans vary over 100-fold; (4) many AIDS patients have diseases that do not depend on immunodeficiency, such as Kaposi's sarcoma, lymphoma, dementia and wasting; (5) the AIDS diseases of Americans (97%) and Europeans (87%) are predetermined by prior health risks, including long-term consumption of illicit recreational drugs, the antiviral drug AZT and congenital deficiencies like hemophilia, and those of Africans are Africa-specific. Both negative and positive evidence shows that AIDS is not infectious: (1) the virus hypothesis fails all conventional criteria of causation; (2) over 100-fold different AIDS risks in different risk groups show that HIV is not sufficient for AIDS; (3) AIDS is only 'acquired,' if at all, years after HIV is neutralized by antibodies; (4) AIDS is new but HIV is a long-established, perinatally transmitted retrovirus; (5) alternative explanations disprove all assumptions and anecdotal cases cited in support of the virus hypothesis; (6) all AIDS-defining diseases occur in matched risk groups, at the same rate, in the absence of HIV; (7) there is no common, active microbe in all AIDS patients; (8) AIDS manifests in unpredictable and unrelated diseases; and (9) it does not spread randomly between the sexes in America and Europe. Based on numerous data documenting that drugs are necessary for HIV-positives and sufficient for HIV-negatives to develop AIDS diseases, it is proposed that all American/European AIDS diseases, that exceed their normal background, result from recreational and anti-HIV drugs. African AIDS is proposed to result from protein malnutrition, poor sanitation and subsequent parasitic infections. This hypothesis resolves all paradoxes of the virus-AIDS hypothesis. It is epidemiologically and experimentally testable and provides a rational basis for AIDS control.

Demonstration of two distinct cytopathic effects with syncytium formation-defective human immunodeficiency virus type 1 mutants

The mechanism of human immunodeficiency virus type 1 (HIV-1) cytopathicity is poorly understood and might involve formation of multinucleated giant cells (syncytia), single-cell lysis, or both. In order to determine the contributions of the fusion domain to syncytium formation, single-cell lysis, and viral infectivity and to clarify the molecular details of these events, insertion mutations were made in the portion of env encoding this sequence in the functional HIV-1 proviral clone HXB2. Viruses produced from these mutant clones were found to have a partial (F3) or complete (F6) loss of syncytium-forming ability in acutely infected CEM, Sup T1, and MT4 T-cell lines. During the early stage of acute infection by F6 virus, there was a loss of the syncytial cytopathic effect, which resulted in increased cell viability, and a 1.9- to 2.6-fold increase in virus yield in the cell lines tested. In the late stage of acute infection, the single-cell cytopathic effect of F6 virus was similar to that of the parental HXB2 virus. The F3 and F6 viruses were also found to have a 1.7- to 43-fold reduction in infectivity compared with the HXB2 virus. The mutant F3 and F6 and parental HXB2 envelope proteins were expressed in vaccinia virus, and the mutant envelope proteins were observed to be defective in their ability to form syncytia. BSC-40 cells infected with vaccinia virus recombinants revealed no differences in kinetics of cleavage, cell surface expression, or CD4 binding capacity of the mutant and parental envelope proteins. These results demonstrate that a loss of syncytium formation results in an attenuation of infectivity and a loss of the syncytial cytopathic effect without a loss of single-cell lysis. These mutants may reflect in tissue culture the changes observed in the HIV isolates in vivo during disease progression, which exhibit marked differences in syncytium production.