36 research outputs found
Recombinant CXCR4/CCR5 hybrid receptors as tools for studies of HIV-1 receptor usage
No full textThe chemokine receptors CCR5 and CXCR4 are required, together with CD4, for the entry of HIV-1 into target cells. CCR5 using HIV-1 dominates during transmission and the asymptomatic phase of infection. During progression, virus phenotypes with the ability to use CXCR4 emerge in about 50% of infected individuals. Individuals continuously harbouring CCR5-restricted isolates still progress to AIDS. Differences among CCR5 using isolates, has been found and an evolution towards an altered mode of CCR5 coreceptor use and a reduced sensitivity to inhibition by natural CCR5 ligands has also been described. With the aim to study interactions of natural ligands and HIV-1 isolates with these chemokine receptors, a set of hybrid CXCR4/CCR5 receptors were constructed. Signalling response to their respective natural ligands, SDF-1 and RANTES were studied and prototypic R5 and X4 isolates (HIV-1BaL and HIV-1IIIB) were tested for their ability to use these chimeric receptors. The results showed that ligands and virus use different receptor epitopes which, in turn, vary between the two receptors. Further, the evolution of primary HIV-1 isolates was studied. A total of 246 sequential primary HIV-1 isolates were studied. Using our chimeric CXCR4/CCR5 receptors, we showed that R5 isolates from immunosuppressed individuals are distinct from those isolated from individuals with higher CD4+ T-cell counts, with regards to coreceptor usage. The analysis also showed that the ability to utilize chimeric receptors correlated inversely with the sensitivity to RANTES inhibition of infection. The R5 isolates used receptor chimeras to various degrees. Based on these results, the R5 viruses could be subdivided into two groups: the R5narrow phenotype and the R5broad phenotype. The R5narrow phenotype is defined as viruses that use wt CCR5 but no chimeric receptors, whereas viruses using at least one chimeric receptor in addition to CCR5, are designated R5broad viruses. The mode of coreceptor use by paired plasma and CSF isolates from HIV-1 infected individuals with varying degree of immunodeficiency and neuropathology were studied. The R5 viral phenotypes predominated both in plasma and in CSF. We were able to identify discordant plasma/CSF wt coreceptor use but also, varying R5 viral phenotypes in the paired isolates within individual patients. There were no characteristic patterns of receptor use that could distinguish CSF from plasma isolates. R5 virus use of chimera FC-2 correlated highly with immunosuppression. Efficient chimeric receptor use also correlated, with an increased resistance to inhibition by the CCR5 antagonist TAK-779. In conclusion, our findings propose that alterations in the mode of CCR5 use may be a key event in R5 virus pathogenesis. We believe that R5 virus ability to utilize these CXCR4/CCR5 chimeric receptors reflects a more flexible and more efficient CCR5 usage, which may include a reduced dependency upon interactions with the N-terminal of the receptor for infection. The findings are important, not only with regards to R5-virus pathogenesis and optimization of emerging treatment with CCR5 antagonists, but also for HIV-infection within the CNS
Recombinant CXCR4/CCR5 hybrid receptors as tools for studies of HIV-1 receptor usage [Elektronisk resurs]
No full textPopular Abstract in Swedish Människan är uppbyggd av ett stort antal celler. För att kroppens olika organ ska kunna samverka och för att kroppen ska kunna fungera som en helhet, måste de olika cellerna kommunicera med varandra. Cellernas kommunikationssystem är uppbyggt av mottagare, s.k. receptorer, på de olika cellernas yta och signaler som skickas runt mellan cellerna. Receptorerna och signalerna fungerar som nyckel och lås, d.v.s. när rätt signal når rätt receptor så får just den cellen information från andra celler och omgivningen. På det sättet når en viss information bara de celler som behöver just den upplysningen. Olika delar av kroppen dirigeras för att fungera på ett visst sätt, vid ett tillfälle. Signalerna kan exempelvis bestå av luktsignaler, hormoner, ljus som lyser in i ögat eller ämnen som påverkar kroppens immunsystem. De flesta receptorer tillhör en familj som heter GPCR. Man har uppskattat att det finns ungefär 800 olika GPCR-receptorer i vår kropp varav ungefär hälften bearbetar luktsignaler som kommer in via näsan. Ett flertal andra signaler och receptorer gör att vårt immunförsvar samarbetar. Immunförsvaret får signaler om främmande ämnen som kommit in i kroppen, eller från en skada som skett i något av kroppens organ. Med hjälp av olika signaler kan sedan immunsystemet agera för att ta bort ämnet eller för att reparera skadan i kroppen. År 1981 började man lägga märke till att ett flertal människor i världen drabbades av en ny okänd sjukdom som bröt ner immunförsvaret. Dessa tidigare friska människors immunsystem fungerade inte längre och de blev sjuka och dog av olika infektionssjukdomar och cancersjukdomar. År 1983 fann man att viruset HIV (Human immunodeficiency virus) orsakade denna nya sjukdom, AIDS (Acquired immunodeficiency syndrome). Sedan dess har många människor i världen blivit infekterade och avlidit i AIDS. Detta arbete handlar om två GPCR-receptorer, CCR5 och CXCR4, som normalt fungerar i kroppens immunförsvar. 1996 visade det sig att dessa två receptorer utnyttjas av HIV när det tar sig in och infekterar olika celler i kroppen. Utan dessa receptorer på cellytan kan cellerna inte infekteras. Denna nya kunskap ledde till att intresset för hur HIV använder sig av och kommer in i cellerna via dessa receptorer, blev mycket stort. När en person blir infekterad använder HIV nästan alltid den ena receptorn CCR5. Hos personer som är svårt sjuka i AIDS har man kunnat visa att de virus som de har i kroppen då, ofta använder den andra receptorn, CXCR4. Det verkar alltså som att HIV förändras under den tid det tar från att man smittats, tills man är svårt sjuk i AIDS, något som ofta tar många år. I det här arbetet har vi tagit reda på mer om hur det går till när HIV tar sig in i cellerna genom att använda dessa receptorer. För att kunna göra detta tillverkade jag blandreceptorer (hybrider), som består av delar från både CCR5 och den andra receptorn CXCR4. I ett första arbete visade vi att HIV använder receptorerna på andra sätt än immunförsvarets naturliga signalämnen. Resultatet visade att man kan utveckla HIV-läkemedel som blockerar användandet av dessa receptorer utan att störa de naturliga signalerna som överförs via receptorerna. Genom samarbeten med Lunds universitetssjukhus och Sahlgrenska universitets-sjukhuset i Göteborg har vi kunnat ta fram HIV från ett flertal patienter. HIV från smittade, fortfarande relativt friska personer, samt från patienter som är svårt sjuka i AIDS, har isolerats. Med hjälp av de konstgjorda hybridreceptorerna har vi sedan kunnat visa att dessa olika HIV-isolat använder receptorerna på olika sätt för att ta sig in i cellerna. Det sker alltså en utveckling av viruset under sjukdomsprocessen. Viruset förändrar sitt sätt att använda receptorn, CCR5, när personen blir sjukare och det blir också svårare att blockera infektionen med vissa typer av HIV-läkemedel. Vi har dessutom isolerat HIV från hjärnan för att jämföra med HIV som finns i kroppens blodbanor utanför hjärnan. Även här har vi kunnat se skillnader i hur viruset använder CCR5 och att viruset i hjärnan ibland skiljer sig från viruset i blodbanan, hos en och samma person. Detta ökar förståelsen för den speciella AIDS-demens som patienter kan drabbas av. Även i denna studie hittade vi virus med olika känslighet för blockering med läkemedel. Hybridreceptorerna som har använts i de tre studier som avhandlingen bygger på, har visat sig vara mycket bra verktyg för att förstå infektionen och sjukdomsprocessen. Genom att lära sig mer om hur HIV fungerar och tar sig in i den infekterade personens olika celler i kroppen, kan man öka kunskapen om sjukdomen, optimera behandlingen, samt lättare utveckla nya läkemedel mot HIV och sjukdomen AIDS.The chemokine receptors CCR5 and CXCR4 are required, together with CD4, for the entry of HIV-1 into target cells. CCR5 using HIV-1 dominates during transmission and the asymptomatic phase of infection. During progression, virus phenotypes with the ability to use CXCR4 emerge in about 50% of infected individuals. Individuals continuously harbouring CCR5-restricted isolates still progress to AIDS. Differences among CCR5 using isolates, has been found and an evolution towards an altered mode of CCR5 coreceptor use and a reduced sensitivity to inhibition by natural CCR5 ligands has also been described. With the aim to study interactions of natural ligands and HIV-1 isolates with these chemokine receptors, a set of hybrid CXCR4/CCR5 receptors were constructed. Signalling response to their respective natural ligands, SDF-1 and RANTES were studied and prototypic R5 and X4 isolates (HIV-1BaL and HIV-1IIIB) were tested for their ability to use these chimeric receptors. The results showed that ligands and virus use different receptor epitopes which, in turn, vary between the two receptors. Further, the evolution of primary HIV-1 isolates was studied. A total of 246 sequential primary HIV-1 isolates were studied. Using our chimeric CXCR4/CCR5 receptors, we showed that R5 isolates from immunosuppressed individuals are distinct from those isolated from individuals with higher CD4+ T-cell counts, with regards to coreceptor usage. The analysis also showed that the ability to utilize chimeric receptors correlated inversely with the sensitivity to RANTES inhibition of infection. The R5 isolates used receptor chimeras to various degrees. Based on these results, the R5 viruses could be subdivided into two groups: the R5narrow phenotype and the R5broad phenotype. The R5narrow phenotype is defined as viruses that use wt CCR5 but no chimeric receptors, whereas viruses using at least one chimeric receptor in addition to CCR5, are designated R5broad viruses. The mode of coreceptor use by paired plasma and CSF isolates from HIV-1 infected individuals with varying degree of immunodeficiency and neuropathology were studied. The R5 viral phenotypes predominated both in plasma and in CSF. We were able to identify discordant plasma/CSF wt coreceptor use but also, varying R5 viral phenotypes in the paired isolates within individual patients. There were no characteristic patterns of receptor use that could distinguish CSF from plasma isolates. R5 virus use of chimera FC-2 correlated highly with immunosuppression. Efficient chimeric receptor use also correlated, with an increased resistance to inhibition by the CCR5 antagonist TAK-779. In conclusion, our findings propose that alterations in the mode of CCR5 use may be a key event in R5 virus pathogenesis. We believe that R5 virus ability to utilize these CXCR4/CCR5 chimeric receptors reflects a more flexible and more efficient CCR5 usage, which may include a reduced dependency upon interactions with the N-terminal of the receptor for infection. The findings are important, not only with regards to R5-virus pathogenesis and optimization of emerging treatment with CCR5 antagonists, but also for HIV-infection within the CNS
HIV-1 with Multiple CCR5/CXCR4 Chimeric Receptor Use Is Predictive of Immunological Failure in Infected Children
No full textBACKGROUND: HIV-1 R5 viruses are characterized by a large phenotypic variation, that is reflected by the mode of coreceptor use. The ability of R5 HIV-1 to infect target cells expressing chimeric receptors between CCR5 and CXCR4 (R5(broad) viruses), was shown to correlate with disease stage in HIV-1 infected adults. Here, we ask the question whether phenotypic variation of R5 viruses could play a role also in mother-to-child transmission (MTCT) of HIV-1 and pediatric disease progression.
METHODOLOGY/PRINCIPAL FINDINGS: Viral isolates obtained from a total of 59 HIV-1 seropositive women (24 transmitting and 35 non transmitting) and 28 infected newborn children, were used to infect U87.CD4 cells expressing wild type or six different CCR5/CXCR4 chimeric receptors. HIV-1 isolates obtained from newborn infants had predominantly R5(narrow) phenotype (n = 20), but R5(broad) and R5X4 viruses were also found in seven and one case, respectively. The presence of R5(broad) and R5X4 phenotypes correlated significantly with a severe decline of the CD4+ T cells (CDC stage 3) or death within 2 years of age. Forty-three percent of the maternal R5 isolates displayed an R5(broad) phenotype, however, the presence of the R5(broad) virus was not predictive for MTCT of HIV-1. Of interest, while only 1 of 5 mothers with an R5X4 virus transmitted the dualtropic virus, 5 of 6 mothers carrying R5(broad) viruses transmitted viruses with a similar broad chimeric coreceptor usage. Thus, the maternal R5(broad) phenotype was largely preserved during transmission and could be predictive of the phenotype of the newborn's viral variant.
CONCLUSIONS/SIGNIFICANCE: Our results show that R5(broad) viruses are not hampered in transmission. When transmitted, immunological failure occurs earlier than in children infected with HIV-1 of R5(narrow) phenotype. We believe that this finding is of utmost relevance for therapeutic interventions in pediatric HIV-1 infectio
Virus phenotype variability during disease progression of HIV-1 infected children
No full textBackground
HIV-1 infected children display different clinical evolution,
i.e., “fast progression” (FP), “slow progression” (SP)
and “long term non progression” (LTNP). One important
phenotypic trait linked to disease progression is the evolution
of the viral co-receptor use [1], involving a change
from CCR5 to CXCR4 use [2]. However, AIDS symptoms
can appear in absence of X4 viruses. Recently chimeric
receptors between CCR5 and CXCR4 were developed, in
which subsequent parts of CCR5 were replaced with corresponding
parts of CXCR4 [3]. Their use allowed to document
the biological variability of R5 isolates during the
pathogenic process in adults [4].
Aim
To examine the HIV biological variability in children with
different modes of disease progression.
Materials and methods
119 isolates from19 HIV-1 positive children were tested
for their ability to infect U87.CD4+ cells expressing the
wild type receptor CCR5, CXCR4, or one of the 6 chimeric
CCR5/CXCR4 receptors.
Results
Early during infection, all the viruses isolated from 8 SP
children used only wild type CCR5 (called R5narrow). In
one case, this phenotype persisted during disease progression,
whereas in 2 children the virus evolved and was able
to use multiple chimeric receptors (called R5broad), and in
additional 5 children the virus evolved to CXCR4 usage.
Interestengly the FP children, carried close to birth in 2
cases R5narrow virus, in 2 cases R5broad and in one case a
dualtropic R5X4 virus. Virus with R5narrow evolved to
R5broad in one of the 2 children carrying such phenotype.
Both children with R5broad phenotype developed CXCR4
variants during the follow-up.
Evolution was observed also in the LTNP, although followed
from later on in life (>8 years of age): all tested isolates
from 2/6 LTNP remained R5narrow during disease
progression; in one child an evolution from R5narrow to
R5broad was observed whereas in another child the virus
evolved from R5narrow to R5X4. The remaining two children
showed R5broad phenotype during the whole followup.
Conclusions
Our results show that HIV-1 with broad chimeric receptor
use is not hampered in transmission, and is more frequent
close to birth in FP than in SP children. Viruses from LTNP
show a similar phenotypic evolution though at later age
Optimized reporter gene assays based on a synthetic multifunctional promoter and a secreted luciferase.
No full textEfficient screening for ligands of seven-transmembrane, G-protein-coupled receptors, whether transfected or endogenously expressed, often involves cell-based reporter assays. Here we describe the development of reporter gene assays in HeLa cells. The reporter construct includes a synthetic multifunctional promoter with several different response motifs (NF-kappaB, STAT, and AP-1) and hence efficiently funnels several signaling pathways. The assay, performed with the resulting reporter cell line HFF11, has an exceptional high Z-factor and a large signal-to-background ratio. To facilitate cell handling during screening, we introduced a secreted Renilla luciferase as a reporter enzyme. HR36 reporter cells, equipped with the construct, were added to ligands present in a multiwell plate and after addition of coelenterazine they produced a luminescence readout. This procedure economizes cell handling and at the same time increases assay quality and sensitivit
Monolayer culturing and cloning of human pluripotent stem cells on laminin-521–based matrices under xeno-free and chemically defined conditions
No full textMolecular mapping of epitopes for interaction of HIV-1 as well as natural ligands with the chemokine receptors, CCR5 and CXCR4.
No full textOBJECTIVE: Mapping coreceptor epitopes used by the prototypic R5 and X4 strains, HIV-1BaL and HIV-1IIIB, in comparison with epitopes involved in the activation and signaling induced by the natural ligands, RANTES and SDF-1beta. DESIGN: Receptor hybrids between CCR5 and CXCR4 were constructed. METHODS: Using single-overlap and extension PCR, increasing portions of CCR5 were replaced with corresponding parts of CXCR4. Viral interaction with these constructs was monitored in infection experiments using stably transfected cell lines, and ligand-induced activation of cells transiently expressing the constructs was measured in terms of calcium fluxes. RESULTS: SDF-1beta required an essentially complete CXCR4, whereas RANTES demanded both the N terminus and the first two extracellular loops of CCR5. HIV-1 infection experiments emphasized the importance of the CCR5 N terminus for infection with HIV-1BaL, whereas HIV-1IIIB was less demanding in its use of CXCR4. CONCLUSION: This study, for the first time monitoring CCR5 and CXCR4 ligand activation and HIV-1 interaction concomitantly, indicates that ligands and virus use different receptor epitopes which, in turn, vary between the two receptors. One particular chimera (FC-4b), having its junctional region close to the conserved cysteine in ECL2, functioned as coreceptor for both HIV-1BaL and HIV-1IIIB, but was not activated with RANTES or SDF-1beta. The results provide a basis for tailoring drugs that block viral entry through the two major coreceptors without interfering with their physiological function
Developmental insights and biomedical potential of human embryonic stem cells : modelling trophoblast differentiation and establishing novel cell therapies for age-related macular degeneration
No full textUnderstanding the molecular pathways responsible for lineage segregation in the preimplantation human embryo is critical in order to fully elucidate the mechanisms involved in pluripotency and differentiation of embryonic stem cells. A significant increase in our comprehension of such processes will lead to an improvement in the quality and efficiency of these cells for applications requiring stem cell maintenance and differentiation, such as regenerative medicine. Through responsible and ethical research, such new knowledge can then be translated effectively and efficiently into future advancements in health and medical practices. This thesis focuses on two different applications of human embryonic stem cells (hESC): first, as an in-vitro model to investigate the genetic requirements for human trophoblast formation and second, as a cell replacement therapy for age-related macular degeneration (AMD) through the establishment of efficient, scalable, and clinically compliant protocols for their differentiation into retinal pigment epithelium cells (RPE).In paper I, we used human embryonic stem cells to model trophoblast establishment and differentiation in order to better understand the mechanisms governing trophectoderm segregation in the embryo. Combining this in-vitro model with the use of pharmacological inhibitors and CRISPR/Cas9 genome editing, we demonstrated that blockade of the YAP1/WWTR1-TEAD complex impairs not only trophoblast differentiation, but also survival of undifferentiated stem cells. Furthermore, through systematic targeting of the different components of the complex, we described a dominant role for YAP1 in these processes and a striking genetic and functional redundancy of the function of TEAD proteins. Altogether, the findings indicate a role for the Hippo signaling pathway, both in human trophectoderm segregation and in maintaining human pluripotency.In papers II and III, we developed xeno-free and defined methodologies for the differentiation of human embryonic stem cells into RPE with the potential for use in replacement therapies for common retinal degenerative diseases, such as age-related macular degeneration. These invitro derived cells exhibited specific morphological and molecular features and functional properties that are typical of native RPE. In addition, upon subretinal transplantation into a large-eyed animal model, hESC-derived RPE cells were able to integrate and survive for extensive periods of time and rescued the neuroretina from the damage induced at the moment of injection. Finally, we identified a set of unique cell surface markers that were able to distinguish the RPE from other potential contaminating cell types or undifferentiated remnants and demonstrated their utility in monitoring differentiation efficiency and in increasing the purity and homogeneity of the final cell product. Through this work, we demonstrate that human embryonic stem cells hold enormous potential for modeling specific aspects of human development, which can help to elucidate the complex mechanisms governing lineage segregation and support the production of bona fide differentiated cell types to serve in future replacement therapies.List of scientific papersI. Alvaro Plaza Reyes, Nicolas Ortega, Theresa M. Sommer, Philipp Schenk, Ainhoa Larreategui, Fredrik Lanner‡. Role of Hippo Signaling Pathway in Human Trophoblast Differentiation. ‡Corresponding author. [Manuscript]II. Alvaro Plaza Reyes*, Sandra Petrus-Reurer*, Liselotte Antonsson, Sonya Stenfelt, Hammurabi Bartuma, Sarita Panula, Theresa Mader, Iyadh Douagi, Helder André, Outi Hovatta†, Fredrik Lanner†‡ and Anders Kvanta†. Xeno-free and defined human embryonic stem cell-derived retinal pigment epithelial cells functionally integrate in a large-eyed preclinical model. Stem Cell Reports. 2016;6:9-17. *Co-first author, †Co-senior author, ‡Corresponding author. https://doi.org/10.1016/j.stemcr.2015.11.008 III. Alvaro Plaza Reyes*, Sandra Petrus-Reurer*, Sara Padrell Sánchez, Pankaj Kumar, Iyadh Douagi, Hammurabi Bartuma, Monica Aronsson, Sofie Westman, Emma Lardner, Helder André, Anna Falk, Emeline F. Nandrot, Anders Kvanta, Fredrik Lanner‡. Identification of cell surface markers and establishment of monolayer differentiation to retinal pigment epithelial cells. Nature Communications. 2020;11:1609. *Co-first author, ‡Corresponding author. https://doi.org/10.1038/s41467-020-15326-5 </p
The relationship of technology and financial inclusion in three Southeast Asian markets
No full textIn this dissertation, the author analyses the relationship between technology and financial inclusion within three nascent markets in ASEAN. The markets studied were Cambodia, Laos, and Vietnam. These markets were chosen as they are lagging the other ASEAN countries in the development of FinTech and adaption to formal banking. These three markets generally have smaller populations, and a majority of them live in rural areas, which may have an impact on the adoption of new technology and services. The ratio of rural population was therefore represented in the sample taken. The data was collected using a quantitative in-person survey asking a sample of individuals from the relevant markets about their access and habits regarding technology, banking, and handling of money. 147 individuals took part in the survey and a logistics model was used to analyse the data collected through convenience sampling. The data collected revealed that most individuals have regular access to modern technologies like smartphones and the internet and that, self-reportedly, these technologies are used daily to perform bank services like payments and peer-to-peer money transfers. The survey mainly delivered binary data. The findings are relevant as they show the market maturity and usage of services provided by the FinTech-sector. Previously, most data collected regarding markets analyses the supply-side, and data collected from the demand-side are for economic policy rather than market analysis. Future research could be collecting the data over time to see the trends and impact.Na nesta dissertação a autora analisa a relação entre tecnologia e inclusão financeira no Camboja, Laos e Vietnã. Esses países foram escolhidos por estarem atrasados na adoção de tecnologia financeira (FinTech) e no uso do sistema bancário formal. Como grande parte da população vive em áreas rurais, a amostra considerou essa proporção para avaliar o impacto na adoção de novas tecnologias. Os dados foram coletados por meio de uma pesquisa quantitativa presencial com 147 indivíduos, abordando acesso e hábitos relacionados à tecnologia e serviços bancários. A análise foi feita com um modelo logístico, utilizando amostragem por conveniência. Os resultados mostram que a maioria tem acesso regular a smartphones e internet e usa essas tecnologias diariamente para serviços bancários, como pagamentos e transferências. A pesquisa gerou, principalmente, dados binários.Esses achados são relevantes, pois indicam a maturidade do mercado e o uso de serviços FinTech. Tradicionalmente, os dados coletados sobre esses mercados focam no lado da oferta, enquanto informações sobre a demanda são voltadas para políticas econômicas e não para análise de mercado. Pesquisas futuras podem acompanhar a evolução desses fatores ao longo do tempo
Dual R3R5 tropism characterizes cerebrospinal fluid HIV-1 isolates from individuals with high cerebrospinal fluid viral load
No full textObjective: To study the use of major and alternative coreceptors by HIV-1 isolates obtained from paired plasma and cerebrospinal fluid (CSF) samples. Design: Paired plasma and CSF isolates from HIV-1-infected individuals with varying clinical, virologic, and immunologic parameters were assessed for the ability to infect indicator cells expressing a panel of coreceptors with documented expression in the central nervous system (CNS). Methods: HIV-1 isolates obtained from plasma and CSF in 28 individuals with varying viral load, CD4(+) T-cell counts, and with or without AIDS-defining disease were analyzed for the ability to infect NP2.CD4 cells stably expressing a panel of HIV coreceptors (CCR5, CXCR4, CCR3, CXCR6, GPR1, APJ, ChemR23, RDC-1 or BLT1). Results: All isolates from both plasma and CSF utilized CCR5 and/or CXCR4. However, the ability to use both CCR3 and CCR5 (R3R5) was more pronounced in CSF isolates and correlated with high CSF viral load and low CD4(+) T-cell count. Notably, four out of five CSF isolates of subtype C origin exhibited CXCR6 use, which coincided with high CSF viral load despite preserved CD4(+) T-cell counts. The use of other alternative coreceptors was less pronounced. Conclusion: Dual-tropic R3R5 HIV-1 isolates in CSF coincide with high CSF viral load and low CD4(+) T-cell counts. Frequent CXCR6 use by CSF-derived subtype C isolates indicates that subtype-specific differences in coreceptor use may exist that will not be acknowledged when assessing plasma virus isolates. The findings may also bare relevance for HIV-1 replication within the CNS, and consequently, for the neuropathogenesis of AIDS. (C) 2012 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkin
