Glycan deletions in the HIV-1 gp120 V1/V2 domain compromise viral infectivity, sensitize the mutant virus strains to carbohydrate-binding agents and represent a specific target for therapeutic intervention

AbstractCarbohydrate-binding agents (CBAs), such as the mannose-specific Hippeastrum hybrid agglutinin (HHA) and the GlcNAc-specific Urtica dioica agglutinin (UDA), frequently select for glycan deletions in all different domains of HIV-1 gp120, except in the V1/V2 domain. To reveal the underlying mechanisms, a broad variety of 31 different virus strains containing one or several N-glycan deletions in V1/V2 of the gp120 of the X4-tropic HIV-1NL4.3 were constructed by chimeric virus technology. No co-receptor switch to CCR5 was observed for any of the replication-competent mutant virus strains. With a few exceptions, the more glycans were deleted in the gp120 V1/V2 domain, the more the replication capacity of the mutant viruses became compromised. None of the mutant virus strains showed a markedly decreased sensitivity to the inhibitory activity of HHA and UDA. Instead, an up to 2- to 10-fold higher sensitivity to the inhibitory activity of these CBAs was observed. Our data may provide an explanation why glycan deletions in the gp120 V1/V2 domain rarely occur under CBA pressure and confirm the important functional role of the glycans in the HIV-1 gp120 V1/V2 domain. The gp120 V1/V2 loop glycans of HIV-1 should therefore be considered as a hot spot and novel target for specific therapeutic drug intervention

HIV-1 protease mutation 82M contributes to phenotypic resistance to protease inhibitors in subtype G

Objectives The purpose of this study was the qualitative and quantitative assessment of the in vitro effect of HIV-1 protease (PR) mutation 82M on replication capacity and susceptibility to the eight clinically available PR inhibitors (PIs). Methods The 82M substitution was introduced by site-directed mutagenesis in wild-type subtype B and G strains, as well as reverted back to wild-type in a therapy-failing strain. The recombinant viruses were evaluated for their replication capacity and susceptibility to PIs. Results The single 82M mutation within a wild-type subtype B or G background did not result in drug resistance. However, the in vitro effect of single PR mutations on PI susceptibility is not always distinguishable from wild-type virus, and particular background mutations and polymorphisms are required to detect significant differences in the drug susceptibility profile. Consequently, reverting the 82M mutation back to wild-type (82I) in a subtype G isolate from a patient that failed therapy with multiple other PR mutations did result in significant increases in susceptibility towards indinavir and lopinavir and minor increases in susceptibility towards amprenavir and atazanavir. The presence of the 82M mutation also slightly decreased viral replication, whether it was in the genetic background of subtype B or subtype G. Conclusions Our results suggest that 82M has an impact on PI susceptibility and that this effect is not due to a compensatory effect on the replication capacity. Because 82M is not observed as a polymorphism in any subtype, these observations support the inclusion of 82M in drug resistance interpretation systems and PI mutation list

Plasma cells are not restricted to the CD27+ phenotype:characterization of CD27-CD43+ antibody-secreting cells

Circulating antibody-secreting cells are present in the peripheral blood of healthy individuals reflecting the continued activity of the humoral immune system. Antibody-secreting cells typically express CD27. Here we describe and characterize a small population of antibody-secreting class switched CD19+CD43+ B cells that lack expression of CD27 in the peripheral blood of healthy subjects. In this study, we characterized CD27-CD43+ cells. We demonstrate that class-switched CD27-CD43+ B cells possess characteristics of conventional plasmablasts as they spontaneously secrete antibodies, are morphologically similar to antibody-secreting cells, show downregulation of B cell differentiation markers, and have a gene expression profile related to conventional plasmablasts. Despite these similarities, we observed differences in IgA and IgG subclass distribution, expression of homing markers, replication history, frequency of somatic hypermutation, immunoglobulin repertoire, gene expression related to Toll-like receptors, cytokines, and cytokine receptors, and antibody response to vaccination. Their frequency is altered in immune-mediated disorders. Conclusion: we characterized CD27-CD43+ cells as antibody-secreting cells with differences in function and homing potential as compared to conventional CD27+ antibody-secreting cells.</p

HIV-1 drug resistance pathways: new methodologies and application to fusion inhibitors

Tijdens de behandeling van HIV-1 geïnfecteerde patiënten mag de virale r eplicatie niet waarneembaar zijn. De virale lading dient dus frequent na gegaan te worden om, indien nodig, tijdig de therapie te kunnen aanpasse n. Een arts dient dan te weten door welke antivirale middelen het virus nog onderdrukt kan worden. Genotypisch testen voor resistentie is de sne lste manier om deze kennis te vergaren. De interpretatie van de resultat en bekomen met zulke testen is echter complex en daarom wordt er gebruik gemaakt van resistentie interpretatie algoritmen. Deze zijn echter niet steeds betrouwbaar voor non-B subtype virussen. Antivirale middelen wor den meer en meer beschikbaar in regio s waar hoofdzakelijk non-B virusse n voorkomen. Door toegenomen migratie komen deze virussen meer voor in B elgië en Europa. Deze beide factoren maken dat er nood is aan het beter begrijpen van de invloed van de genetische diversiteit op de ontwikkelin g van resistentie aan antivirale middelen. Verder werken enkele van de onlangs goedgekeurde antiretrovirale middele n (ENF, MVC en RAL) in op andere processen dan deze uitgevoerd door de v irale Protease of Reverse transcriptase enzymen. Bijgevolg is de ontwikk eling van resistentie tegen deze nieuwe geneesmiddelen is niet te wijten aan mutaties in RT of PR en haar substraat gag, maar in de virale envel ope of integrase. Gezien het gebrek aan commercieel beschikbare genotypi sche resistentie testen die informatie geven omtrent deze doelwitgenen w as er een noodzaak tot het ontwikkelen en valideren van home-brew genoty pische resistentie testen. Voorafgaand aan de opneming van mutaties in resistentie interpretatie sy stemen moeten hun kwalitatieve en kwantitatieve fenotypische effecten mo eten worden gekarakteriseerd. Daarom ontwikkelden we een reproduceerbare en nauwkeurige fenotypische HIV-1 resistentie-test. Zowel voor genotypische en fenotypische testen werd rekening gehouden me t de internationale richtlijnen van de gevoeligheid en onze lokale klini sche situatie die wordt gekenmerkt door een grote virale diversiteit. Uit onderzoek naar ontwikkeling van resistentie tegen protease en revers e transcriptase inhibitoren blijkt reeds dat er subtype-specifieke resis tentie mutaties bestaan. Aangezien de virale envelop regio is nog gevari eerder dan de Pol regio, wilden we de ontwikkeling van resistentie tegen fusieremmer enfuvirtide onderzoeken in genetisch diverse varianten omda t eerder onderzoek was meestal beperkt tot virussen behorende tot subtyp e B. We vonden op heden niet beschreven mutaties in gp41 terug. Het effect va n deze mutaties op de gevoeligheid aan enfuvirtide en op de virale repli catie capaciteit werd onderzocht evenals de invloed van deze mutaties op de nieuwe fusieremmer sifuvirtide.status: publishe

Comment on "Pneumococcal polysaccharide vaccination induces polysaccharide-specific B cells in adult peripheral blood expressing CD19(+)CD20(+)CD3(-)CD70(-)CD27(+)IgM(+)CD43(+)CD5(+/-)"

publisher: Elsevier articletitle: Comment on “Pneumococcal polysaccharide vaccination induces polysaccharide-specific B cells in adult peripheral blood expressing CD19+CD20+CD3−CD70−CD27+IgM+CD43+CD5+/−” journaltitle: Vaccine articlelink: http://dx.doi.org/10.1016/j.vaccine.2013.10.058 content_type: simple-article copyright: Copyright © 2013 Elsevier Ltd. All rights reserved.status: publishe

Response: Extended analysis of microarray data does not contradict preplasmablast phenotype of human CD20+CD27+CD43+ cells

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Human CD20+CD43+CD27+CD5- B cells generate antibodies to capsular polysaccharides of Streptococcus pneumoniae

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Characterization of in vivo mutational patterns within HIV-1 group M viruses developed during long-term enfuvirtide therapy and after discontinuation on enfuvirtide

info:eu-repo/semantics/nonPublishe