Caractéristiques cliniques de la dégénérescence maculaire chez les personnes vivant avec le VIH / Clinical characteristics of macular degeneration in people living with HIV

Objectif : Décrire les caractéristiques cliniques de la dégénérescence maculaire (DM) chez les personnes vivant avec le VIH (PVVIH).Patients et méthodes : Il s'agissait d'une étude observationnelle menée dans le service d'infectiologie du CHU de Libreville. Il était inclus les adultes âgés de plus de 17 ans, vivant avec le VIH (PVVIH) type 1 et ayant le même protocole thérapeutique antirétroviral. Les paramètres recueillis étaient l'âge, le sexe, le taux de CD4, l'ancienneté de l'infection au VIH, le délai de mise sous traitement antirétroviral et les lésions rétiniennes en rapport avec la DM. Les paramètres des PVVIH sans DM (DM-) étaient comparés à ceux avec DM (DM+) (p < 0,05). Résultats : L'enquête avait concerné 772 personnes vivant avec le VIH (PVVIH) dont 30 avaient présenté une DM+, soit une fréquence de 4%. La moyenne d'âge des DM+ était de 50,3 ± 12,8 ans et celle des DM- de 44,9 ± 10,8 ans (0,0083).Le sex-ratio était de 0,3 chez les DM+ et de 0,24 chez les DM- (p = 0,5950). Parmi les DM+, 28 avaient une forme intermédiaire et 2 une forme tardive. Il n'existait pas de différence significative entre l'ancienneté de l'infection à VIH (p = 0,1599), le taux de CD4 (p = 0,8666) et le délai de mise sous traitement antirétroviral (p = 0,9040) entre les deux groupes (DM+, DM- ).Conclusion : Ce travail permet de constater que la dégénérescence maculaire chez les PVVIH est fréquente et précoce,avec une prédominance de la forme intermédiaire

Objective: To describe the clinicals characteristics of macular degeneration (MD) in people living with HIV.Patients and methods: This was an observational study carried out in the infectious disease department of the University Hospital of Libreville. It was included adults over the age of 17, living with type 1 HIV (PLHIV) and having the same antiretroviral therapy protocol. The parameters collected were age, gender, CD4 count, age of HIV infection, time to antiretroviral treatment, and retinal lesions related to MD. The PLHIV were divided into two groups, those without MD (MD-) and those with MD (MD+ ) (p <0.05).Results: The survey concerned 772 people living with HIV (PLHIV), of whom 30 presented with MD+, either a frequency of 4%. The mean age of DM+ was 50.3 ± 12.8 years and that of MD- 44.9 ± 10.8 years (0.0083). The sex ratio was 0.3 in DM+ and 0.24 in DM- (p = 0.5950). Of the MD+, 28 had an intermediate form and 2 had a late form. There was no significant difference between the age of HIV infection (p = 0.1599), CD4 count (p = 0.8666) and time to antiretroviral treatment (p = 0.9040) between the two groups (MD+, MD-).Conclusion: This work has shown that macular degeneration in PLHIV is frequent and early, with a predominance of theintermediate form

Synthetic DNA delivery by electroporation promotes robust in vivo sulfation of broadly neutralizing anti-HIV immunoadhesin eCD4-Ig.

BACKGROUND: Despite vigorous and ongoing efforts, active immunizations have yet to induce broadly neutralizing antibodies (bNAbs) against HIV-1. An alternative approach is to achieve prophylaxis with long-term expression of potent biologic HIV-1 inhibitors with Adeno-associated Virus (AAV), which could however be limited by hosts' humoral and cellular responses. An approach that facilitates in vivo production of these complex molecules independent of viral-vectored delivery will be a major advantage. METHODS: We used synthetic DNA and electroporation (DNA/EP) to deliver an anti-HIV-1 immunoadhesin eCD4-Ig in vivo. In addition, we engineered a TPST2 enzyme variant (IgE-TPST2), characterized its intracellular trafficking patterns and determined its ability to post-translationally sulfate eCD4-Ig in vivo. FINDINGS: With a single round of DNA injection, a peak expression level of 80-100µg/mL was observed in mice 14 days post injection (d.p.i). The engineered IgE-TPST2 enzyme trafficked efficiently to the Trans-Golgi Network (TGN). Co-administrating low dose of plasmid IgE-TPST2 with plasmid eCD4-Ig enhanced the potency of eCD4-Ig by three-fold in the ex vivo neutralization assay against the global panel of HIV-1 pseudoviruses. INTERPRETATION: This work provides a proof-of-concept for delivering anti-HIV-1 immunoadhesins by advanced nucleic acid technology and modulating protein functions in vivo with targeted enzyme-mediated post-translational modifications. FUNDING: This work is supported by NIH IPCAVD Grant U19 Al109646-04, Martin Delaney Collaboration for HIV Cure Research and W.W. Smith Charitable Trust.

eCD4-Ig Variants That More Potently Neutralize HIV-1.

The human immunodeficiency virus type 1 (HIV-1) entry inhibitor eCD4-Ig is a fusion of CD4-Ig and a coreceptor-mimetic peptide. eCD4-Ig is markedly more potent than CD4-Ig, with neutralization efficiencies approaching those of HIV-1 broadly neutralizing antibodies (bNAbs). However, unlike bNAbs, eCD4-Ig neutralized all HIV-1, HIV-2, and simian immunodeficiency virus (SIV) isolates that it has been tested against, suggesting that it may be useful in clinical settings, where antibody escape is a concern. Here, we characterize three new eCD4-Ig variants, each with a different architecture and each utilizing D1.22, a stabilized form of CD4 domain 1. These variants were 10- to 20-fold more potent than our original eCD4-Ig variant, with a construct bearing four D1.22 domains (eD1.22-HL-Ig) exhibiting the greatest potency. However, this variant mediated less efficient antibody-dependent cell-mediated cytotoxicity (ADCC) activity than eCD4-Ig itself or several other eCD4-Ig variants, including the smallest variant (eD1.22-Ig). A variant with the same architecture as the original eCD4-Ig (eD1.22-D2-Ig) showed modestly higher thermal stability and best prevented the promotion of infection of CCR5-positive, CD4-negative cells. All three variants, and eCD4-Ig itself, mediated more efficient shedding of the HIV-1 envelope glycoprotein gp120 than did CD4-Ig. Finally, we show that only three D1.22 mutations contributed to the potency of eD1.22-D2-Ig and that introduction of these changes into eCD4-Ig resulted in a variant 9-fold more potent than eCD4-Ig and 2-fold more potent than eD1.22-D2-Ig. These studies will assist in developing eCD4-Ig variants with properties optimized for prophylaxis, therapy, and cure applications.IMPORTANCE HIV-1 bNAbs have properties different from those of antiretroviral compounds. Specifically, antibodies can enlist immune effector cells to eliminate infected cells, whereas antiretroviral compounds simply interfere with various steps in the viral life cycle. Unfortunately, HIV-1 is adept at evading antibody recognition, limiting the utility of antibodies as a treatment for HIV-1 infection or as part of an effort to eradicate latently infected cells. eCD4-Ig is an antibody-like entry inhibitor that closely mimics HIV-1's obligate receptors. eCD4-Ig appears to be qualitatively different from antibodies, since it neutralizes all HIV-1, HIV-2, and SIV isolates. Here, we characterize three new structurally distinct eCD4-Ig variants and show that each excels in a key property useful to prevent, treat, or cure an HIV-1 infection. For example, one variant neutralized HIV-1 most efficiently, while others best enlisted natural killer cells to eliminate infected cells. These observations will help generate eCD4-Ig variants optimized for different clinical applications.

Nueva clasificación de las histiocitosis / New classification of histiocytosis

No disponible

eCD4-Ig promotes ADCC activity of sera from HIV-1-infected patients.

Antibody-dependent cell-mediated cytotoxity (ADCC) can eliminate HIV-1 infected cells, and may help reduce the reservoir of latent virus in infected patients. Sera of HIV-1 positive individuals include a number of antibodies that recognize epitopes usually occluded on HIV-1 envelope glycoprotein (Env) trimers. We have recently described eCD4-Ig, a potent and exceptionally broad inhibitor of HIV-1 entry that can be used to protect rhesus macaques from multiple high-dose challenges with simian-human immunodeficiency virus AD8 (SHIV-AD8). Here we show that eCD4-Ig bearing an IgG1 Fc domain (eCD4-IgG1) can mediate efficient ADCC activity against HIV-1 isolates with differing tropisms, and that it does so at least 10-fold more efficiently than CD4-Ig, even when more CD4-Ig molecules bound cell surface-expressed Env. An ADCC-inactive IgG2 form of eCD4-Ig (eCD4-IgG2) exposes V3-loop and CD4-induced epitopes on cell-expressed trimers, and renders HIV-1-infected cells susceptible to ADCC mediated by antibodies of these classes. Moreover, eCD4-IgG2, but not IgG2 forms of the broadly neutralizing antibodies VRC01 and 10-1074, enhances the ADCC activities of serum antibodies from patients by 100-fold, and significantly enhanced killing of two latently infected T-cell lines reactivated by vorinostat or TNFα. Thus eCD4-Ig is qualitatively different from CD4-Ig or neutralizing antibodies in its ability to mediate ADCC, and it may be uniquely useful in treating HIV-1 infection or reducing the reservoir of latently infected cells.

Seudotumor inflamatorio orbitario IgG4 asociado a aplasia etmoido-maxilar unilateral / IgG4 orbital inflammatory pseudotumor associated to unilateral ethmoid and maxillary sinus aplasia

No disponible

Afección del sistema nervioso central en la enfermedad relacionada con IgG4: descripción de un caso y revisión de la bibliografía / Central nervous system in IgG4-related disease: case report and literature review

Introducción. La enfermedad relacionada con IgG4 es una entidad clínica multisistémica recientemente descrita y que se presenta con diferentes manifestaciones clínicas. Los órganos que están afectados con mayor frecuencia son el páncreas, la vía biliar y las glándulas salivales, y es menos frecuente la afección del sistema nervioso central. Caso clínico. Mujer de 33 años con alteraciones cognitivas, alucinaciones, cefalea, síndrome convulsivo, sinusitis maxilar con afección ósea y evidencia de paquimeningitis y panhipopituitarismo, con biopsia meníngea que confirmó una enfermedad relacionada con IgG4, tras haberse descartado causas secundarias. Se inició tratamiento con glucocorticoides y azatioprina, sin recaídas después de 12 meses de seguimiento. Conclusiones. Se debe considerar el diagnóstico de enfermedad relacionada con IgG4 en casos de paquimeningitis hipertrófica e hipofisitis, incluso sin que se acompañen de otras manifestaciones sistémicas, siempre que se hayan descartado otras causas más frecuentes. El tratamiento de elección son los glucocorticoides, y puede ser necesario añadir otro inmunosupresor como ahorrador de esteroides y para evitar las recaídas. Se necesitan estudios prospectivos para evaluar las diferentes manifestaciones clínicas y paraclínicas y establecer los resultados del tratamiento a largo plazo (AU)

Introduction. IgG4-related disease is a recently described multisystemic clinical entity that can occur with different clinical manifestations. The most often affected organs are the pancreas, bile duct and salivary glands, with unusual central nervous system affection. Case Report. A 33 year old woman who presented with cognitive impairment, hallucinations, headache, convulsive syndrome, maxillary sinus inflammation with bone involvement and evidence of pachymeningitis and panhypopytuirarism with meningeal biopsy that confirmed IgG4-related disease, after ruling out secondary causes. Treatment was started with steroids and azathioprine without relapses after 12 months follow-up. Conclusions. IgG4-related disease should be considered in cases of hypertrophic pachymeningitis and hypophysitis especially when no other cause has been found, even if they are not accompanied by other systemic disease manifestations, having ruled out other common causes. The treatment of choice is glucocorticoids and it could be needed to add another immuno­suppressant agent as steroid sparing and to prevent relapses. Prospective studies are needed to evaluate the different clinical and paraclinical manifestations and to establish the results of long-term treatment (AU)

Pancreatitis autoinmune: a propósito de un caso / Autoimmune pancreatitis: a case report

La pancreatitis autoinmune (PAI) es una patología poco frecuente, aunque con una creciente incidencia en países orientales, si bien esto podría deberse a una mayor tasa de detección. Puede asociarse a otras patologías autoinmunes, y se ha descrito su asociación con la enfermedad sistémica por IgG4. La clínica es variada y el tratamiento habitualmente es médico, mediante corticoides. Se describe un caso clínico diagnosticado (AU)

Autoimmune pancreatitis (AIP) is an infrequent pathology, although there is a growing incidence in Eastern countries, which might be due to a greater rate of detection. It can be associated with other autoimmune pathologies and its association with IgG4-related systemic disease has been described. Its clinical presentation is varied and the normal treatment is medical, using corticoids. A diagnosed clinical case is described (AU)

Retroperitoneal IgG4-related sclerosing disease mimics renal pelvic cancer on 18F-FDG PET/CT / Enfermedad esclerosante retroperitoneal relacionada con IgG4 simulando un cáncer de pelvis renal en PET/TC 18F-FDG

No disponible

Fibrosis retroperitoneal relacionada con IgG4 / IgG4-Related Retroperitoneal fibrosis

OBJETIVO: Reportar dos nuevos casos de fibrosis retroperitoneal relacionada con IgG4, patología recientemente descrita. MÉTODO: Analizamos dos casos diagnosticados en nuestro centro y revisión de la literatura.RESULTADO: La enfermedad relacionada con IgG4 es una nueva entidad que agrupa diversas patologías fibroinflamatorias hasta ahora no relacionadas entre sí. Las manifestaciones clínicas son muy variables y la presentación suele ser subaguda. El tratamiento de elección son los corticoides. En el primer caso la evolución fue favorable con corticoides y azatioprina. En cambio, el segundo caso precisó cirugía en 2 ocasiones con nefrectomía radical. El diagnostico del segundo caso se realizó 9 años desde el inicio de los síntomas tras revisión de la biopsia; en ese momento no se inicio tratamiento inmunosupresor. CONCLUSIONES: Es muy importante conocerla y diagnosticarla dada la buena respuesta al tratamiento que evita complicaciones

OBJECTIVE: To report two new cases of IgG4-related retroperitoneal fibrosis, a recently described pathology. METHODS: We analyze two cases diagnosed in our center and performed a literature review. RESULT: IgG4 related disease is a recently described entity that includes previously not related pathologies. The clinical manifestations are highly variable and its presentation is usually subacute. The treatment of choice is glucocorticoids. In our first case the outcome was favorable with corticosteroids and azathioprine. However, the second case required surgery on 2 occasions with radical nephrectomy. The diagnosis of the latter was made nine years after the onset of symptoms when the biopsy was reviewed; at that moment immunosuppressive therapy was not started. CONCLUSIONS: It is very important to know and diagnose this disease because of the good response to treatment that prevents complications

Dose-response curve slope helps predict therapeutic potency and breadth of HIV broadly neutralizing antibodies.

A new generation of HIV broadly neutralizing antibodies (bnAbs) with remarkable potency, breadth and epitope diversity has rejuvenated interest in immunotherapeutic strategies. Potencies defined by in vitro IC50 and IC80 values (50 and 80% inhibitory concentrations) figure prominently into the selection of clinical candidates; however, much higher therapeutic levels will be required to reduce multiple logs of virus and impede escape. Here we predict bnAb potency at therapeutic levels by analysing dose-response curve slopes, and show that slope is independent of IC50/IC80 and specifically relates to bnAb epitope class. With few exceptions, CD4-binding site and V3-glycan bnAbs exhibit slopes >1, indicative of higher expected therapeutic effectiveness, whereas V2-glycan, gp41 membrane-proximal external region (MPER) and gp120-gp41 bnAbs exhibit less favourable slopes <1. Our results indicate that slope is one major predictor of both potency and breadth for bnAbs at clinically relevant concentrations, and may better coordinate the relationship between bnAb epitope structure and therapeutic expectations.

Long-term effect of sublingual and subcutaneous immunotherapy in dust mite–allergic children with asthma/rhinitis: a 3-year prospective randomized controlled trial

Background and Objective: Specific allergen immunotherapy is the only treatment modality that might change the natural course of allergic diseases in childhood. We sought to prospectively compare the long-term clinical and immunological effects of sublingual (SLIT) and subcutaneous (SCIT) immunotherapy compared with pharmacotherapy alone. Methods: In this single-center, prospective randomized controlled trial, 48 children with mild persistent asthma with/without rhinitis, monosensitized to house dust mites (HDMs) were followed for 3 years. At baseline and years 1 and 3 of follow-up, patients were evaluated and compared for total rhinitis (TRSS) and asthma (TASS) symptom scores, total symptom scores (TSS), total medication scores (TMS), safety profiles, skin-nasal-bronchial reactivity, and immunological parameters. Results: A significant reduction was observed in TASS for both HDM-SCIT and HDM-SLIT at year 3 of treatment compared with baseline and controls (P<.05 for both), with significant improvement in rhinitis symptoms for both groups compared with controls (P=.01 for both). TSS decreased significantly in both HDM-SCIT and HDM-SLIT at year 3 compared with baseline (P=.007 and P=.04, respectively) and controls (P<.01 for both). A significant reduction in TMS was observed in HDM-SCIT and HDM-SLIT compared with baseline and controls (P=.01 in all cases), with a reduction in skin reactivity to HDM (P<.05). Finally, a significant increase in allergen specific IgG4 was observed in the SCIT group at year 3 compared with baseline, the SLIT group, and controls (P<.001 in all cases). Conclusions: HDM-sensitized asthmatic children treated for at least 3 years with either SCIT or SLIT showed sustained clinical improvement (AU)

Antecedentes: La inmunoterapia con alérgenos es el único tratamiento que podría cambiar el curso natural evolutivo de las enfermedades alérgicas en la infancia. Nuestro objetivo era comparar, de manera prospectiva, la eficacia a largo plazo de la inmunoterapia sublingual (SLIT) y subcutánea (SCIT), con el tratamiento exclusivo con farmacoterapia convencional. Métodos:En este ensayo clínico, prospectivo de tres años de duración, realizado en un solo centro y aleatorizado, se incluyeron 48 niños con asma leve persistente, con o sin rinitis asociada, monosensibilizados a los ácaros del polvo (HDM). Los pacientes fueron evaluados al inicio, al año y a los tres años de tratamiento, comparándose los cambios en la puntuación de síntomas nasales (TRSS), bronquiales (TASS), puntuación total de síntomas (TSS) y consumo de medicación (TMS), perfil de seguridad, reactividad frente al alérgeno cutánea, nasal y bronquial y diversos parámetros inmunológicos. Resultados: Se observó una reducción significativa del TASS tanto para el grupo HDM-SCIT como HDM-SLIT al final del tercer año de tratamiento, tanto cuando se comparaba con la situación basal como con los cambios observados en el grupo control (p<0.05, respectivamente). El TRSS también mejoró significativamente en ambos grupos HDM-SCIT y HDM-SLIT en el tercer año de tratamiento, cuando los cambios se compararon con los observados en el grupo control (p=0,01, en ambos). El TSS y el TMS disminuyeron también significativamente en ambos grupos HDM-SCIT y HDM-SLIT en el tercer año, comparado con la situación basal (p=0,007, p=0,04/ p=0,01, p=0,01 respectivamente) y con el grupo control (p<0,01,p<0,01/ p=0,01, p=0,01, respectivamente). Tras tres años de tratamiento la reactividad cutánea frente a los alérgenos de los ácaros disminuyó significativamente (p<0,05). Los niveles de IgG4 específica frente a ácaros se incrementaron en el grupo SCIT-HDM, comparados con la situación basal y con los cambios observados en el grupo SLIT-HDM y control (p<0,001, respectivamente). Conclusiones: El tratamiento durante tres años con inmunoterapia específica tanto SCIT como SLIT se acompañó de una eficacia clínica sostenida, en este grupo de niños asmáticos sensibilizados a los ácaros del polvo. Ambas rutas de administración de la inmunoterapia parecen tener mecanismos de acción similares (AU)

Antibody conjugation approach enhances breadth and potency of neutralization of anti-HIV-1 antibodies and CD4-IgG.

Broadly neutralizing antibodies PG9 and PG16 effectively neutralize 70 to 80% of circulating HIV-1 isolates. In this study, the neutralization abilities of PG9 and PG16 were further enhanced by bioconjugation with aplaviroc, a small-molecule inhibitor of virus entry into host cells. A novel air-stable diazonium hexafluorophosphate reagent that allows for rapid, tyrosine-selective functionalization of proteins and antibodies under mild conditions was used to prepare a series of aplaviroc-conjugated antibodies, including b12, 2G12, PG9, PG16, and CD4-IgG. The conjugated antibodies blocked HIV-1 entry through two mechanisms: by binding to the virus itself and by blocking the CCR5 receptor on host cells. Chemical modification did not significantly alter the potency of the parent antibodies against nonresistant HIV-1 strains. Conjugation did not alter the pharmacokinetics of a model IgG in blood. The PG9-aplaviroc conjugate was tested against a panel of 117 HIV-1 strains and was found to neutralize 100% of the viruses. PG9-aplaviroc conjugate IC50s were lower than those of PG9 in neutralization studies of 36 of the 117 HIV-1 strains. These results support this new approach to bispecific antibodies and offer a potential new strategy for combining HIV-1 therapies.

Antibody gene transfer for HIV immunoprophylaxis.

Antibody gene transfer, which involves the delivery of genes that encode potent, broadly neutralizing antibodies to human immunodeficiency virus (HIV), is a promising new strategy for preventing HIV infection. A satellite symposium at the AIDS Vaccine 2012 conference brought together many of the groups working in this field.

SAXS data analysis and modeling of tetravalent neutralizing antibody CD4-IgG2 -/+ HIV-1 gp120 revealed that first two gp120 bind to the same Fab arm.

This communication describes SAXS data based global structures of tetravalent antibody CD4-IgG2 and its dimeric to pentameric complexes with gp120s. Comparison of models brought forth that while the two CD4s grafted on each arm remain tightly packed in the unliganded antibody, they enable binding of first two gp120s preferentially to the same Fab arm in an asymmetric manner. Retention of residues in the CD4-Fab linker earlier reasoned to enable bi-fold collapse of gp120-bound soluble CD4, and observed asymmetry of the (CD4-IgG2)/(gp120)(2) complex suggest that encoded flexibility in CD4-Fab linker is a critical structure-function factor for this broad spectrum neutralizing antibody.

Vector-mediated gene transfer engenders long-lived neutralizing activity and protection against SIV infection in monkeys.

The key to an effective HIV vaccine is development of an immunogen that elicits persisting antibodies with broad neutralizing activity against field strains of the virus. Unfortunately, very little progress has been made in finding or designing such immunogens. Using the simian immunodeficiency virus (SIV) model, we have taken a markedly different approach: delivery to muscle of an adeno-associated virus gene transfer vector expressing antibodies or antibody-like immunoadhesins having predetermined SIV specificity. With this approach, SIV-specific molecules are endogenously synthesized in myofibers and passively distributed to the circulatory system. Using such an approach in monkeys, we have now generated long-lasting neutralizing activity in serum and have observed complete protection against intravenous challenge with virulent SIV. In essence, this strategy bypasses the adaptive immune system and holds considerable promise as a unique approach to an effective HIV vaccine.

ICOS/B7RP-1 interference in mouse kidney transplantation.

BACKGROUND: Activated T cells play a key role in allograft rejection. T cell activation requires signaling via the T cell receptor as well as costimulatory signals. Inducible costimulatory molecule (ICOS), with its ligand B7RP-1, is a recently discovered costimulatory molecule of the CD28 family. The role of this signaling pathway during the early phases of kidney allograft rejection is not clear so far. METHODS: Kidneys were orthotopically transplanted from BALB/c to C57BL/6 mice. Animals were assigned to five experimental groups: blocking anti-ICOS monoclonal antibody, ICOS fusion protein, anti-B7RP1 monoclonal antibody, B7RP-1 fusion protein, and control immunoglobulin G. RESULTS: Survival was significantly reduced in animals treated with ICOS monoclonal antibody (mAb) and B7RP-1 Fc as compared with controls. These animals had also a lower number of apoptotic graft infiltrating T cells, whereas the expression of intracellular interferon-gamma in CD3CD4 T cells was increased. Animals treated with ICOS Fc and B7RP-1 mAb had similar survival and numbers of apoptotic T cells as compared with controls. CONCLUSIONS: In summary, the blockade of ICOS with ICOS mAb or B7RP-1 Fc reduced the amount of apoptosis of infiltrating lymphocytes and resulted in continuous inflammatory processes with progressive tissue damage and graft failure.

Specific amino acids in the N-terminus of the gp41 ectodomain contribute to the stabilization of a soluble, cleaved gp140 envelope glycoprotein from human immunodeficiency virus type 1.

The HIV-1 envelope glycoprotein is expressed on the viral membrane as a trimeric complex, formed by three gp120 surface glycoproteins non-covalently associated with three membrane-anchored gp41 subunits. The labile nature of the association between gp120 and gp41 hinders the expression of soluble, fully cleaved, trimeric gp140 proteins for structural and immunization studies. Disruption of the primary cleavage site within gp160 allows the production of stable gp140 trimers, but cleavage-defective trimers are antigenically dissimilar from their cleaved counterparts. Soluble, stabilized, proteolytically cleaved, trimeric gp140 proteins can be generated by engineering an intermolecular disulfide bond between gp120 and gp41 (SOS), combined with a single residue change, I559P, within gp41 (SOSIP). We have found that SOSIP gp140 proteins based on the subtype A HIV-1 strain KNH1144 form particularly homogenous trimers compared to a prototypic strain (JR-FL, subtype B). We now show that the determinants of this enhanced stability are located in the N-terminal region of KNH11144 gp41 and that, when substituted into heterologous Env sequences (e.g., JR-FL and Ba-L) they have a similarly beneficial effect on trimer stability. The stabilized trimers retain the epitopes for several neutralizing antibodies (b12, 2G12, 2F5 and 4E10) and the CD4-IgG2 molecule, suggesting that the overall antigenic structure of the gp140 protein has not been adversely impaired by the trimer-stabilizing substitutions. The ability to increase the stability of gp140 trimers might be useful for neutralizing antibody-based vaccine strategies based on the use of this type of immunogen.

Epigallocatechin gallate, the main polyphenol in green tea, binds to the T-cell receptor, CD4: Potential for HIV-1 therapy.

BACKGROUND: The green tea flavonoid, epigallocatechin gallate (EGCG), has been proposed to have an anti-HIV-1 effect by preventing the binding of HIV-1 glycoprotein (gp) 120 to the CD4 molecule on T cells. OBJECTIVE: To demonstrate that EGCG binds to the CD4 molecule at the gp120 attachment site and inhibits gp120 binding at physiologically relevant levels, thus establishing EGCG as a potential therapeutic treatment for HIV-1 infection. METHODS: Nuclear magnetic resonance spectroscopy was used to examine the binding of EGCG and control, (-)-catechin, to CD4-IgG2 (PRO 542). Gp120 binding to human CD4+ T cells was analyzed by flow cytometry. RESULTS: Addition of CD4 to EGCG produced a linear decrease in nuclear magnetic resonance signal intensity from EGCG but not from the control, (-)-catechin. In saturation transfer difference experiments, addition of 5.8 micromol/L CD4 to 310 micromol/L EGCG produced strong saturation at the aromatic rings of EGCG, but identical concentrations of (-)-catechin produced much smaller effects, implying EGCG/CD4 binding strong enough to reduce gp120/CD4 binding substantially. Molecular modeling studies suggested a binding site for EGCG in the D1 domain of CD4, the pocket that binds gp120. Physiologically relevant concentrations of EGCG (0.2 micromol/L) inhibited binding of gp120 to isolated human CD4+ T cells. CONCLUSION: We have demonstrated clear evidence of high-affinity binding of EGCG to the CD4 molecule with a Kd of approximately 10 nmol/L and inhibition of gp120 binding to human CD4+ T cells. CLINICAL IMPLICATIONS: Epigallocatechin gallate has potential use as adjunctive therapy in HIV-1 infection.