scholarly journals Susceptibility to neutralization by bnAbs orrelates with infected cell binding for a panel of clade B HIV reactivated from latent reservoirs

2017 ◽  
Vol 3 ◽  
pp. 32-33
Author(s):  
Y. Ren ◽  
M. Korom ◽  
R. Truong ◽  
Szu-Han Huang ◽  
D. Chan ◽  
...  
Keyword(s):  
Infected Cell ◽  
Cell Binding ◽  
Clade B

scholarly journals Susceptibility to Neutralization by Broadly Neutralizing Antibodies Generally Correlates with Infected Cell Binding for a Panel of Clade B HIV Reactivated from Latent Reservoirs

2018 ◽  
Vol 92 (23) ◽  
Author(s):  
Yanqin Ren ◽  
Maria Korom ◽  
Ronald Truong ◽  
Dora Chan ◽  
Szu-Han Huang ◽  
...  
Keyword(s):  
T Cells ◽  
Infected Cell ◽  
Neutralizing Antibodies ◽  
Binding Assays ◽  
Cell Binding ◽  
Broadly Neutralizing Antibodies ◽  
Clade B ◽  
Latently Infected ◽  
Living With Hiv ◽  
Selection Of

ABSTRACTEfforts to cure human immunodeficiency virus (HIV) infection are obstructed by reservoirs of latently infected CD4+T cells that can reestablish viremia. HIV-specific broadly neutralizing antibodies (bNAbs), defined by unusually wide neutralization breadths against globally diverse viruses, may contribute to the elimination of these reservoirs by binding to reactivated cells, thus targeting them for immune clearance. However, the relationship between neutralization of reservoir isolates and binding to corresponding infected primary CD4+T cells has not been determined. Thus, the extent to which neutralization breadths and potencies can be used to infer the corresponding parameters of infected cell binding is currently unknown. We assessed the breadths and potencies of bNAbs against 36 viruses reactivated from peripheral blood CD4+T cells from antiretroviral (ARV)-treated HIV-infected individuals by using paired neutralization and infected cell binding assays. Single-antibody breadths ranged from 0 to 64% for neutralization (80% inhibitory concentration [IC80] of ≤10 μg/ml) and from 0 to 89% for binding, with two-antibody combinations (results for antibody combinations are theoretical/predicted) reaching levels of 0 to 83% and 50 to 100%, respectively. Infected cell binding correlated with virus neutralization for 10 of 14 antibodies (e.g., for 3BNC117,r = 0.82 andP < 0.0001). Heterogeneity was observed, however, with a lack of significant correlation for 2G12, CAP256.VRC26.25, 2F5, and 4E10. Our results provide guidance on the selection of bNAbs for interventional cure studies, both by providing a direct assessment of intra- and interindividual variabilities in neutralization and infected cell binding in a novel cohort and by defining the relationships between these parameters for a panel of bNAbs.IMPORTANCEAlthough antiretroviral therapies have improved the lives of people who are living with HIV, they do not cure infection. Efforts are being directed towards harnessing the immune system to eliminate the virus that persists, potentially resulting in virus-free remission without medication. HIV-specific antibodies hold promise for such therapies owing to their ability to both prevent the infection of new cells (neutralization) and direct the killing of infected cells. We isolated 36 HIV strains from individuals whose virus was suppressed by medication and tested 14 different antibodies for neutralization of these viruses and for binding to cells infected with the same viruses (critical for engaging natural killer cells). For both neutralization and infected cell binding, we observed variation both between individuals and amongst different viruses within an individual. For most antibodies, neutralization activity correlated with infected cell binding. These data provide guidance on the selection of antibodies for clinical trials.

scholarly journals Susceptibility to Neutralization by Broadly Neutralizing Antibodies Correlates with Infected Cell Binding for a Panel of Clade B HIV Reactivated from Latent Reservoirs

2018 ◽  
Author(s):  
Yanqin Ren ◽  
Maria Korom ◽  
Ronald Truong ◽  
Dora Chan ◽  
Szu-han Huang ◽  
...  
Keyword(s):  
T Cells ◽  
Infected Cell ◽  
Neutralizing Antibodies ◽  
Individual Variability ◽  
Binding Assays ◽  
Cell Binding ◽  
Specific Antibodies ◽  
Clade B ◽  
Latently Infected ◽  
Selection Of

AbstractEfforts to HIV cure are obstructed by reservoirs of latently infected CD4+T-cells that can re-establish viremia. Broadly neutralizing HIV-specific antibodies (bNAbs), defined by unusually high neutralization breadths against globally diverse viruses, may contribute to the elimination of these reservoirs by binding to reactivated cells, targeting them for immune clearance. However, the relationship between neutralization of reservoir isolates and binding to corresponding infected primary CD4+T-cells has not been determined. Thus, the extent to which neutralization breadths and potencies can be used to infer the corresponding parameters of infected-cell binding is currently unknown. We assessed the breadths and potencies of bNAbs against 36 viruses reactivated from peripheral blood CD4+T-cells of ARV-treated HIV-infected individuals, using paired neutralization and infected-cell binding assays. Single antibody breadths ranged from 0–64% for neutralization (IC80≤10μg/ml) and 0–89% for binding, with two-antibody combinations reaching 0-83% and 50-100%, respectively. Infected-cell binding correlated with virus neutralization for 10 out of 14 antibodies (e.g. 3BNC117, r=0.87, p<0.0001). Heterogeneity was observed, however, with a lack of significant correlations for 2G12, CAP256.VRC26.25, 2F5, and 4E10. Our results provide guidance on the selection of bNAbs for interventional cure studies; both by providing a direct assessment of intra-and inter-individual variability in neutralization and infected cell binding in a novel cohort, and by defining the relationships between these parameters for a panel of bNAbs.ImportanceAlthough anti-retroviral therapies have improved the lives of people who are living with HIV, they do not cure infection. Efforts are being directed towards harnessing the immune system to eliminate the virus that persists, potentially resulting in virus-free remission without medication. HIV-specific antibodies hold promise for such therapies owing to their abilities to both prevent the infection of new cells (neutralization), and also to direct the killing of infected cells. We isolated 36 HIV strains from individuals whose virus was suppressed by medication, and tested 14 different antibodies for neutralization of these viruses and for binding to cells infected with the same viruses (critical for engaging natural killer cells). For both neutralization and infected-cell binding, we observed variation both between individuals, and amongst different viruses within an individual. For most antibodies, neutralization activity correlated with infected cell binding. These data provide guidance on the selection of antibodies for clinical trials.

scholarly journals In vitro rosetting, cytoadherence, and microagglutination properties of Plasmodium falciparum-infected erythrocytes from Gambian and Tanzanian patients

Blood ◽  
1990 ◽  
Vol 76 (9) ◽  
pp. 1845-1852 ◽  
Author(s):  
T Hasler ◽  
SM Handunnetti ◽  
JC Aguiar ◽  
MR van Schravendijk ◽  
BM Greenwood ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Infected Cell ◽  
Blood Cells ◽  
Molecular Mechanisms ◽  
Melanoma Cells ◽  
Schizont Stage ◽  
Ring Stage ◽  
Cell Binding ◽  
Blood Samples

Abstract To understand the molecular mechanisms that lead to sequestration of red blood cells infected with mature stages of Plasmodium falciparum and to examine the relevance of earlier studies on adherence properties of laboratory-derived P falciparum parasites to the natural parasite population, we analyzed Gambian and Tanzanian isolates for in vitro cytoadherence and antibody-mediated microagglutination. Eighteen cryopreserved isolates of ring-stage parasites were cultured for 20 to 30 hours in vitro, in the patients original erythrocytes, to the trophozoite and schizont stage. All parasites were positive in the microagglutination assay with at least one of four African hyperimmune sera. In a rosetting assay, only 2 of the 18 isolates were strongly positive (35% and 41% of parasitized erythrocytes with more than two uninfected cells bound). Thirteen isolates showed either intermediate (5% to 18%) or low (less than 5%) rosetting while three isolates did not form rosettes. Infected cell-binding of the different isolates to immobilized CD36 or thrombospondin, or C32 melanoma cells correlated with the percentage of mature parasites in the blood samples (r = .932 for CD36, r = .946 for thrombospondin, and r = .881 for C32 melanoma cells). There was a high correlation between binding to CD36 and thrombospondin (r = .982). The extent of infected cell rosetting with uninfected cells in these blood samples was not correlated with these other receptor properties. We also observed coexpression of rosetting and cytoadherence receptors on the same parasitized erythrocytes.

scholarly journals In vitro rosetting, cytoadherence, and microagglutination properties of Plasmodium falciparum-infected erythrocytes from Gambian and Tanzanian patients

Blood ◽  
1990 ◽  
Vol 76 (9) ◽  
pp. 1845-1852
Author(s):  
T Hasler ◽  
SM Handunnetti ◽  
JC Aguiar ◽  
MR van Schravendijk ◽  
BM Greenwood ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Infected Cell ◽  
Blood Cells ◽  
Molecular Mechanisms ◽  
Melanoma Cells ◽  
Schizont Stage ◽  
Ring Stage ◽  
Cell Binding ◽  
Blood Samples

To understand the molecular mechanisms that lead to sequestration of red blood cells infected with mature stages of Plasmodium falciparum and to examine the relevance of earlier studies on adherence properties of laboratory-derived P falciparum parasites to the natural parasite population, we analyzed Gambian and Tanzanian isolates for in vitro cytoadherence and antibody-mediated microagglutination. Eighteen cryopreserved isolates of ring-stage parasites were cultured for 20 to 30 hours in vitro, in the patients original erythrocytes, to the trophozoite and schizont stage. All parasites were positive in the microagglutination assay with at least one of four African hyperimmune sera. In a rosetting assay, only 2 of the 18 isolates were strongly positive (35% and 41% of parasitized erythrocytes with more than two uninfected cells bound). Thirteen isolates showed either intermediate (5% to 18%) or low (less than 5%) rosetting while three isolates did not form rosettes. Infected cell-binding of the different isolates to immobilized CD36 or thrombospondin, or C32 melanoma cells correlated with the percentage of mature parasites in the blood samples (r = .932 for CD36, r = .946 for thrombospondin, and r = .881 for C32 melanoma cells). There was a high correlation between binding to CD36 and thrombospondin (r = .982). The extent of infected cell rosetting with uninfected cells in these blood samples was not correlated with these other receptor properties. We also observed coexpression of rosetting and cytoadherence receptors on the same parasitized erythrocytes.

Further Observations on the Virus of Epizootic Diarrhea of Infant Mice. An Electron Microscopic Study

1967 ◽  
Vol 25 ◽  
pp. 110-111
Author(s):  
W. G. Banfield ◽  
G. Kasnic ◽  
J. H. Blackwell
Keyword(s):  
Electron Microscope ◽  
Infected Cell ◽  
Microscopic Study ◽  
Intestinal Epithelium ◽  
Ultrastructural Study ◽  
Osmium Tetroxide ◽  
Lead Citrate ◽  
Electron Microscopic ◽  
Virus Particles ◽  
Infected Cells

An ultrastructural study of the intestinal epithelium of mice infected with the agent of epizootic diarrhea of infant mice (EDIM virus) was first performed by Adams and Kraft. We have extended their observations and have found developmental forms of the virus and associated structures not reported by them.Three-day-old NLM strain mice were infected with EDIM virus and killed 48 to 168 hours later. Specimens of bowel were fixed in glutaraldehyde, post fixed in osmium tetroxide and embedded in epon. Sections were stained with uranyl magnesium acetate followed by lead citrate and examined in an updated RCA EMU-3F electron microscope.The cells containing virus particles (infected) are at the tips of the villi and occur throughout the intestine from duodenum through colon. All developmental forms of the virus are present from 48 to 168 hours after infection. Figure 1 is of cells without virus particles and figure 2 is of an infected cell. The nucleus and cytoplasm of the infected cells appear clearer than the cells without virus particles.

In Vitro and in Vivo Comparison of Binding of 99m-Tc-Iabeled Anti-CEA MAb F33-104 with 99m-Tc-labeled Anti-CEA MAb BW431/26

1999 ◽  
Vol 38 (04) ◽  
pp. 115-119
Author(s):  
N. Oriuchi ◽  
S. Sugiyama ◽  
M. Kuroki ◽  
Y. Matsuoka ◽  
S. Tanada ◽  
...  
Keyword(s):  
Nude Mice ◽  
Binding Capacity ◽  
Colon Adenocarcinoma ◽  
Human Colon ◽  
Cell Binding ◽  
Vitro Binding ◽  
Labeling Method ◽  
Human Colon Adenocarcinoma

Summary Aim: The purpose of this study was to assess the potential for radioimmunodetection (RAID) of murine anti-carcinoembryonic antigen (CEA) monoclonal antibody (MAb) F33-104 labeled with technetium-99m (99m-Tc) by a reduction-mediated labeling method. Methods: The binding capacity of 99m-Tc-labeled anti-CEA MAb F33-104 with CEA by means of in vitro procedures such as immunoradiometric assay and cell binding assay and the biodistribution of 99m-Tc-labeled anti-CEA MAb F33-104 in normal nude mice and nude mice bearing human colon adenocarcinoma LS180 tumor were investigated and compared with 99m-Tc-labeled anti-CEA MAb BW431/26. Results: The in vitro binding rate of 99m-Tc-labeled anti-CEA MAb F33-104 with CEA in solution and attached to the cell membrane was significantly higher than 99m-Tclabeled anti-CEA MAb BW431/261 (31.4 ± 0.95% vs. 11.9 ± 0.55% at 100 ng/mL of soluble CEA, 83.5 ± 2.84% vs. 54.0 ± 2.54% at 107 of LS 180 cells). In vivo, accumulation of 99m-Tc-labeled anti-CEA MAb F33-104 was higher at 18 h postinjection than 99m-Tc-labeled anti-CEA MAb BW431/26 (20.1 ± 3.50% ID/g vs. 14.4 ± 3.30% ID/g). 99m-Tcactivity in the kidneys of nude mice bearing tumor was higher at 18 h postinjection than at 3 h (12.8 ± 2.10% ID/g vs. 8.01 ± 2.40% ID/g of 99m-Tc-labeled anti-CEA MAb F33-104, 10.7 ± 1.70% ID/g vs. 8.10 ± 1.75% ID/g of 99m-Tc-labeled anti-CEA MAb BW431/26). Conclusion: 99m-Tc-labeled anti-CEA MAb F33-104 is a potential novel agent for RAID of recurrent colorectal cancer.

High Affinity Binding Sites for Activated Protein C and Protein C on Cultured Human Umbilical Vein Endothelial Cells

1994 ◽  
Vol 72 (03) ◽  
pp. 465-474 ◽  
Author(s):  
Neelesh Bangalore ◽  
William N Drohan ◽  
Carolyn L Orthner
Keyword(s):  
Binding Sites ◽  
Protein C ◽  
Umbilical Vein ◽  
Activated Protein C ◽  
Affinity Binding ◽  
Cell Binding ◽  
High Affinity Binding ◽  
High Affinity ◽  
Gla Domain ◽  
Umbilical Vein Endothelial Cells

SummaryActivated protein C (APC) is an antithrombotic serine proteinase having anticoagulant, profibrinolytic and anti-inflammatory activities. Despite its potential clinical utility, relatively little is known about its clearance mechanisms. In the present study we have characterized the interaction of APC and its active site blocked forms with human umbilical vein endothelial cells (HUVEC). At 4° C 125I-APC bound to HUVEC in a specific, time dependent, saturable and reversible manner. Scatchard analysis of the binding isotherm demonstrated a Kd value of 6.8 nM and total number of binding sites per cell of 359,000. Similar binding isotherms were obtained using radiolabeled protein C (PC) zymogen as well as D-phe-pro-arg-chloromethylketone (PPACK) inhibited APC indicating that a functional active site was not required. Competition studies showed that the binding of APC, PPACK-APC and PC were mutually exclusive suggesting that they bound to the same site(s). Proteolytic removal of the N-terminal γ-carboxyglutamic acid (gla) domain of PC abolished its ability to compete indicating that the gla-domain was essential for cell binding. Surprisingly, APC binding to these cells appeared to be independent of protein S, a cofactor of APC generally thought to be required for its high affinity binding to cell surfaces. The identity of the cell binding site(s), for the most part, appeared to be distinct from other known APC ligands which are associated with cell membranes or extracellular matrix including phospholipid, thrombomodulin, factor V, plasminogen activator inhibitor type 1 (PAI-1) and heparin. Pretreatment of HUVEC with antifactor VIII antibody caused partial inhibition of 125I-APC binding indicating that factor VIII or a homolog accounted for ∼30% of APC binding. Studies of the properties of surface bound 125I-APC or 125I-PC and their fate at 4°C compared to 37 °C were consistent with association of ∼25% of the initially bound radioligand with an endocytic receptor. However, most of the radioligand appeared not to be bound to an endocytic receptor and dissociated rapidly at 37° C in an intact and functional state. These data indicate the presence of specific, high affinity binding sites for APC and PC on the surface of HUVEC. While a minor proportion of binding sites may be involved in endocytosis, the identity and function of the major proportion is presently unknown. It is speculated that this putative receptor may be a further mechanisms of localizing the PC antithrombotic system to the vascular endothelium.

Polyfunctional CD8+ T-Cell Response to Autologous Peptides from Protease and Reverse Transcriptase of HIV-1 Clade B

2019 ◽  
Vol 17 (5) ◽  
pp. 350-359
Author(s):  
Liliana Acevedo-Saenz ◽  
Federico Perdomo-Celis ◽  
Carlos J. Montoya ◽  
Paula A. Velilla
Keyword(s):  
T Cell ◽  
Reverse Transcriptase ◽  
Cellular Response ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
Effective Vaccine ◽  
Cell Responses ◽  
Clade B ◽  
Hiv 1

Background: : The diversity of the HIV proteome influences the cellular response and development of an effective vaccine, particularly due to the generation of viral variants with mutations located within CD8+ T-cell epitopes. These mutations can affect the recognition of the epitopes, that may result in the selection of HIV variants with mutated epitopes (autologous epitopes) and different CD8+ T-cell functional profiles. Objective:: To determine the phenotype and functionality of CD8+ T-cell from HIV-infected Colombian patients in response to autologous and consensus peptides derived from HIV-1 clade B protease and reverse transcriptase (RT). Methods:: By flow cytometry, we compared the ex vivo CD8+ T-cell responses from HIV-infected patients to autologous and consensus peptides derived from HIV-1 clade B protease and RT, restricted by HLA-B*35, HLA-B*44 and HLA-B*51 alleles. Results:: Although autologous peptides restricted by HLA-B*35 and HLA-B*44 did not show any differences compared with consensus peptides, we observed the induction of a higher polyfunctional profile of CD8+ T-cells by autologous peptides restricted by HLA-B*51, particularly by the production of interferon-γ and macrophage inflammatory protein-1β. The response by different memory CD8+ T-cell populations was comparable between autologous vs. consensus peptides. In addition, the magnitude of the polyfunctional response induced by the HLA-B*51-restricted QRPLVTIRI autologous epitope correlated with low viremia. Conclusion:: Autologous peptides should be considered for the evaluation of HIV-specific CD8+ Tcell responses and to reveal some relevant epitopes that could be useful for therapeutic strategies aiming to promote polyfunctional CD8+ T-cell responses in a specific population of HIV-infected patients.

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