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48 total notes.
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C11: This review on antibody mediated cellular cytotoxicity (ADCC) effector functions of anti-HIV-1 antibodies discusses the association between the conformational state of HIV antigen, Env, and binding of either bnAbs or nnAbs (non-neutralizing antibodies) to it and their consequent Fc-mediated ADCC. While bnAbs tend to recognize the 'closed' trimeric State 1 conformation of Env, nnAbs and HIV+ sera bind States 2 and 3 of Env brought to its open conformation by interaction with the host CD4 molecule. Nef/Vpu-induced down regulation of membrane-bound CD4 (and also HLA, Env, BST-2, and NKG2DL) in HIV-infected cells therefore keeps Env in State 1 and these cells, reminiscent of the HIV latent reservoir, are susceptible to bnAb neutralization as well as ADCC. The use of CD4 mimetics (CD4mc), however, can mimic the interaction of CD4 with Env and bring it to its open, nnAb-binding state, after successive exposure of conserved epitopes in the coreceptor binding site (CoRBS) and anti cluster A to nnAbs. Therefore different ADCC-measuring assays are discussed with particular reference to the target cell being either HIV-infected and conducive to bnAb measurements or Env gp120 coated and a measure of nnAb ADCC. The inaccuracies introduced by bystander un-infected cells exposed to shed gp120 are also discussed. Antibodies A32, C11, N5i5 and 2.2c bind to the CD4-induced cluster A epitope on Env. While bnAbs VRC01, 3BNC117, PGT151, 8ANC195, PG9, PG16, PGT121, PGT126 have different binding regions all on closed State 1 of Env and elicit ADCC, the MPER set of 10E8, 4E10 and 2F5 recognize State 1 but do not result in potent ADCC. Studies have shown that some CD4BS bnAbs like b12 protect macaques from SHIV challenge, and 3BNC117 control HIV replication in humanized mice.
Richard2018
(CD4+ CTL, class I down-regulation by Nef, co-receptor, effector function, review)
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C11: This study assessed the ADCC activity of antibodies of varied binding types, including CD4bs (b6, b12, VRC01, PGV04, 3BNC117), V2 (PG9, PG16), V3 (PGT126, PGT121, 10-1074), oligomannose (2G12), MPER (2F5, 4E10, 10E8), CD4i (17b, X5), C1/C5 (A32, C11), cluster I (240D, F240), and cluster II (98-6, 126-7). ADCC activity was correlated with binding to Env on the surfaces of virus-infected cells. ADCC was correlated with neutralization, but not always for lab-adapted viruses such as HIV-1 NLA-3.
vonBredow2016
(effector function)
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C11: A highly conserved mechanism of exposure of ADCC epitopes on Env is reported, showing that binding of Env and CD4 within the same HIV-1 infected cell effectively exposes these epitopes. The mechanism might explain the evolutionary advantage of downregulation of cell surface CD4v by the Vpu and Nef proteins. C11 was used in co-expression assay to understand the conformational changes in Env upon CD4 binding. The interaction of A32, C11 and RV144 MAbs with Env was greatly increased upon coexpression of CD4 in a dose dependent manner.
Veillette2014
(effector function)
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C11: The complexity of the epitopes recognized by ADCC responses in HIV-1 infected individuals and candidate vaccine recipients is discussed in this review. C11 is discussed as the CD4i Cluster A region-targeting, non-neutralizing anti-gp120 mAb with a discontinuous epitope, exhibiting broad and prototypic ADCC activity similar to A32 (Table-1). It is reported that C11- and A32-blockable mAbs most likely recognize conformational epitopes within the inner domain of gp120 involving the C1 region.
Pollara2013
(effector function, review)
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C11: ADCC mediated by CD4i mAbs (or anti-CD4i-epitope mAbs) was studied using a panel of 41 novel mAbs. Three epitope clusters were classified, depending on cross-blocking in ELISA by different mAbs: Cluster A - in the gp120 face, cross-blocking by mAbs A32 and/or C11; Cluster B - in the region proximal to CoRBS (co-receptor binding site) involving V1V2 domain, cross-blocking by E51-M9; Cluster C - CoRBS, cross-blocking by 17b and/or 19e. The ADCC half-maximal effective concentrations of the Cluster A and B mAbs were generally 0.5-1 log lower than those of the Cluster C mAbs, and none of the Cluster A or B mAbs could neutralize HIV-1. Cluster A's A32- and C11-blockable mAbs were suggested to recognize conformational epitopes within the inner domain of gp120 that involve the C1 region. Neutralization potency and breadth were also assessed for these mAbs. No correlation was found between ADCC and neutralization Abs' action or functional responses. C11 was used as the positive control in different assays, especially competition ELISA assays to determine epitope specificity.
Guan2013
(antibody interactions, effector function)
References
Showing 5 matching of
49 total references.
Guan2013
Yongjun Guan, Marzena Pazgier, Mohammad M. Sajadi, Roberta Kamin-Lewis, Salma Al-Darmarki, Robin Flinko, Elena Lovo, Xueji Wu, James E. Robinson, Michael S. Seaman, Timothy R. Fouts, Robert C. Gallo, Anthony L. DeVico, and George K. Lewis. Diverse Specificity and Effector Function Among Human Antibodies to HIV-1 Envelope Glycoprotein Epitopes Exposed by CD4 Binding. Proc. Natl. Acad. Sci. U.S.A., 110(1):E69-E78, 2 Jan 2013. PubMed ID: 23237851.
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Pollara2013
Justin Pollara, Mattia Bonsignori, M. Anthony Moody, Marzena Pazgier, Barton F. Haynes, and Guido Ferrari. Epitope Specificity of Human Immunodeficiency Virus-1 Antibody Dependent Cellular Cytotoxicity (ADCC) Responses. Curr. HIV Res., 11(5):378-387, Jul 2013. PubMed ID: 24191939.
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Veillette2014
Maxime Veillette, Anik Désormeaux, Halima Medjahed, Nour-Elhouda Gharsallah, Mathieu Coutu, Joshua Baalwa, Yongjun Guan, George Lewis, Guido Ferrari, Beatrice H. Hahn, Barton F. Haynes, James E. Robinson, Daniel E. Kaufmann, Mattia Bonsignori, Joseph Sodroski, and Andres Finzi. Interaction with Cellular CD4 Exposes HIV-1 Envelope Epitopes Targeted by Antibody-Dependent Cell-Mediated Cytotoxicity. J. Virol., 88(5):2633-2644, Mar 2014. PubMed ID: 24352444.
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vonBredow2016
Benjamin von Bredow, Juan F. Arias, Lisa N. Heyer, Brian Moldt, Khoa Le, James E. Robinson, Susan Zolla-Pazner, Dennis R. Burton, and David T. Evans. Comparison of Antibody-Dependent Cell-Mediated Cytotoxicity and Virus Neutralization by HIV-1 Env-Specific Monoclonal Antibodies. J. Virol., 90(13):6127-6139, 1 Jul 2016. PubMed ID: 27122574.
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Richard2018
Jonathan Richard, Jeremie Prevost, Nirmin Alsahafi, Shilei Ding, and Andres Finzi. Impact of HIV-1 Envelope Conformation on ADCC Responses. Trends Microbiol, 26(4):253-265 doi, Apr 2018. PubMed ID: 29162391
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