Browsing by Author "Tumba, Nancy Lola."

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Amino acid changes in the HIV-1 gp41 membrane proximal region control virus neutralization sensitivity.
(Elsevier., 2016) Bradley, Todd.; Trama, Ashley.; Tumba, Nancy Lola.; Gray, Elin Solomonovna.; Lu, Xiaozhi.; Madani, Navid.; Jahanbakhsh, Fatemeh.; Eaton, Amanda.; Xia, Shi-Mao.; Parks, Robert.; Lloyd, Krissey E.; Sutherland, Laura L.; Scearce, Richard M.; Bowman, Cindy M.; Barnett, Susan.; Abdool Karim, Salim Safurdeen.; Boyd, Scott D.; Melillo, Bruno.; Smith, Amos B.; Sodroski, Joseph.; Kepler, Thomas B.; Alam, Shabnam Munir.; Gao, Feng.; Bonsignori, Mattia.; Liao, Hua-Xin.; Moody, Michael Anthony.; Montefiori, David Charles.; Santra, Sampa.; Morris, Lynn.; Haynes, Barton F.
Abstract available in pdf.
Evolution of an HIV glycan–dependent broadly neutralizing antibody epitope through immune escape.
(Nature Publishing Group., 2012) Moore, Penelope L.; Gray, Elin Solomonovna.; Wibmer, Constantinos Kurt.; Bhiman, Jinal N.; Nonyane, Molati.; Hermanus, Tandile.; Sheward, Daniel J.; Bajimaya, Shringkhala.; Abrahams, Melissa-Rose.; Tumba, Nancy Lola.; Ping, Li-Hua.; Ngandu, Nobubelo K.; Abdool Karim, Quarraisha.; Abdool Karim, Salim Safurdeen.; Swanstrom, Ronald.; Seaman, Michael S.; Williamson, Carolyn.; Morris, Lynn.;
Neutralizing antibodies are likely to play a crucial part in a preventative HIV-1 vaccine. Although efforts to elicit broadly cross-neutralizing (BCN) antibodies by vaccination have been unsuccessful, a minority of individuals naturally develop these antibodies after many years of infection. How such antibodies arise, and the role of viral evolution in shaping these responses, is unknown. Here we show, in two HIV-1–infected individuals who developed BCN antibodies targeting the glycan at Asn332 on the gp120 envelope, that this glycan was absent on the initial infecting virus. However, this BCN epitope evolved within 6 months, through immune escape from earlier strain-specific antibodies that resulted in a shift of a glycan to position 332. Both viruses that lacked the glycan at amino acid 332 were resistant to the Asn332-dependent BCN monoclonal antibody PGT128 (ref. 8), whereas escaped variants that acquired this glycan were sensitive. Analysis of large sequence and neutralization data sets showed the 332 glycan to be significantly under-represented in transmitted subtype C viruses compared to chronic viruses, with the absence of this glycan corresponding with resistance to PGT128. These findings highlight the dynamic interplay between early antibodies and viral escape in driving the evolution of conserved BCN antibody epitopes.
Features of recently transmitted HIV-1 clade C viruses that impact antibody recognition : implications for active and passive immunization.
(Public Library of Science., 2016) Rademeyer, Cecilia.; Korber, Bette T. M.; Seaman, Michael S.; Giorgi, Elena E.; Thebus, Ruwayhida.; Robles, Alexander.; Sheward, Daniel J.; Wagh, Kshitij.; Garrity, Jetta.; Carey, Brittany R.; Gao, Hongmei.; Greene, Kelli M.; Tang, Haili.; Bandawe, Gama P.; Marais, Jinny C.; Diphoko, Thabo E.; Hraber, Peter.; Tumba, Nancy Lola.; Moore, Penelope L.; Gray, Glenda Elizabeth.; Kublin, James.; McElrath, Margaret Juliana.; Vermeulen, Marion.; Middelkoop, Keren.; Bekker, Linda-Gail.; Hoelscher, Michael.; Maboko, Leonard.; Makhema, Joseph.; Robb, Merlin L.; Abdool Karim, Salim Safurdeen.; Abdool Karim, Quarraisha.; Kim, Jerome H.; Hahn, Beatrice H.; Gao, Feng.; Swanstrom, Ronald.; Morris, Lynn.; Montefiori, David Charles.; Williamson, Carolyn.
Abstract available in PDF file.
The Neutralization Breadth of HIV-1 Develops Incrementally over Four Years and Is Associated with CD4+ T Cell Decline and High Viral Load during Acute Infection.
(American Society for Microbiology., 2011) Gray, Elin Solomonovna.; Madiga, Maphuti C.; Hermanus, Tandile.; Moore, Penelope L.; Wibmer, Constantinos Kurt.; Tumba, Nancy Lola.; Werner, Lise.; Mlisana, Koleka Patience.; Sibeko, Sengeziwe.; Williamson, Carolyn.; Abdool Karim, Salim Safurdeen.; Morris, Lynn.
An understanding of how broadly neutralizing activity develops in HIV-1-infected individuals is needed to guide vaccine design and immunization strategies. Here we used a large panel of 44 HIV-1 envelope variants (subtypes A, B, and C) to evaluate the presence of broadly neutralizing antibodies in serum samples obtained 3 years after seroconversion from 40 women enrolled in the CAPRISA 002 acute infection cohort. Seven of 40 participants had serum antibodies that neutralized more than 40% of viruses tested and were considered to have neutralization breadth. Among the samples with breadth, CAP257 serum neutralized 82% (36/44 variants) of the panel, while CAP256 serum neutralized 77% (33/43 variants) of the panel. Analysis of longitudinal samples showed that breadth developed gradually starting from year 2, with the number of viruses neutralized as well as the antibody titer increasing over time. Interestingly, neutralization breadth peaked at 4 years postinfection, with no increase thereafter. The extent of cross-neutralizing activity correlated with CD4+T cell decline, viral load, and CD4+T cell count at 6 months postinfection but not at later time points, suggesting that early events set the stage for the development of breadth. However, in a multivariate analysis, CD4 decline was the major driver of this association, as viral load was not an independent predictor of breadth. Mapping of the epitopes targeted by cross-neutralizing antibodies revealed that in one individual these antibodies recognized the membrane-proximal external region (MPER), while in two other individuals, cross-neutralizing activity was adsorbed by monomeric gp120 and targeted epitopes that involved the N-linked glycan at position 332 in the C3 region. Serum antibodies from the other four participants targeted quaternary epitopes, at least 2 of which were PG9/16-like and depended on the N160 and/or L165 residue in the V2 region. These data indicate that fewer than 20% of HIV-1 subtype C-infected individuals develop antibodies with cross-neutralizing activity after 3 years of infection and that these antibodies target different regions of the HIV-1 envelope, including as yet uncharacterized epitopes.
Potent and broad HIV-neutralizing antibodies in memory B cells and plasma.
(American Association for the Advancement of Science., 2017) Williams, LaTonya D.; Ofek, Gilad.; Schätzle, Sebastian.; McDaniel, Jonathan R.; Lu, Xiaozhi.; Nicely, Nathan I.; Wu, Liming; Lougheed, Caleb S.; Bradley, Todd.; Louder, Mark K.; McKee, Krisha.; Bailer, Robert T.; O’Dell, Sijy.; Georgiev, Ivelin S.; Seaman, Michael S.; Parks, Robert J.; Marshall, Dawn J.; Anasti, Kara.; Yang, Guang.; Nie, Xiaoyan.; Tumba, Nancy Lola.; Wiehe, Kevin.; Wagh, Kshitij.; Korber, Bette T. M.; Kepler, Thomas B.; Alam, Shabnam Munir.; Morris, Lynn.; Kamanga, Gift.; Cohen, Myron S.; Bonsignori, Mattia.; Xia, Shi-Mao.; Montefiori, David Charles.; Kelsoe, Garnett.; Gao, Feng.; Mascola, John R.; Moody, Michael Anthony.; Saunders, Kevin O.; Liao, Hua-Xin.; Tomaras, Georgia D.; Georgiou, George.; Haynes, Barton F.
Abstract available in pdf.
Potent and Broad Neutralization of HIV-1 Subtype C by Plasma Antibodies Targeting a Quaternary Epitope Including Residues in the V2 Loop.
(American Society for Microbiology., 2010) Moore, Penelope L.; Gray, Elin Solomonovna.; Sheward, Daniel J.; Madiga, Maphuti C.; Ranchobe, Nthabeleng.; Honnen, William J.; Nonyane, Molati.; Tumba, Nancy Lola.; Hermanus, Tandile.; Sibeko, Sengeziwe.; Mlisana, Koleka Patience.; Abdool Karim, Salim Safurdeen.; Williamson, Carolyn.; Pinter, Abraham.; Morris, Lynn.; Lai, Zhong.
The targets of broadly cross-neutralizing (BCN) antibodies are of great interest in the HIV vaccine field. We have identified a subtype C HIV-1-superinfected individual, CAP256, with high-level BCN activity, and characterized the antibody specificity mediating breadth. CAP256 developed potent BCN activity peaking at 3 years postinfection, neutralizing 32 (76%) of 42 heterologous viruses, with titers of antibodies against some viruses exceeding 1:10,000. CAP256 showed a subtype bias, preferentially neutralizing subtype C and A viruses over subtype B viruses. CAP256 BCN serum targeted a quaternary epitope which included the V1V2 region. Further mapping identified residues F159, N160, L165, R166, D167, K169, and K171 (forming the FN/LRD-K-K motif) in the V2 region as crucial to the CAP256 epitope. However, the fine specificity of the BCN response varied over time and, while consistently dependent on R166 and K169, became gradually less dependent on D167 and K171, possibly contributing to the incremental increase in breadth over 4 years. The presence of an intact FN/LRD-K-K motif in heterologous viruses was associated with sensitivity, although the length of the adjacent V1 loop modulated the degree of sensitivity, with a shorter V1 region significantly associated with higher titers. Repair of the FN/LRD-K-K motif in resistant heterologous viruses conferred sensitivity, with titers sometimes exceeding 1:10,000. Comparison of the CAP256 epitope with that of the PG9/PG16 monoclonal antibodies suggested that these epitopes overlapped, adding to the mounting evidence that this may represent a common neutralization target that should be further investigated as a potential vaccine candidate.
Structure and immune recognition of trimeric pre-fusion HIV-1 Env.
(Macmillan Publishers Limited., 2014) Pancera, Marie.; Zhou, Tongqing.; Druz, Aliaksandr.; Georgiev, Ivelin S.; Soto, Cinque.; Gorman, Jason.; Huang, Jinghe.; Acharya, Priyamvada.; Chuang, Gwo-Yu.; Ofek, Gilad.; Stewart-Jones, Guillaume B. E.; Stuckey, Jonathan.; Bailer, Robert T.; Joyce, M. Gordon.; Louder, Mark K.; Tumba, Nancy Lola.; Yang, Yongping.; Zhang, Baoshan.; Cohen, Myron S.; Haynes, Barton F.; Mascola, John R.; Morris, Lynn.; Munro, James B.; Blanchard, Scott C.; Mothes, Walther.; Connors, Mark.; Kwong, Peter D.
The human immunodeficiency virus type 1 (HIV-1) envelope (Env) spike, comprising three gp120 and three gp41 subunits, is a conformational machine that facilitates HIV-1 entry by rearranging from a mature unliganded state, through receptor-bound intermediates, to a post-fusion state. As the sole viral antigen on the HIV-1 virion surface, Env is both the target of neutralizing antibodies and a focus of vaccine efforts. Here we report the structure at 3.5 Å resolution for an HIV-1 Env trimer captured in a mature closed state by antibodies PGT122 and 35O22. This structure reveals the pre-fusion conformation of gp41, indicates rearrangements needed for fusion activation, and defines parameters of immune evasion and immune recognition. Pre-fusion gp41 encircles amino- and carboxy-terminal strands of gp120 with four helices that form a membrane-proximal collar, fastened by insertion of a fusion peptide-proximal methionine into a gp41-tryptophan clasp. Spike rearrangements required for entry involve opening the clasp and expelling the termini. N-linked glycosylation and sequence-variable regions cover the pre-fusion closed spike; we used chronic cohorts to map the prevalence and location of effective HIV-1-neutralizing responses, which were distinguished by their recognition of N-linked glycan and tolerance for epitope-sequence variation.
Viral escape from HIV-1 neutralizing antibodies drives increased plasma neutralization breadth through sequential recognition of multiple epitopes and immunotypes.
(Plos., 2013) Wibmer, Constantinos Kurt.; Bhiman, Jinal N.; Gray, Elin Solomonovna.; Tumba, Nancy Lola.; Abdool Karim, Salim Safurdeen.; Williamson, Carolyn.; Morris, Lynn.; Moore, Penelope L.
Identifying the targets of broadly neutralizing antibodies to HIV-1 and understanding how these antibodies develop remain important goals in the quest to rationally develop an HIV-1 vaccine. We previously identified a participant in the CAPRISA Acute Infection Cohort (CAP257) whose plasma neutralized 84% of heterologous viruses. In this study we showed that breadth in CAP257 was largely due to the sequential, transient ppearance of three distinct broadly neutralizing antibody specificities spanning the first 4.5 years of infection. The first specificity targeted an epitope in the V2 region of gp120 that was also recognized by strain-specific antibodies 7 weeks earlier. Specificity for the autologous virus was determined largely by a rare N167 antigenic variant of V2, with viral escape to the more common D167 immunotype coinciding with the development of the first wave of broadly neutralizing antibodies. Escape from these broadly neutralizing V2 antibodies through deletion of the glycan at N160 was associated with exposure of an epitope in the CD4 binding site that became the target for a second wave of broadly neutralizing antibodies. Neutralization by these CD4 binding site antibodies was almost entirely dependent on the glycan at position N276. Early viral escape mutations in the CD4 binding site drove an increase in wave two neutralization breadth, as this second wave of heterologous neutralization matured to recognize multiple immunotypes within this site. The third wave targeted a quaternary epitope that did not overlap any of the four known sites of vulnerability on the HIV-1 envelope and remains undefined. Altogether this study showed that the human immune system is capable of generating multiple broadly neutralizing antibodies in response to a constantly evolving viral population that exposes new targets as a consequence of escape from earlier neutralizing antibodies.