Melis N Anahtar

Publications (2)19.58 Total impact

• Article: Rapid, efficient functional characterization and recovery of HIV-specific human CD8+ T cells using microengraving.

  Navin Varadarajan, Douglas S Kwon, Kenneth M Law, Adebola O Ogunniyi, Melis N Anahtar, James M Richter, Bruce D Walker, J Christopher Love
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  ABSTRACT: The nature of certain clinical samples (tissue biopsies, fluids) or the subjects themselves (pediatric subjects, neonates) often constrain the number of cells available to evaluate the breadth of functional T-cell responses to infections or therapeutic interventions. The methods most commonly used to assess this functional diversity ex vivo and to recover specific cells to expand in vitro usually require more than 10(6) cells. Here we present a process to identify antigen-specific responses efficiently ex vivo from 10(4)-10(5) single cells from blood or mucosal tissues using dense arrays of subnanoliter wells. The approach combines on-chip imaging cytometry with a technique for capturing secreted proteins--called "microengraving"--to enumerate antigen-specific responses by single T cells in a manner comparable to conventional assays such as ELISpot and intracellular cytokine staining. Unlike those assays, however, the individual cells identified can be recovered readily by micromanipulation for further characterization in vitro. Applying this method to assess HIV-specific T-cell responses demonstrates that it is possible to establish clonal CD8(+) T-cell lines that represent the most abundant specificities present in circulation using 100- to 1,000-fold fewer cells than traditional approaches require and without extensive genotypic analysis a priori. This rapid (<24 h), efficient, and inexpensive process should improve the comparative study of human T-cell immunology across ages and anatomic compartments.
  Proceedings of the National Academy of Sciences 03/2012; 109(10):3885-90. · 9.68 Impact Factor
• Article: Epithelial adhesion molecules can inhibit HIV-1-specific CD8⁺ T-cell functions.

  Hendrik Streeck, Douglas S Kwon, Augustine Pyo, Michael Flanders, Mathieu F Chevalier, Kenneth Law, Boris Jülg, Kasper Trocha, Jonathan S Jolin, Melis N Anahtar, [......], Ildiko Toth, Zabrina Brumme, J Judy Chang, Tyler Caron, Scott J Rodig, Danny A Milner, Alicja Piechoka-Trocha, Daniel E Kaufmann, Bruce D Walker, Marcus Altfeld
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  ABSTRACT: Under persistent antigenic stimulation, virus-specific CD8⁺ T cells become increasingly dysfunctional and up-regulate several inhibitory molecules such as killer lectin-like receptor G1 (KLRG1). Here, we demonstrate that HIV-1 antigen-specific T cells from subjects with chronic-progressive HIV-1 infection have significantly elevated KLRG1 expression (P < .001); show abnormal distribution of E-cadherin, the natural ligand of KLRG1, in the intestinal mucosa; and have elevated levels of systemic soluble E-cadherin (sE-cadherin) that significantly correlate with HIV-1 viral load (R = 0.7, P = .004). We furthermore demonstrate that in the presence of sE-cadherin, KLRG1(hi) HIV-1-specific CD8⁺ T cells are impaired in their ability to respond by cytokine secretion on antigenic stimulation (P = .002) and to inhibit viral replication (P = .03) in vitro. Thus, these data suggest a critical mechanism by which the disruption of the intestinal epithelium associated with HIV-1 leads to increased systemic levels of sE-cadherin, which inhibits the effector functions of KLRG1(hi)-expressing HIV-1-specific CD8⁺ T cells systemically.
  Blood 03/2011; 117(19):5112-22. · 9.90 Impact Factor