• Progressive contraction of the latent HIV reservoir around a core of less-differentiated CD4⁺ memory T Cells.

      Jaafoura, S; de Goër de Herve, M G; Hernandez-Vargas, Esteban Abelardo; Hendel-Chavez, H; Abdoh, M; Mateo, M C; Krzysiek, R; Merad, M; Seng, R; Tardieu, M; et al. (2014)
      In patients who are receiving prolonged antiretroviral treatment (ART), HIV can persist within a small pool of long-lived resting memory CD4(+) T cells infected with integrated latent virus. This latent reservoir involves distinct memory subsets. Here we provide results that suggest a progressive reduction of the size of the blood latent reservoir around a core of less-differentiated memory subsets (central memory and stem cell-like memory (TSCM) CD4(+) T cells). This process appears to be driven by the differences in initial sizes and decay rates between latently infected memory subsets. Our results also suggest an extreme stability of the TSCM sub-reservoir, the size of which is directly related to cumulative plasma virus exposure before the onset of ART, stressing the importance of early initiation of effective ART. The presence of these intrinsic dynamics within the latent reservoir may have implications for the design of optimal HIV therapeutic purging strategies.
    • Visualizing antibody affinity maturation in germinal centers.

      Tas, Jeroen M J; Mesin, Luka; Pasqual, Giulia; Targ, Sasha; Jacobsen, Johanne T; Mano, Yasuko M; Chen, Casie S; Weill, Jean-Claude; Reynaud, Claude-Agnès; Browne, Edward P; et al. (2016-03-04)
      Antibodies somatically mutate to attain high affinity in germinal centers (GCs). There, competition between B cell clones and among somatic mutants of each clone drives an increase in average affinity across the population. The extent to which higher-affinity cells eliminating competitors restricts clonal diversity is unknown. By combining multiphoton microscopy and sequencing, we show that tens to hundreds of distinct B cell clones seed each GC and that GCs lose clonal diversity at widely disparate rates. Furthermore, efficient affinity maturation can occur in the absence of homogenizing selection, ensuring that many clones can mature in parallel within the same GC. Our findings have implications for development of vaccines in which antibodies with nonimmunodominant specificities must be elicited, as is the case for HIV-1 and influenza.