CXCL13 is a plasma biomarker of germinal center activity

Proc Natl Acad Sci U S A. 2016 Mar 8;113(10):2702-7. doi: 10.1073/pnas.1520112113. Epub 2016 Feb 23.

Abstract

Significantly higher levels of plasma CXCL13 [chemokine (C-X-C motif) ligand 13] were associated with the generation of broadly neutralizing antibodies (bnAbs) against HIV in a large longitudinal cohort of HIV-infected individuals. Germinal centers (GCs) perform the remarkable task of optimizing B-cell Ab responses. GCs are required for almost all B-cell receptor affinity maturation and will be a critical parameter to monitor if HIV bnAbs are to be induced by vaccination. However, lymphoid tissue is rarely available from immunized humans, making the monitoring of GC activity by direct assessment of GC B cells and germinal center CD4(+) T follicular helper (GC Tfh) cells problematic. The CXCL13-CXCR5 [chemokine (C-X-C motif) receptor 5] chemokine axis plays a central role in organizing both B-cell follicles and GCs. Because GC Tfh cells can produce CXCL13, we explored the potential use of CXCL13 as a blood biomarker to indicate GC activity. In a series of studies, we found that plasma CXCL13 levels correlated with GC activity in draining lymph nodes of immunized mice, immunized macaques, and HIV-infected humans. Furthermore, plasma CXCL13 levels in immunized humans correlated with the magnitude of Ab responses and the frequency of ICOS(+) (inducible T-cell costimulator) Tfh-like cells in blood. Together, these findings support the potential use of CXCL13 as a plasma biomarker of GC activity in human vaccine trials and other clinical settings.

Keywords: CXCL13; HIV; Tfh; antibodies; vaccines.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biomarkers / blood*
  • Chemokine CXCL13 / blood*
  • Chemokine CXCL13 / immunology*
  • Cohort Studies
  • Enzyme-Linked Immunosorbent Assay
  • Flow Cytometry
  • Germinal Center / immunology*
  • HIV Infections / blood
  • HIV Infections / immunology
  • Humans
  • Lymph Nodes / immunology
  • Macaca
  • Mice, Inbred C57BL
  • Vaccination

Substances

  • Biomarkers
  • Chemokine CXCL13