FCRL5 Delineates Functionally Impaired Memory B Cells Associated with Plasmodium falciparum Exposure

PLoS Pathog. 2015 May 19;11(5):e1004894. doi: 10.1371/journal.ppat.1004894. eCollection 2015 May.

Abstract

Exposure to Plasmodium falciparum is associated with circulating "atypical" memory B cells (atMBCs), which appear similar to dysfunctional B cells found in HIV-infected individuals. Functional analysis of atMBCs has been limited, with one report suggesting these cells are not dysfunctional but produce protective antibodies. To better understand the function of malaria-associated atMBCs, we performed global transcriptome analysis of these cells, obtained from individuals living in an area of high malaria endemicity in Uganda. Comparison of gene expression data suggested down-modulation of B cell receptor signaling and apoptosis in atMBCs compared to classical MBCs. Additionally, in contrast to previous reports, we found upregulation of Fc receptor-like 5 (FCRL5), but not FCRL4, on atMBCs. Atypical MBCs were poor spontaneous producers of antibody ex vivo, and higher surface expression of FCRL5 defined a distinct subset of atMBCs compromised in its ability to produce antibody upon stimulation. Moreover, higher levels of P. falciparum exposure were associated with increased frequencies of FCRL5+ atMBCs. Together, our findings suggest that FCLR5+ identifies a functionally distinct, and perhaps dysfunctional, subset of MBCs in individuals exposed to P. falciparum.

Publication types

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

MeSH terms

  • Adult
  • Animals
  • Antigens, Protozoan / metabolism
  • Asymptomatic Diseases / epidemiology
  • B-Lymphocytes / immunology
  • B-Lymphocytes / metabolism*
  • Caregivers
  • Cell Line
  • Cells, Cultured
  • Child
  • Cohort Studies
  • Endemic Diseases*
  • Gene Expression Profiling
  • Gene Expression Regulation
  • Humans
  • Immunologic Memory*
  • Malaria, Falciparum / epidemiology
  • Malaria, Falciparum / immunology*
  • Malaria, Falciparum / metabolism
  • Malaria, Falciparum / parasitology
  • Mice
  • Plasmodium falciparum / immunology*
  • Receptors, Fc / agonists*
  • Receptors, Fc / genetics
  • Receptors, Fc / metabolism
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / metabolism
  • Uganda / epidemiology

Substances

  • Antigens, Protozoan
  • FCRL4 protein, human
  • FCRL5 protein, human
  • Receptors, Fc
  • Recombinant Proteins

Associated data

  • GEO/GSE64493