MyD88-dependent influx of monocytes and neutrophils impairs lymph node B cell responses to chikungunya virus infection via Irf5, Nos2 and Nox2

PLoS Pathog. 2020 Jan 30;16(1):e1008292. doi: 10.1371/journal.ppat.1008292. eCollection 2020 Jan.

Abstract

Humoral immune responses initiate in the lymph node draining the site of viral infection (dLN). Some viruses subvert LN B cell activation; however, our knowledge of viral hindrance of B cell responses of important human pathogens is lacking. Here, we define mechanisms whereby chikungunya virus (CHIKV), a mosquito-transmitted RNA virus that causes outbreaks of acute and chronic arthritis in humans, hinders dLN antiviral B cell responses. Infection of WT mice with pathogenic, but not acutely cleared CHIKV, induced MyD88-dependent recruitment of monocytes and neutrophils to the dLN. Blocking this influx improved lymphocyte accumulation, dLN organization, and CHIKV-specific B cell responses. Both inducible nitric oxide synthase (iNOS) and the phagocyte NADPH oxidase (Nox2) contributed to impaired dLN organization and function. Infiltrating monocytes expressed iNOS through a local IRF5- and IFNAR1-dependent pathway that was partially TLR7-dependent. Together, our data suggest that pathogenic CHIKV triggers the influx and activation of monocytes and neutrophils in the dLN that impairs virus-specific B cell responses.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural

MeSH terms

  • Animals
  • B-Lymphocytes / immunology*
  • Chikungunya Fever / immunology*
  • Chikungunya Fever / virology
  • Chikungunya virus / physiology
  • Humans
  • Interferon Regulatory Factors / genetics
  • Interferon Regulatory Factors / immunology*
  • Lymph Nodes / immunology
  • Lymph Nodes / virology
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Monocytes / immunology*
  • Myeloid Differentiation Factor 88 / genetics
  • Myeloid Differentiation Factor 88 / immunology*
  • NADPH Oxidase 2 / genetics
  • NADPH Oxidase 2 / immunology*
  • Neutrophils / immunology*
  • Nitric Oxide Synthase Type II / genetics
  • Nitric Oxide Synthase Type II / immunology*

Substances

  • Interferon Regulatory Factors
  • Irf5 protein, mouse
  • Myd88 protein, mouse
  • Myeloid Differentiation Factor 88
  • Nitric Oxide Synthase Type II
  • Nos2 protein, mouse
  • Cybb protein, mouse
  • NADPH Oxidase 2