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

MK McCarthy, GV Reynoso, ES Winkler, M Mack… - PLoS …, 2020 - journals.plos.org
PLoS pathogens, 2020journals.plos.org
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 …
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.
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