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

McCarthy, Mary K.; Reynoso, Glennys V.; Winkler, Emma S.; Mack, Matthias; Diamond, Michael S.; Hickman, Heather D.; Morrison, Thomas E.

https://doi.org/10.1371/journal.ppat.1008292.g002 the accumulation of monocytes and neutrophils in the dLN following pathogenic CHIKV infection. As shown in Fig 5A, the total number of dLN cells following pathogenic CHIKV infection was reduced in Ifnar1 -/compared with wild-type (WT) mice; type I IFN signaling normally inhibits lymphocyte egress [30] , but this does not occur in mice lacking the type I IFN receptor and likely contributes to the reduced cell numbers. The percentage of neutrophils was increased in the dLN of Ifnar1 -/mice compared with WT mice after pathogenic CHIKV infection (Fig 5B and 5C) , which resulted in a similar total number of neutrophils in the dLN of WT and Ifnar1 -/mice (Fig 5D) despite the overall decrease in total number of dLN cells. The frequencies of Ly6C hi monocytes were similar in the dLN of CHIKV-infected WT and Ifnar1 -/mice (Fig 5E) although the total number of monocytes in the dLN was reduced in Ifnar1 -/mice.