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.

To evaluate which specific Gr-1 + cell type, monocytes or neutrophils, was responsible for the defect in lymphocyte accumulation in the dLN following pathogenic CHIKV infection, we treated mice with an anti-Ly6G mAb to deplete neutrophils alone or an anti-CCR2 mAb [28] to deplete Ly6C hi monocytes alone. In each case, either neutrophils (Fig 3A and 3B ) or monocytes (Fig 3G and 3H ) were specifically depleted from the circulation and the dLN. As we did not observe restoration of dLN total cell numbers at 5 dpi in mice depleted of either neutrophils (Fig 3A-3F ) or Ly6C hi monocytes (Fig 3G-3L) , the influx of either cell type likely can prevent lymphocyte accumulation in the dLN.