RAC1 and mastitis: Presumably, this inflammatory response providedan immune defense able to suppress signs of subclinical mastitis.Among the up-regulated proteins in HS cows were RAC1, CAV1, and ARPC3,all involved in G-protein-coupled signaling activating phagocytosis44,45 or Ras/Raf/Mitogen-activated protein kinase/extracellular-signal-regulatedkinase (RAS-ERK) signaling of T-cell-mediated endocytosis,46 mediating the elimination of potential pathogensin MG tissue.