To determine the function of A20 in gingival keratinocytes, our next set of experiments employed loss and gain of function assays in which A20 knockdown (siRNA, or the CRISPR/Cas9 genome editing and lentivirus transduction) and overexpressing (lentivirus transduction) systems were constructed followed by oral bacterial infections. This evidence concerns the gene TNFAIP3 and bacterial infectious disease.