CD4 and colitis: As we have employed a CD4+ T cell-dependent colitis model and indeed observed considerably reduced CD4+ T cell numbers and correspondingly also mRNA levels for IFNγ and IL-17 in the colonic LP of transferred Trem1−/− x Rag2−/− mice, the question arises whether deficiency in TREM-1 may directly impact the priming of adaptive immune responses.