'Trichostrongylus colubriformis' induces IgE-independent CD13,CD164 and CD203c mediated activation of basophils in anin vitro intestinal epithelial cell co-culture model

Gastrointestinal nematodes pose a major risk to the farming of small ruminants worldwide. Infections are typically controlled by anthelmintics, however as resistance to anthelmintics increases, it is necessary that the mechanism of host responses are understood in order to develop alternative control options. It is hypothesised that basophils are involved in the initiation of an anti-parasite immune response, independent of IgE. In this study, the in vitro activation states of CD203c+ basophil-like KU812 cells were determined in the presence of 'Trichostrongylus colubriformis' parasitised HT29 epithelial cells with or without mucin. Cell surface expression of CD164, CD107a and CD13 antigens on gated CD203+ cells were determined and qRT-PCR was used to examine gene expression changes of IL33 (a Th2 cytokine) and the high affinity IgE receptor (FcεRIα) within the co-culture. When KU812 basophils encountered 'T. colubriformis' and/or mucin in a parasitised epithelium, the basophils increased cell surface expression of CD13 and CD164 antigens, independent of IgE. 'T. colubriformis' also increased the number of CD203c+ KU812 cells that expressed CD13 and CD164 antigens. These data support the in vivo observations of 'T. colubriformis' primary infections in guinea pigs and sheep.