Peripheral cytokine responses to Trichuris muris reflect those occurring locally at the site of infection

The study of human cellular immune responses to parasite infection under fi eld conditions is very complex. Often, the only practical site from which t o sample the cellular responses is the peripheral blood. Sampling periphera l blood lymphocytes (PBL) relies on the assumption that these peripheral re sponses accurately reflect the immune responses acting locally at the site of infection. This is a particularly important point for the human intestin al helminth Trichuris trichiura, which solely inhabits the cecum and large intestine and so will stimulate a localized immune response. Using the well -defined model of T. trichiura, T. muris in the mouse, we have demonstrated that the dominant cytokine responses of the mesenteric lymph nodes (MLN) c an be detected by sampling PBL, Resistant mice which mount a type 2 cytokin e response in their MLN had PBL producing interleukin-4 (IL-4), IL-5, and I L-9, with negligible levels of gamma interferon (IFN-gamma), Conversely, su sceptible mice which mount a type 1 cytokine response in their MLN had PBL producing IFN-gamma and negligible levels of type 2 cytokines, We have also shown that the PBL are capable of mounting a functional immune response ag ainst T. muris. PBL from immune mice were capable of transferring immunity to T. muris-infected severe combined immunodeficient (C.B-17 scid/scid) mic e. Sampling PBL responses is therefore a viable option for monitoring human intestinal immune responses during T. trichiura infection in the field.