Figure 4.

Oral administration of antigen does not induce proliferation of antigen-specific T cells in transplanted PP and MLN that are connected to the host circulation but not to afferent lymphatics of the host intestine. Intestinal segments together with completely intact donor MLN were transplanted into syngenic wild-type recipients. Grafts were connected to the host blood circulation and both graft ends were exteriorized as stomata. Subsequently, recipient mice were adoptively transferred with 10⁷ CFSE-labeled OTII cells. 2 d after feeding of 100 mg ovalbumin (oral), proliferation of ovalbumin-specific TCR-transgenic T cells occurred only in endogenous but not in transplanted organs, whereas systemic administration of antigen by intravenous injection (i.v.) resulted in comparable reactions in grafted and host gut-associated lymphoid tissue. Note that naive transgenic cells were present in the grafted MLN/PP, indicating a successful coupling to the recipients' lymphocyte recirculation. Dot plots are gated on Vα2/Vβ5-positive lymphocytes.