A sub-population of circulating porcine γδ T cells can act as professional antigen presenting cells

A sub-population of circulating porcine 76 T cells express cell surface antigens associated with antigen presenting cells (APCs), and are able to take up soluble antigen,,cry effectively. Functional antigen presentation by 76 T cells to memory helper T cells was studied by inbred pig lymphocytes immunised with ovalbumin (OVA). After removing all conventional APCs from the peripheral blood of immunised pigs, the remaining lymphocytes still proliferated when stimulated with OVA. When ydelta T cells were further depleted, OVA specific proliferation was abolished, but reconstitution with 6 T cells restored proliferation. The proliferation was blocked by monoclonal antibodies (mAb) against MHC class II or CD4, and by pre-treatment of gammadelta T cells with chloroquine. These results indicate that a sub-population of circulating porcine gammadelta T cells act as APCs and present antigen via MHC class II. (C) 2002 Elsevier Science B.V. All rights reserved.