CD200 Receptor 2 (CD200R2)

CD200 delivers immunoregulatory signals following engagement of its receptor, CD200R. A family of CD200Rs (CD200R1-4) has been described. Spleen expresses cell surface CD200R1, while bone marrow shows predominantly expression of cell surface CD200R2/R3. Dendritic cell precursors (DCp) cultured with anti-CD200R2/3 develop the capacity to induce CD4(+)CD25(+) regulatory T cells (Treg) from peripheral lymphocytes. Foxp3(+) CD4(+)CD25(+) Treg were derived from 60-hr thymocyte and splenocyte T cell cultures using both DC populations. Cloned C3H Treg (Foxp3(+)) suppressed both C3H anti-BL/6 reactivity in a fresh MLC and rejection of BL/6 skin allografts in C3H recipients; the converse was true for BL/6 Treg. CD200 triggering of bone-marrow DCs in the absence of CD200R1 engagement induces CD4(+)CD25(+) Treg, and these cloned antigen-specific Treg may have clinical utility.