Characterization of the human homolog of the rat MRC OX-2 membrane glycoprotein

Abstract

The MRC OX-2 antigen is a membrane glycoprotein present on rat thymocytes, neurons, follicular dendritic cells, endothelium, and some smooth muscle. The sequence of 248 amino acids has similarities to Ig domains organized with one V-like domain, one C-like domain, and transmembrane and cytoplasmic regions. Thus it resembles a T-cell receptor chain but shows no sequence divergence. We report the characterization of the human gene for this molecule. Its exon organization is similar to that found for immunoglobulins although the region with similarities to Ig J regions is found within the same exon as the V-like domain. Human MRC OX-2 is expressed at the mRNA level in brain and B-cell lines but not detected in liver or T-cell lines. It does not obviously correspond to any previously defined leukocyte antigen. The sequence homology for the human and rat MRC OX-2 molecules is higher for the Ig-related region (75%) than for many other Ig-related molecules and very high in the transmembrane region (96%), implying a functional role other than simply its anchoring into the membrane.

Utility of CD200 immunostaining in the diagnosis of primary mediastinal large B cell lymphoma: comparison with MAL, CD23, and other markers

“…CD200 or OX-2 antigen is an immunoglobulin superfamily membrane glycoprotein 1 widely expressed in multiple cell types, including B cells, a subset of T cells, and a number of non-hematopoietic cells. 2 It interacts with CD200R, a receptor expressed primarily on myeloid/monocyte lineage cells, and has a suppressive effect on T cell mediated immune response.…”

Role of Superficial CD200 Marker in Differential Diagnosis of Malignant B-Cell Lymphoproliferative Diseases

“…В заключение следует отметить, что отсутствие экспрессии CD200 на опухолевых В-лимфоцитах исключает диагноз ХЛЛ и типичного ВКЛ, что со-гласуется со всеми изученными нами данными литературы [14][15][16][17][18][19][20][21]. Следовательно, при отсутствии или сниженной экспрессии СD200 следует направить диагностический поиск в сторону ЛМЗ и ЛЗМ.…”

“…CD200 связывается с CD200-рецептором-1, располо-женным на моноцитах, гранулоцитах, субпопуляции Т-лимфоцитов, и вызывает иммуносупрессивный ответ, в частности в противоопухолевом иммунитете. В экспериментах на мышах продемонстрировано, что связывание СD200 cо своим рецептором in vitro способствует дифференцировке Т-лимфоцитов в регуляторные клетки [16][17][18]. Показано также про-гностическое значение экспрессии CD200 при ряде неоплазий гемопоэтической ткани [19,20].…”

Repeated Antigen Challenge Modulates Expression of Follicular Dendritic Cell (FDC) Related Molecule in Draining Lymph Nodes.

“…MRC OX-2 antigen is a membrane glycoprotein of 60,000 MW found in the thymus, B cells, FDCs, neurons, vascular endothelial cells, trophoblasts, smooth muscle cells and in activated, but not resting T cells [15]. This antibody is also considered as a useful marker for FDC.…”