Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0024312 (lymphopenia)
 4,859 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We examined the infiltration of acutely rejecting renal allografts (DA-->LEW) by ED1+ and ED2+ macrophages and T lymphocytes at intervals of 24 h after transplantation. Donor and recipient macrophages were differentiated by MHC class II antigen expression in double-staining experiments with ED1. Proliferation was assayed after pulse-labelling with BrdU. We subdivided allograft infiltration into three consecutive phases: 1) During phase I on days 1 to 2 after allogeneic kidney transplantation, perivascular infiltrates developed that contained numerous donor and recipient macrophages. Allograft rejection could already be diagnosed 24 h after transplantation by perivascular infiltration of T lymphocytes, whereas T cells were rarely found in isografts. 2) Phase II of allograft rejection from day 3 to 4 was characterized by massive propagation of the infiltrate. About equal numbers of interstitial donor and recipient macrophages were counted. Both macrophages and T lymphocytes proliferated in situ and macrophages outnumbered T cells until complete rejection. 3) During phase III the allograft was destroyed. Large intravascular monocytes surprisingly expressed the ED2 antigen. In the interstitium of viable graft regions, the population of recipient macrophages grew, whereas the population of donor macrophages and of T lymphocytes decreased.
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PMID:Dynamics of monocytes/macrophages and T lymphocytes in acutely rejecting rat renal allografts. 939 49

Biobreeding-diabetes prone (BB-DP) rats spontaneously develop organ-specific autoimmunity and are severely lymphopenic and particularly deficient in ART2(+) regulatory T cells. A special breed, the so-called BB-diabetic-resistant (DR) rats, are not lymphopenic and do not develop organ-specific autoimmunity. The genetic difference between both strains is the lymphopenia (lyp) gene. Intrathymic tolerance mechanisms are important to prevent autoimmunity, and next to thymus epithelial cells, thymus APC play a prominent part in this tolerance. We here embarked on a study to detect defects in thymus APC of the BB-DP rat and isolated thymus APC using a protocol based on the low-density and nonadherent character of the cells. We used BB-DP, BB-DR, wild-type F344, and F344 rats congenic for the lyp gene-containing region. The isolated thymus, nonadherent, low-density cells appeared to be predominantly ED2(+) branched cortical macrophages and not OX62(+) thymus medullary and cortico-medullary dendritic cells. Functionally, these ED2(+) macrophages were excellent stimulators of T cell proliferation, but it is more important that they rescued double-positive thymocytes from apoptosis. The isolated thymus ED2(+) macrophages of the BB-DP and the F344.lyp/lyp rat exhibited a reduced T cell stimulatory capacity as compared with such cells of nonlymphopenic rats. They had a strongly diminished capability of rescuing thymocytes from apoptosis (also of ART2(+) T cells) and showed a reduced Ian5 expression (as lyp/lyp thymocytes do). Our experiments strongly suggest that branched cortical macrophages play a role in positive selection of T cells in the thymus and point to defects in these cells in BB-DP rats.
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PMID:Low-density cells isolated from the rat thymus resemble branched cortical macrophages and have a reduced capability of rescuing double-positive thymocytes from apoptosis in the BB-DP rat. 1759 4