Diabetes-prone BB rats express the RT6 alloantigen on intestinal intraepithelial lymphocytes.
The RT6 alloantigen of the rat is expressed on most peripheral T cells but not on thymocytes and thus represents a marker for postthymic T lymphocyte maturation in this species. Diabetes-prone (DP) BB rats exhibit a genetically determined T cell lymphopenia associated with a deficiency of RT6+ T cells. In this study we have analyzed the expression of RT6 on lymph node (LN) cells and intestinal intraepithelial lymphocytes (IEL) in two DP BB strains (BB/OK and BB/Mol) and two control strains (non-lymphopenic BB/PhiK and LEW) by flow cytometry. In the DP BB rats the number of LN T cells was substantially reduced (less than 25% TcR2+ cells) and completely lacked RT6 expression. The IEL population was also reduced in number and in marked contrast to normal rats consisted predominantly of CD4+ cells. The majority of IEL, however clearly expressed RT6. Treatment with a phosphatidylinositol (PI)-specific phospholipase C markedly reduced the RT6 density showing that PI-mediated anchoring of RT6 in the cell membrane also applies to IEL of DP BB rats. The results demonstrate that the DP BB strains possess a functional RT6 gene and are also able to generate the PI anchor. The defect in RT6 expression is thus unlikely to be the primary cause of the T cell lymphopenia.
Fangmann
J
J
Klinik für Abdominal- and Transplantationschirurgie, Medizinische Hochschule Hannover, FRG.
Schwinzer
R
R
Hedrich
H J
HJ
Klöting
I
I
Wonigeit
K
K
D000818:Animals; D015703:Antigens, CD / Q000096:biosynthesis; D015704:CD4 Antigens / Q000096:biosynthesis; D018956:CD5 Antigens; D002478:Cells, Cultured; D004848:Epithelium / Q000276:immunology; D005434:Flow Cytometry; D007136:Immunoglobulins / Q000096:biosynthesis; D016130:Immunophenotyping; D007422:Intestines / Q000276:immunology*; D007519:Isoantigens / Q000096:biosynthesis*; D008198:Lymph Nodes / Q000276:immunology; D008231:Lymphopenia; D051381:Rats; D011913:Rats, Inbred BB / Q000276:immunology*; D011917:Rats, Inbred Lew; D011948:Receptors, Antigen, T-Cell / Q000096:biosynthesis; D013601:T-Lymphocytes / Q000276:immunology*
D015703:Antigens, CD; D015704:CD4 Antigens; D018956:CD5 Antigens; D007136:Immunoglobulins; D007519:Isoantigens; D011948:Receptors, Antigen, T-Cell