Encephalitogenic, myelin basic protein-specific T cells from naive rat thymus: preferential use of the T cell receptor gene Vβ8.2 and expression of the CD4− CD8− phenotype

✍ Scribed by Joseli Lannes-Vieira; Bernard Goudable; Klaus Drexler; Jochen Gehrmann; Nora Torres-Nagel; Thomas Hünig; Hartmut Wekerle

• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 1001 KB
• Volume: 25
• Category: Article
• ISSN: 0014-2980
• DOI: 10.1002/eji.1830250245

✦ Synopsis

Abstract

Using a primary limiting dilution approach to generate T cell lines, we compared myelin basic protein (MBP)‐specific T cell clones from naive unprimed Lewis rat thymuses with the corresponding T cell repertoire of primed rats. We found that in the naive thymus repertoire MBP‐specific, encephalitogenic T cell clones preferentially use T cell receptor Vβ8.2 genes, along with CDR3 sequences typical for the primed Lewis anti‐MBP response. In contrast to T cells from primed immune organs, which all display the CD4^+^ CD8^−^ phenotype, the majority of naive thymus‐derived T cell clones expressed reduced levels of the CD4 co‐receptor. Some clones were completely CD4^−^CD8^−^, while others included CD4^−^ CD8^−^ subpopulations along with CD4^+^CD8^−^ T cells. In the one mixed population examined in detail, the CD4^−^CD8^−^ and CD4^+^CD8^−^ T cell subpopulations used a T cell receptor with identical β chain sequence. The data suggest that in the Lewis rat the biased T cell receptor gene usage by encephalitogenic T cells is a property of the natural thymic T cell repertoire, possibly as a consequence of positive selection. The unusually low expression of CD4 in the major histocompatibility complex class II‐restricted autoreactive T cells could be related to their escape from negative selection within the thymus.