CD8 alphabeta+ TCR alphabeta(intermediate) lymphocytes expressing skewed TCRVbeta repertoire in the liver of aged athymic nu/nu mice.

Principally, TCRalphabeta cells differentiate and mature in the thymus. However, evidence has accumulated to suggest that some TCRalphabeta cells develop extrathymically. Such cells have been identified in athymic nu/nu mice that are devoid of a functional thymus. They appear relatively late in ontogeny and randomly increase in number as a function of age. Recently, the liver has been suggested as a candidate site for thymus-independent development of T cells. Here we show that CD8alphabeta+ T cells that express TCRalphabeta at intermediate intensity (TCRalpha(beta)int) are preferentially localized in the liver of nu/nu mice. This population encompassed cells expressing lectin cell adhesion molecule-1 and/or IL-2Rbeta and cells lacking either of these surface molecules. The CD8alphabeta+ TCRalpha(beta)int liver lymphocytes in nu/nu mice also differed in their LFA-1 expression marginally, whereas in C57BL/6 mice all CD8alphabeta+ TCRalpha(beta)int liver lymphocytes expressed LFA-1 at low intensity. Although the TCRVbeta repertoire markedly differed among individual animals, the CD8alphabeta+ TCRalpha(beta)int liver lymphocytes in nu/nu mice preferentially used TCRVbeta5 and/or TCRVbeta8. These findings show that CD8alphabeta+ TCRalpha(beta)int cells develop in the liver of nu/nu mice and that they arise randomly.