Expression of the Thy-1 gene in human T lymphoid cell lines.

We have previously shown that three human T cell lines (MOLT-3, HUT-78 and HUT-102) were able to react with anti-human brain Thy-1 sera by cell surface immunofluorescence. However, the possibility that the antisera might cross-react with molecules other than Thy-1 could not be entirely excluded. In this report, mRNA prepared from these three T cell lines as well as from a murine T cell line (EL4) and a human B cell line (Raji) was subjected to Northern blot analysis and probed with a murine Thy-1.2 gene fragment. The result confirms our cell surface immunofluorescence data and indicates that HUT-78 and HUT-102 cells have approximately 20-fold more of the Thy-1 mRNA than MOLT-3 cells do. The Thy-1 mRNA was not detectable in the human B cell line Raji. This work is the first demonstration that the Thy-1 gene is expressed in human T cell lines. The finding is helpful in clarifying the current confusion regarding the expression of Thy-1 in human lymphoid cells and it also provides a possible model system for exploring the function of Thy-1 in cultured human T lymphocytes.