Human T‐cell leukemia virus type‐I‐infected T‐cell lines scarcely produce p56lck, whether or not they express lck MRNA

Abstract
We have previously reported that lck mRNA (a lymphocyte‐specific protein tyrosine kinase gene) is absent in human T‐cell leukemia virus type I (HTLV‐I)‐infected interleukin‐2(IL‐2)‐independent T‐cell lines, while HTLV‐I‐negative T‐cell lines and HTLV‐I‐positive IL‐2‐dependent ones express a large amount of lck mRNA. To further investigate the levels of lck expression, we prepared rabbit anti‐Lck antiserum directed against the synthetic oligopeptide of 32 amino acids corresponding to the carboxy terminus of this gene product, p56lck. Using this antiserum, we show that HTLV‐I‐positive T‐cell lines, whether they are IL‐2‐dependent or not, scarcely express p56lck. In other words, IL‐2‐dependent HTLV‐I‐positive T‐cell lines seldom produce p56lck In spite of high expression of lck mRNA. Absence of p56lck is suspected of playing an important role in malignant transformation of HTLV‐I‐infected T‐cells.