Cell surface glycoproteins of cytotoxic T lymphocytes induced in vivo and in vitro.

CTL-blasts, generated in vitro or obtained from educated spleens in vivo, have previously been shown to display high levels of a unique membrane glycoprotein T145 (ca. 145,000 daltons), inferred to be a common CTL marker and implicated in CTL cytotoxicity. As shown here, however, these suggestions do not hold for all cytotoxic T lymphocytes. We have shown that T145 is not expressed on highly active CTL-induced in vivo by a standard alloimmunization protocol. The finding that several CTL populations are T145 positive, whereas others are T145 negative, may be due to the existence of functional CTL in 2 stages of differentiation or may represent different CTL lineages. In addition, no correlation was found between cytolytic activity and expression of T145. The functional significance of T145 on CTL is discussed.