Abstract
N-methyl-N-nitrosourea induces murine CD4-8+ T-lymphomas that express high levels
of J11d and low levels of CD5 antigens, a phenotype characteristic of immature CD4-8+
thymocytes. This assignment is supported by the fact that CD4-8+ lymphoma cell lines
acquire CD4 expression after intrathymic (i.t.) transfer, a finding consistent with the
established precursor potential of the normal immature CD4-8+ subset. CD4+8+ lymphomas recovered after i.t. transfer maintain a CD4+8+ phenotype in long-term culture. Northern blot analyses reveal that CD4 expression is regulated at the
transcriptional level in immature CD4-8+ and CD4+8+ cell lines. CD4-8+ lymphomas
express low levels of functional CD3/TCR complexes that mediate intracellular Ca2+
mobilization in response to CD3 or