T lymphocytes from tonsil and peripheral blood show different cytolytic and helper activities.

T lymphocytes from tonsil (To) and peripheral blood (PB) of 4 tonsillectomized children were subjected to clonal expansion with PHA in order to analyze at single cell level their cytolytic activity and their ability to produce interleukins such as IL-2, IFN-gamma and IL-4. Analyzing all T-cell clones (CD4+ and CD8+) obtained from To in comparison with those from PB, a reduced proportion of cells with lectin-dependent cytolytic activity (LDCC) (25% vs. 42%, p less than 0.01) and natural killer (NK) activity (18% vs. 31%, p less than 0.02) was found. These differences were proportionally related to the lower number of CD8+ T-cells in To than in PB. The proportion of CD4+ clones able to produce IL-2 and/or IL-4 were higher in To (75% and 61%) than in PB (52% and 25%, p less than 0.001 and p less than 0.001, respectively). In contrast, the proportion of CD4+ clones able to produce IFN-gamma was similar (53% and 58%) in both series of clones. According to the patterns of lymphokine synthesis, tonsillar T-cells differed from PB T-cells as follows: 1) the number of Th1-like CD4+ clones producing IL-2 and/or IFN-gamma (but not IL-4) were 23% vs. 44% in PB (p less than 0.001); 2) there was no difference between To and PB in the proportion of CD4+ clones producing IL-4 alone (Th2 clones: 9% vs. 8%); 3) CD4+ clones synthesizing IL-2, IL-4 and IFN-gamma at the same time were more frequent in To than in PB (Th3 clones: 53% vs. 17%, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of a novel cell line from pleomorphic adenoma of the parotid gland with myoepithelial phenotype and producing interleukin-6 as an autocrine growth factor.

A cell line was obtained from a primary culture of a pleomorphic adenoma of the parotid gland in a 24-year-old woman. The cells of the line (PA 16/23) grew spontaneously in minimal culture conditions and showed stable morphologic characteristics over 30 passages. PA 16/23 cells had immunophenotypic and ultrastructural features similar to those of transformed myoepithelial cells, which are regarded as the precursors of pleomorphic adenomas. Furthermore, these cells have been demonstrated immunocytochemically to contain interleukin-6 (IL-6) on light and electron microscopic examination. IL-6 also has been found by enzyme-linked immunosorbent assay in the culture supernatant and has been proven to be capable of stimulating growth of the PA 16/23 cells.

Spontaneous in vitro differentiation of a myoepithelial cell line (PA 16/23) from a pleomorphic adenoma of the parotid gland is associated with reduced production of the autocrine growth factor interleukin 6.

A myoepithelial cell line (PA 16/23) was derived from a pleomorphic adenoma of the parotid gland. PA 16/23 cells have light microscopic, immunophenotypical and ultrastructural features of immature myoepithelial cells, i.e. they are of fusiform or stellate shape and show keratin and actin cytofilaments located mainly in the perinuclear cytoplasm, desmosomes and tracts of basal lamina. The PA 16/23 cells grew actively and expressed mRNA for and produced interleukin 6 (IL-6) which was released into the culture medium. This cytokine, in turn, acted as an autocrine growth factor on the cells. PA 16/23 cells also expressed high-affinity IL-6 receptors. In these cells, both IL-6 production and proliferation could be modulated by exogenous stimulants, such as IL-6 itself, IL-1, IL-4, tumour necrosis factor alpha, interferon gamma and lipopolysaccharide. From the 40th culture passage onwards, the PA 16/23 cells ceased to grow, either spontaneously or in response to exogenous stimulants. Moreover, they strongly reduced IL-6 production, and underwent morphological differentiation into more mature myoepithelial cells, with an increased amount and a different arrangement of the keratin and actin cytofilaments, which formed thick bundles in the peripheral cytoplasm. These findings suggest a role for IL-6 in modulating the proliferation and, possibly, the differentiation of the PA 16/23 cells.