RESUMO
An important subdivision of effector T cells can be made based on patterns of cytokine production and functional programs. Type 1 T cells produce IFN-gamma and protect against viral pathogens, whereas type 2 cells produce cytokines such as IL-4 and IL-5 and protect against large extracellular parasites. Both CD4(+) and CD8(+) T cells can be polarized into type 1 or type 2 cytokine-secreting cells, suggesting that both populations play a regulatory role in immune responses. In this study, we used high-density oligonucleotide arrays to produce a comprehensive picture of gene expression in murine CD4(+) Th1 and Th2 cells, as well as CD8(+) type 1 and type 2 T cells. Polarized type 1 and 2 cells transcribed mRNA for an unexpectedly large number of genes, most of which were expressed in a similar fashion between type 1 and type 2 cells. However, >100 differentially expressed genes were identified for both the CD4(+) and CD8(+) type 1 and 2 subsets, many of which have not been associated with T cell polarization. These genes included cytokines, transcription factors, molecules involved in cell migration, as well as genes with unknown function. The program for type 1 or type 2 polarization was similar for CD4(+) and CD8(+) cells, since gene expression patterns were roughly the same. The expression of select genes was confirmed using real-time PCR. The identification of genes associated with T cell polarization may give important insights into functional and phenotypic differences between effector T cell subsets and their role in normal responses and inflammatory disease.
Assuntos
Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Regulação da Expressão Gênica , Interferon gama/biossíntese , Interleucinas/biossíntese , Análise de Sequência com Séries de Oligonucleotídeos , Subpopulações de Linfócitos T/metabolismo , Animais , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Sistemas Computacionais , Etiquetas de Sequências Expressas , Perfilação da Expressão Gênica , Interferon gama/genética , Interleucinas/genética , Linfonodos/citologia , Camundongos , Camundongos Endogâmicos C57BL , Reação em Cadeia da Polimerase , RNA Complementar/análise , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Baço/citologia , Subpopulações de Linfócitos T/imunologia , Células Th1/imunologia , Células Th1/metabolismo , Células Th2/imunologia , Células Th2/metabolismoRESUMO
The potential for cross infection through dental amalgam carriers was investigated in 37 Dunedin dental practices and in the University of Otago School of Dentistry. Eighteen practitioners had autoclavable carriers, but only 2 autoclaved them at least daily. The School of Dentistry disinfected plastic carriers and autoclaved metal carriers. Microbiological examination, by culturing from the most commonly contaminated carrier site, showed that the School of Dentistry method for disinfection of plastic carriers was unreliable. Autoclaving was confirmed as the preferred method of sterilisation, but many existing carriers are not suited to this technique.