The T-cell antigen receptor: methods of study and relevance in the pathogenesis of pulmonary disorders.
Each antigen (Ag)-driven immune reaction begins with Ag recognition by T-lymphocytes through a surface molecular structure and T-cell antigen receptor (TCR). TCR is a proteid heterodimer, composed of an alpha and a beta chain (alpha beta+ T-cells) or of a gamma and a delta chain (gamma delta+ T-cells); each TCR chain is composed of two subunits the constant (C) region and the variable (V) region, whose combination is responsible, at least in part, for Ag specificity of each T-cell. Immune reactions toward known (e.g. tuberculosis) or unknown (e.g. sarcoidosis). Ags play an important role in the pathogenesis of many pulmonary disorders. The study of TCR may be performed at DNA, RNA and protein levels, applying molecular biology techniques. Using this molecular approach, it has been demonstrated, for example, that subgroups of patients have increased proportions of lung and/or blood T-cells bearing TCR with certain V regions of the alpha beta+ T-cells or of the gamma delta+ T-cells, suggesting that these cells were reacting toward antigenic stimuli. Similar results were obtained in tuberculosis, where an increase in gamma delta+ T-cells have been observed in peripheral blood of some patients. In asthma and in lung cancer a characterisation of TCRs of T-cells reacting to the involved allergens or to the tumour-associated Ags is still lacking, although animal studies show a selection of allergen-specific TCRs among the airway T-cells, and the ability of tumour-infiltrating gamma delta+ T-cells to kill cancer cells.(ABSTRACT TRUNCATED AT 250 WORDS)
Balbi
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Divisione de Pneumologia, Ospedale S. Andrea, La Spezia, Italy.
D006801:Humans; D008171:Lung Diseases / Q000276:immunology*; D011948:Receptors, Antigen, T-Cell / Q000235:genetics / Q000276:immunology*
D011948:Receptors, Antigen, T-Cell