Comparing TCR beta chain variable gene profile skewness between children with tuberculosis and BCG-vaccinated children.

BACKGROUND We compared the T cell antigen receptor (TCR-BV) gene families of peripheral blood mononuclear cells (PMBC) between children with tuberculosis (TB) and those inoculated with the Bacille Calmette Guerin (BCG) vaccine. METHODS The total RNA was extracted from PMBC of 15 TB children, 15 BCG-vaccinated children and 15 healthy controls. The RNAs were reverse-transcribed and amplified by polymerase chain reaction (PCR). PCR products were separated on 1.5% agarose gel and analyzed with the Genescan technique. RESULTS Some TCR-BV gene families in TB children and BCG-vaccinated children exhibited a blur band in the predicted position on 1.5% agarose gel, some showed a distinct or fainted band. In general, many shared predominant clonal TCR-BV gene families (Vβ2, Vβ16, Vβ21, Vβ22) and the restricted-expression families (Vβ14 and Vβ17). All the gene families of the control children only exhibited blur bands and polyclonal. CONCLUSIONS The skewed profile of TCR-BV gene families in TB children and BCG-vaccinated children are similar, which may probably explain the protective effects of BCG-vaccine against TB in children.