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

ABSTRACT

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. 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. 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 [V beta2, V beta16, V beta21, V beta22] and the restricted-expression families [V beta14 and V beta17]. All the gene families of the control children only exhibited blur bands and polyclonal. 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