T cell receptor repertoire in blood and skin of healthy volunteers with immunological memory to mycobacteria

This study aims to characterise the TCR repertoire of the tuberculin skin test, as model of an in vivo human mycobacterial challenge. Healthy volunteers with immunological memory to Mycobacterium tuberculosis antigens were identified using an interferon-? release assay of peripheral blood. Two units tuberculin or an equivalent volume of saline was injected into the forearm of study participants (n=10). After 72 hours, 3 mm skin punch biopsies were taken from the injection site. RNA, extracted from skin biopsies as well as from whole blood samples, was processed using a robust single strand DNA ligation protocol which tags each molecule of TCR alpha/beta mRNA with a unique molecular barcode before PCR amplification and sequencing.