This may be because the presence and localization of polyfunctional T-cells at infection seem crucial as high numbers in the lung shortly after infection are protective by their capacity to restrict bacterial replication and thus promote clearance or successful containment. In this regard, one might argue, that in case of reinfection, QFT consistent positives are more likely than reverters to have adequate numbers of circulating memory T-cells capable of rapid elimination/containment of new MTB bacilli. On the other hand, mouse models suggest that repeated mycobacterial exposure in already MTB infected mice increased the lung damage independent of the expression of IFNc in the lesion. The QFT assay measures the total 5alpha-Pregnan-3alpha-ol-20-one production of IFNc in response to three MTB-specific antigens and does not differentiate between different types of cytokine-producing T-cells. As we report good correlation between the magnitude of the QFT response and the PD 168,077 maleate salt absolute frequencies of PPD-specific polyfunctional CD4+ T-cells, the rather simple QFT assay, seems, in fact, a good surrogate marker for the numbers of mycobacteria-specific polyfunctional T-cells in peripheral blood of LTBI individuals. This finding questions the rationale for performing elaborate flow cytometry assays on peripheral blood samples in the search for ����protective biomarkers����. The finding that QFT levels correlated well with the total number of PPDspecific IFNc-producing T-cells further strengthens the validity of our results, and suggests little interference by BCG-vaccination and NTM-exposure. Notably, BCG-vaccination at birth has little influence on the TST response. The RNA world is appearing more and more complex and deciphering the growing list of RNA species, isoforms and byproducts is a major challenge in biology. Genome annotation algorithms are still limited and full-length cDNAs or RACE PCR remain essential for studying the structure and function of the genes. These approaches are widely used for single gene as well as large-scale genomic programs. The main limitation full-length cDNA or 59 RACE methods try to resolve is binding a known sequence at the cap site, so as to prime second-strand polymerization of the cDNA.