Induced pluripotent stem cells (iPSCs) hold enormous potential for the development of personalized in vitro disease models, genomic health analyses, and autologous cell therapy. Here we describe the generation of T lymphocyte-derived iPSCs from small, clinically advantageous volumes of non-mobilized peripheral blood. These T-cell derived iPSCs (“TiPS”) retain a normal karyotype and genetic identity to the donor. They share common characteristics with human embryonic stem cells (hESCs) with respect to morphology, pluripotency-associated marker expression and capacity to generate neurons, cardiomyocytes, and hematopoietic progenitor cells. Additionally, they retain their characteristic T-cell receptor (TCR) gene rearrangements, a property which could be exploited for iPSC clone tracking and T-cell development studies. Reprogramming T-cells procured in a minimally invasive manner can be used to characterize and expand donor specific iPSCs, and control their differentiation into specific lineages.

One-third of the world's population is infected with Mycobacterium tuberculosis, the causative agent of human tuberculosis, with an annual death rate of more than 2 million (8). Treatment regimens are effective in only 60 to 90% of patients with persistent infection (14). In humans, tuberculosis can be divided into three phases (28): an active phase, characterized by initial replication of M. tuberculosis that triggers host cellmediated immunity; a chronic phase, in which infected individuals are not infectious, with undetectable levels of tuberculous bacilli; and finally, a reactivation phase, which occurs in 10% of patients with an intact immune system. The reactivation rate is even higher for immune-suppressed individuals (19). Both in vitro and in vivo models have been used to investigate tuberculosis during the dormancy and reactivation phases in humans. One of the first in vitro models of tuberculosis dormancy was established by Wayne (49,50) and is based on culturing M. tuberculosis under decreasing concentrations of oxygen levels, creating a microaerophilic environment where mycobacteria transform into a nonreplicating persistent form.More in vitro models were developed to study chronic tuberculosis, and they have shown that the host microenvironment is rich in reactive nitrogen intermediates (29, 48) but deficient in nutrients necessary for bacterial survival (5), suggesting that tuberculous bacilli persist in a metabolically inactive form. For in vivo studies, the mouse model of chronic and reactivation stages of tuberculosis was used to profile the immunological responses activated during both phases (9, 34). Using an artificial-granuloma implant in mice, the DosR regulon was shown to play a role in mycobacterial entry into the dormant phase, with the involvement of relA (20). Unfortunately, the main genetic bases of the mycobacterial conversion from the "dormant" to the "replicating" phase in the lungs has remained largely unknown. In this report, we communicate our efforts to investigate both the chronic and reactivation phases of tuberculosis.A key question relevant to tuberculosis is the physiological status of M. tuberculosis during different stages of infection. The work of different groups (27, 39) using quantitative PCR on both the genomic and transcriptional levels indicated that mycobacterial bacilli persist at a constant level with a very low growth rate. However, many questions related to chronic tuberculosis remain unanswered. Does the low growth rate mean that the bacilli are metabolically inactive? Can the mycobacterial bacilli sense the surrounding microenvironment? Also, do mycobacterial bacilli adapt to the change in their microen-* Corresponding author. Mailing address: