title: Thymocyte differentiation from lentivirus-marked CD34(+) cells in infant and adult human thymus.
abstract: Changes in thymic function and immune system homeostasis associated with HIV infection or chemotherapy have significant effects on the ability of patients to maintain a complete T cell receptor repertoire. Therefore, the development of in vitro systems to evaluate thymic function in children and adults may aid in the understanding of thymopoiesis and the development of new therapies to improve thymic output. Here we use a lentivirus-based gene transfer system to mark CD34(+) cells with EGFP and follow their differentiation into CD4(+) and CD8(+) single positive thymocytes in human thymic organ cultures. Lentivirus-marked cells entered the thymus and were detected in both the cortex and medulla. Pretreatment of the thymus with 2-deoxyguanosine depleted resident thymocytes and significantly increased the percentage of EGFP(+) thymocytes. High frequency gene transfer into CD34(+) cells and maintained expression throughout differentiation allows for the in vitro assessment of thymic function. In thymuses ranging in age from fetal to adult we observed EGFP(+) thymocytes at all stages of development suggesting that thymuses of all ages are capable of accepting new T cell progenitors and contributing to the maintenance of T cell homeostasis.
authors.affiliation: Division of Infectious Diseases Y9.206, Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9113, USA.
authors.forename: J T
authors.initials: JT
authors.lastname: Evans
authors.forename: Y
authors.initials: Y
authors.lastname: Okamoto
authors.forename: D C
authors.initials: DC
authors.lastname: Douek
authors.forename: R D
authors.initials: RD
authors.lastname: McFarland
authors.forename: J
authors.initials: J
authors.lastname: Gatlin
authors.forename: R A
authors.initials: RA
authors.lastname: Koup
authors.forename: J V
authors.initials: JV
authors.lastname: Garcia
mesh_terms: D000328:Adult; D018952:Antigens, CD34 / Q000378:metabolism*; D017252:CD3 Complex / Q000378:metabolism; D002454:Cell Differentiation; D046508:Culture Techniques; D003849:Deoxyguanosine; D005333:Fetus / Q000166:cytology / Q000276:immunology; D015329:Gene Rearrangement, T-Lymphocyte; D018014:Gene Transfer Techniques; D049452:Green Fluorescent Proteins; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016086:Lentivirus / Q000235:genetics; D008099:Liver / Q000166:cytology / Q000276:immunology; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008212:Lymphocyte Depletion; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism
chemical_list: D018952:Antigens, CD34; D017252:CD3 Complex; D008164:Luminescent Proteins; D011994:Recombinant Proteins; D049452:Green Fluorescent Proteins; D003849:Deoxyguanosine