Document 0835
 DOCN  M9590835
 TI    Spontaneous generation of human CD8+ TCR alpha beta+ cells derived from
       precursors within the double negative compartment.
 DT    9509
 AU    Fujimiya Y; Nakayama M; Shibata T; Abe J; Shimada M; Kohsaka T; Division
       of Immunology, National Children's Medical Research; Center, Tokyo,
       Japan.
 SO    Immunol Cell Biol. 1995 Feb;73(1):33-7. Unique Identifier : AIDSLINE
       MED/95286201
 AB    Flow cytometric analysis demonstrated that fresh human thymocytes
       contain only a low level of mature CD8+ TCR alpha beta + or CD8+ TCR
       gamma delta + cells and they consist consist of approximately 70% double
       positive (DP) and approximately 10% double negative (DN) cells. These
       unfractionated thymocytes could be selectively expanded in vitro by
       stimulation with 12-O-tetradecanoylphorbol 13-acetate (TPA) and PHA in
       the presence of IL-2. The majority of the cells expanded from
       unfractionated thymocytes expressed CD3, TCR alpha beta and CD8
       molecules after long-term culture (18 days). When highly purified DN
       thymocytes were expanded over a period of 18 days in the presence of DP
       cells, they also co-expressed CD3, TCR alpha beta and CD8 molecules on
       their surface. However, when purified DN thymocytes were expanded alone,
       that is, in the absence of DP cells for 18 days, they expressed
       CD3-associated TCR gamma delta, but not CD8 or TCR alpha beta. Despite
       the expression of measurable levels of IL-2 alpha and beta receptors, as
       well as a significant level of TCR alpha beta, purified DP cells failed
       to proliferate. These findings provide the first evidence, in humans,
       that the progression of precursor cells in the DN compartment to a later
       stage of differentiation can be induced outside the thymus and that DP
       cells can affect the development of TCR expression in proliferating DN
       thymocytes.
 DE    Cell Differentiation/*IMMUNOLOGY  Cells, Cultured  Child  Child,
       Preschool  CD8-Positive T-Lymphocytes/*IMMUNOLOGY  Flow Cytometry  Human
       Infant  Receptors, Antigen, T-Cell, alpha-beta/*IMMUNOLOGY  Support,
       Non-U.S. Gov't  Thymus Gland/CYTOLOGY  JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).