Biomaterial Database

Intermediate steps in thymic positive selection. Generation of CD4-8+ T cells in culture from CD4+8+, CD4int8+, and CD4+8int thymocytes with up-regulated levels of TCR-CD3. 1995

R Kydd, and K Lundberg, and D Vremec, and A W Harris, and K Shortman

Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia.

Minor thymus subpopulations representing possible intermediates in thymic positive selection were isolated by cell sorting from bcl-2 transgenic mice, and cultured 1 to 4 days in simple medium to assess their ability to spontaneously develop the surface phenotype of mature T cells. Recovery of cells was in the 60 to 80% range, and no cell proliferation occurred. Only cells originally expressing high, near mature T cell levels of CD3 developed further in culture by down-regulation of CD4 or CD8. The main mature cell product was CD4-8+, regardless of whether the starting phenotype of the CD3high intermediates was CD4+8+, CD4int8+, or CD4+8int; only an intermediate subpopulation expressing the highest levels of CD4 (CD4high8int) produced a dominance of CD4+8- mature progeny. Partial down-regulation of CD8 was therefore not a good indicator of CD4+ T lineage commitment. These and previous results indicate that maturation to the CD8+ T lineage involves a rapid up-regulation of the TCR-CD3 complex, but a relatively slow down-regulation of CD4; it may also involve a partial, transient reduction in surface CD8. In contrast, maturation to the CD4+ T lineage involves a relatively rapid down-regulation of CD8, with maintenance of high levels of CD4. There appears to be a marked asymmetry in the developmental steps leading from CD4+8+ thymocytes to the CD8+ or to the CD4+ T cell lineage.

UI	MeSH Term	Description	Entries
D008213	Lymphocyte Activation	Morphologic alteration of small B LYMPHOCYTES or T LYMPHOCYTES in culture into large blast-like cells able to synthesize DNA and RNA and to divide mitotically. It is induced by INTERLEUKINS; MITOGENS such as PHYTOHEMAGGLUTININS, and by specific ANTIGENS. It may also occur in vivo as in GRAFT REJECTION.	Blast Transformation,Blastogenesis,Lymphoblast Transformation,Lymphocyte Stimulation,Lymphocyte Transformation,Transformation, Blast,Transformation, Lymphoblast,Transformation, Lymphocyte,Activation, Lymphocyte,Stimulation, Lymphocyte
D008810	Mice, Inbred C57BL	One of the first INBRED MOUSE STRAINS to be sequenced. This strain is commonly used as genetic background for transgenic mouse models. Refractory to many tumors, this strain is also preferred model for studying role of genetic variations in development of diseases.	Mice, C57BL,Mouse, C57BL,Mouse, Inbred C57BL,C57BL Mice,C57BL Mice, Inbred,C57BL Mouse,C57BL Mouse, Inbred,Inbred C57BL Mice,Inbred C57BL Mouse
D008822	Mice, Transgenic	Laboratory mice that have been produced from a genetically manipulated EGG or EMBRYO, MAMMALIAN.	Transgenic Mice,Founder Mice, Transgenic,Mouse, Founder, Transgenic,Mouse, Transgenic,Mice, Transgenic Founder,Transgenic Founder Mice,Transgenic Mouse
D011518	Proto-Oncogene Proteins	Products of proto-oncogenes. Normally they do not have oncogenic or transforming properties, but are involved in the regulation or differentiation of cell growth. They often have protein kinase activity.	Cellular Proto-Oncogene Proteins,c-onc Proteins,Proto Oncogene Proteins, Cellular,Proto-Oncogene Products, Cellular,Cellular Proto Oncogene Proteins,Cellular Proto-Oncogene Products,Proto Oncogene Products, Cellular,Proto Oncogene Proteins,Proto-Oncogene Proteins, Cellular,c onc Proteins
D002454	Cell Differentiation	Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.	Differentiation, Cell,Cell Differentiations,Differentiations, Cell
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013950	Thymus Gland	A single, unpaired primary lymphoid organ situated in the MEDIASTINUM, extending superiorly into the neck to the lower edge of the THYROID GLAND and inferiorly to the fourth costal cartilage. It is necessary for normal development of immunologic function early in life. By puberty, it begins to involute and much of the tissue is replaced by fat.	Thymus,Gland, Thymus,Glands, Thymus,Thymus Glands
D015496	CD4-Positive T-Lymphocytes	A critical subpopulation of T-lymphocytes involved in the induction of most immunological functions. The HIV virus has selective tropism for the T4 cell which expresses the CD4 phenotypic marker, a receptor for HIV. In fact, the key element in the profound immunosuppression seen in HIV infection is the depletion of this subset of T-lymphocytes.	T4 Cells,T4 Lymphocytes,CD4-Positive Lymphocytes,CD4 Positive T Lymphocytes,CD4-Positive Lymphocyte,CD4-Positive T-Lymphocyte,Lymphocyte, CD4-Positive,Lymphocytes, CD4-Positive,T-Lymphocyte, CD4-Positive,T-Lymphocytes, CD4-Positive,T4 Cell,T4 Lymphocyte
D015854	Up-Regulation	A positive regulatory effect on physiological processes at the molecular, cellular, or systemic level. At the molecular level, the major regulatory sites include membrane receptors, genes (GENE EXPRESSION REGULATION), mRNAs (RNA, MESSENGER), and proteins.	Receptor Up-Regulation,Upregulation,Up-Regulation (Physiology),Up Regulation
D016176	T-Lymphocyte Subsets	A classification of T-lymphocytes, especially into helper/inducer, suppressor/effector, and cytotoxic subsets, based on structurally or functionally different populations of cells.	T-Cell Subset,T-Cell Subsets,T-Lymphocyte Subset,Subset, T-Cell,Subset, T-Lymphocyte,Subsets, T-Cell,Subsets, T-Lymphocyte,T Cell Subset,T Cell Subsets,T Lymphocyte Subset,T Lymphocyte Subsets