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We show that a gene introduced into cells of mouse embryos by a retrovirus can serve as a heritable marker for the study of cell lineage in vivo. We constructed a defective recombinant retrovirus in which the Escherichia coli beta-galactosidase (lacZ) gene is inserted in the genome of a Muloney murine leukemia virus (M-MuLV). Expression of lacZ was detected(More)
Contact sensitivity (CS) is a form of delayed-type hypersensitivity to haptens applied epicutaneously and is thought to be mediated, like classical delayed-type hypersensitivity responses, by CD4+ T helper-1 cells. The aim of this study was to identify the effector T cells involved in CS. We studied CS to the strongly sensitizing hapten dinitrofluorobenzene(More)
The Escherichia coli lacZ gene has been used as an indicator gene for the study of cell lineage in vivo. To adapt this marker for gene expression studies, a sequence encoding a modified beta-galactosidase and including the simian virus 40 large tumor nuclear location signal (nls-beta-Gal) has been introduced into vectors. In differentiated cells,(More)
We demonstrate that individual cells infected with and expressing a recombinant retrovirus carrying the Escherichia coli beta-galactosidase gene (lacZ) can be viably stained, analyzed, sorted, and cloned by fluorescence-activated cell sorting based on the levels of lacZ expressed. To accomplish this we have devised a method to enzymatically generate and(More)
BACKGROUND Photodamage is characterized by degradation of collagen and accumulation of abnormal elastin in the superficial dermis. Mast cells and macrophages, which are found in higher numbers in photoaged skin, have been implicated in this process. OBJECTIVES To analyse the phenotype of haematopoietic-derived infiltrating cells in photodamaged skin. (More)
We have previously reported that contact sensitivity (CS) to dinitrofluorobenzene (DNFB) in C57BL/6 mice was mediated by MHC class I-restricted CD8+ T cells and down-regulated by MHC class II-restricted CD4+ T cells. In this study, we analyzed the contribution of dendritic cells (DC) in the induction of these two T cell subsets endowed with opposite(More)
The mitochondrial intron-encoded endonuclease I-SceI of Saccharomyces cerevisiae has an 18-bp recognition sequence and, therefore, has a very low probability of cutting DNA, even within large genomes. We demonstrate that double-strand breaks can be initiated by the I-SceI endonuclease at a predetermined location in the mouse genome and that the breaks can(More)
A quantitative bioassay for human immunodeficiency viruses has been developed on the basis of the ability of the tat gene to transactivate the expression of an integrated beta-galactosidase gene in a HeLa-CD4+ cell line. Infection by a single virion of HIV-1 or HIV-2 corresponds to a unique blue syncytium or a cell cluster detected after fixation and(More)
Allergic contact dermatitis (ACD), one of the commonest occupational diseases, is a T-cell-mediated skin inflammation caused by repeated skin exposure to contact allergens, i.e. nonprotein chemicals called haptens. Allergic contact dermatitis, also referred to as contact hypersensitivity, is mediated by CD8+ T cells, which are primed in lymphoid organs(More)
BACKGROUND Chronic exposure to ultraviolet (UV) radiation induces changes in the skin structure which are mostly found in the superficial dermis and at the dermal-epidermal junction. Keratinocytes and fibroblasts contribute both to the synthesis and to the degradation of the molecules important for the integrity of this skin site. While several studies have(More)