Doherty Institute - Research Publications
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ItemThe interaction of macrophage and non-macrophage tropic isolates of HIV-1 with thymic and tonsillar dendritic cells in vitro(ROCKEFELLER UNIV PRESS, 1996-04-01)Dendritic cells isolated from thymus and tonsil were tested for susceptibility to HIV-1 strains that are tropic for macrophages or for T cell lines. DCs were purified by cell sorting and before infection expressed high levels of CD4 and HLA-DR and lacked markers for T, B, NK cells, or macrophages. Viral entry and reverse transcription was found after pulsing with strains of HIV-1 that could infect macrophages. During the first 36 h the PCR signals for gag sequences increased in DCs and macrophages. In contrast little if any viral DNA was found after pulsing macrophages or DCs with HIV-1 that was able to infect T cell lines. DCs pulsed with HIV-1 were able to transmit infection to responding T cells during an allogeneic or superantigen response. Selection for virus able to infect lymphoid DCs and other DCs expressing CD4 and its transfer to T cells during subsequent immune responses may provide a mechanism for the observed predominance of macrophage-tropic HIV-1 after in vivo transmission.
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ItemDENDRITIC CELLS FRESHLY ISOLATED FROM HUMAN BLOOD EXPRESS CD4 AND MATURE INTO TYPICAL IMMUNOSTIMULATORY DENDRITIC CELLS AFTER CULTURE IN MONOCYTE-CONDITIONED MEDIUM(ROCKEFELLER UNIV PRESS, 1993-09-01)A procedure has been developed to isolate dendritic cells to a high degree of purity from fresh blood. Prior enrichment methods have relied upon an initial 1-2-d culture period. Purified fresh isolates lack the characteristic morphology, phenotype, and immunostimulatory function of dendritic cells. The purified cells have the appearance of medium sized lymphocytes and express substantial levels of CD4, but lack the T cell molecules CD3, CD8, and T cell receptor. When placed in culture, the cells mature in a manner resembling the previously described, cytokine-dependent maturation of epidermal dendritic cells (Langerhans cells). The cells enlarge and exhibit many cell processes, express much higher levels of major histocompatibility complex class II and a panel of accessory molecules for T cell activation, and become potent stimulators of the mixed leukocyte reaction. Among the many changes during this maturation process are a fall in CD4 and the appearance of high levels of B7/BB1, the costimulator for enhanced interleukin 2 production in T cells. These changes are not associated with cell proliferation, but are dependent upon the addition of monocyte-conditioned medium. We suggest that the freshly isolated CD4-positive blood dendritic cells are recent migrants from the bone marrow, and that subsequent maturation of the lineage occurs in tissues in situ upon appropriate exposure to cytokines.
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ItemDIFFERENCES IN GENE COPY NUMBER CARRIED BY DIFFERENT MHC ANCESTRAL HAPLOTYPES - QUANTITATION AFTER PHYSICAL SEPARATION OF HAPLOTYPES BY PULSED FIELD GEL-ELECTROPHORESIS(ROCKEFELLER UNIV PRESS, 1990-06-01)We have examined the hypothesis that MHC ancestral haplotypes have a specific content of genes regulating the extent of autoimmune reactions. Gene copy number was quantitated by objective densitometry after PFGE was used to separate heterozygous AHs of different lengths. Initially we analyzed examples of known gene copy number at the C4 and 21 hydroxylase loci and showed that the approach provides predictable results. We then studied heterozygotes containing one characterized and one uncharacterized AH with particular attention to the gene copy number at the C4, Cyp21, and DRB loci. Each AH studied has a characteristic gene copy number at each locus studied. The same may be true of TNF, but other possibilities must be considered. AHs are markers for extensive chromosomal segments including particular numbers of several functional genes. Since AHs mark susceptibility to autoimmune disease, differences in gene copy number may be implicated.