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991.
Selective attraction of monocytes and T lymphocytes of the memory phenotype by cytokine RANTES. 总被引:101,自引:0,他引:101
An important process in the immune response is the migration of different populations of lymphocytes at the proper time to sites of antigenic challenge. Although several chemoattractants are known for broad classes of lymphocytes, such as T and B cells, the process by which lymphocytes of specific subsets, such as helper, cytotoxic or memory T cells, migrate to the appropriate sites remains obscure. Interleukin-8 is a chemoattractant for T cells and neutrophils and is a member of a superfamily of soluble molecules related by a conserved motif containing four cysteine residues. IL-8 and related molecules, including platelet factor 4, constitute the C-X-C class of the superfamily and a group of cytokines produced by haematopoietic cells constitute the RANTES/sis or C-C class. The roles of most of these molecules are not well known, although murine MIP-1 alpha of the C-C branch is a specific inhibitor of haematopoietic stem cell proliferation and some members of the C-X-C branch are neutrophil-targeted inflammatory agents. Here we report that the RANTES protein of the C-C class causes the selective migration of human blood monocytes and of T lymphocytes expressing the cell surface antigens CD4 and UCHL1. CD4+/UCHL1+T cells are thought to be prestimulated or primed helper T cells involved in memory T cell function. The preferential attraction of T-cell subsets by specific cytokines could in part explain how lymphocytes are targeted, and may provide insight into the workings of T cell memory. 相似文献
992.
G. O. Poinar Jr R. T. Hess W. Lanier S. Kinney J. H. White 《Cellular and molecular life sciences : CMLS》1989,45(2):191-192
A bacteriophage infective toXenorhabdus luminescens, a bacterial symbiont of heterorhabditid nematodes, was recovered from insects that supported poor nematode development. Plaque tests showed the phage particles to be infective only to primary and not secondary colonies ofX. luminescens. The phage was not infective toX. nenatophilus primaries or secondaries. The bacteriophage particles ranged 80–90 nm in length, with the head ranging from 40 to 50 nm in diameter. Restriction analysis was performed on isolated bacteriophage DNA. This first report of a bacteriophage fromXenorhabdus species has pratical implications since it could be detrimental to cultures ofHeterorhabditis nematodes that are being produced throughout the world for the biological control of insects. 相似文献
993.
T Tameyasu 《Experientia》1990,46(7):677-679
Changes in the profile of equatorial intensities of X-ray diffraction from an intact, anterior byssal retractor muscle (ABRM) of Mytilus were examined at rest, during contracture brought about by acetylcholine (ACh) and a subsequent rigor-like contraction caused by raising the tonicity of the external solution, and after returning the tonicity to normal. The results suggest that the cross-bridges formed between thick and thin actin filaments during the ACh-contracture were maintained in the hypertonic solution and broken on decreasing the tonicity before the recovery of spacing of the actin filament lattice. A similar rigor-like contraction was induced in glycerinated ABRM by increasing salt concentration during active contraction. The rigor-like force declined rapidly when Ca++ concentration decreased. The results suggest that the detachment of the cross-bridge from the actin filament is regulated by Ca++ at high ionic strength in the ABRM. 相似文献
994.
Binding of myosin I to membrane lipids 总被引:39,自引:0,他引:39
The single-headed myosins called myosin-I were first isolated from the protozoan Acanthamoeba and subsequently identified in other cells. We previously reported evidence that myosin-I is responsible for the movement of membranes, extracted from Acanthamoeba, along actin filaments in vitro. Here we show for the first time that myosin-I can bind directly to NaOH-extracted membranes isolated from Acanthamoeba and to vesicles of pure lipids with an affinity sufficient for extensive binding in the cell. Membrane-bound myosin-I may provide a mechanism for many cellular movements previously thought to involve filamentous myosin-II. 相似文献
995.
A. W. T. Konings 《Cellular and molecular life sciences : CMLS》1971,27(3):253-254
Résumé Les expériences présentées montrent que dans les noyaux isolés du thymus de rat l'inhibition de glycéraldehyde-phosphate déhydrogénase stimule la production de14CO2 de (6-14C) glucose. Un méchanisme capable d'expliquer cet effet est proposé et discuté. 相似文献
996.
T W Stone 《Experientia》1973,29(6):666-667
997.
998.
M. Jakóbisiak M. Kamiński A. E. Kossakowska T. Rymaszewska-Kossakowska 《Cellular and molecular life sciences : CMLS》1973,29(3):335-336
Zusammenfassung Nachweis eines Hemmeffektes immunosupressiver Mittel (Cortison, Cyclophosphamide und Immuran) bei Mäusen nach UV-Bestrahlung auf die hämopoetische Regeneration (Milzkolonien und Knochenmarkzellen). 相似文献
999.
1000.