scholarly journals Human CD3+ T lymphocytes that express neither CD4 nor CD8 antigens.

1986 ◽  
Vol 164 (1) ◽  
pp. 339-344 ◽  
Author(s):  
L L Lanier ◽  
J J Ruitenberg ◽  
J H Phillips
Keyword(s):  
T Cells ◽  
T Lymphocytes ◽  
Peripheral Blood ◽  
Human Peripheral Blood ◽  
Cytotoxic T Cells ◽  
Low Frequency ◽  
Normal Peripheral Blood ◽  
Normal Human ◽  
Normal Human Peripheral Blood

CD3+ T lymphocytes expressing neither CD4 nor CD8 antigens exist in normal human peripheral blood in low frequency (approximately 3% of lymphocytes). The CD3+,4-,8- phenotype was stably maintained after in vitro culture in IL-2. Culture of CD3+,4-,8- cells in only rIL-2 generated cytotoxic T cells that lysed NK-sensitive and NK-insensitive tumor cell targets without MHC restriction. These experiments clearly show that phenotypically and functionally competent T cells expressing neither CD4 nor CD8 are present in normal peripheral blood.

Ranitidine Fails to Suppress the Growth in vitro of Haemopoietic Progenitors from Human Peripheral Blood or Bone Marrow

1989 ◽  
Vol 8 (1) ◽  
pp. 19-22
Author(s):  
C.D.L. Reid ◽  
A. Kirk
Keyword(s):  
Bone Marrow ◽  
Drug Concentration ◽  
Peripheral Blood ◽  
Human Peripheral Blood ◽  
Erythroid Progenitors ◽  
Drug Concentrations ◽  
Normal Human ◽  
Normal Human Peripheral Blood ◽  
Clonal Assays

Ranitidine was added in various concentrations (25-1600 ng/ml) to clonal assays of haemopoietic progenitors of normal human peripheral blood or bone marrow. Although a significant reduction in colonies forming from granulocyte-macrophage progenitors (CFU-GM) was demonstrated at the lowest drug concentration, no significant growth suppression was seen at higher concentrations. There was no evidence for growth inhibition of either erythroid progenitors (BFU-E) or pluripotent progenitors (CFU-mix) at any of the drug concentrations studied. A direct toxic effect of ranitidine on normal haemopoietic progenitors thus appears an unlikely cause of cytopenias observed during treatment.

scholarly journals The Transfer RNA Methylases of Human Lymphocytes. I. Induction by PHA in Normal Lymphocytes

Blood ◽  
1971 ◽  
Vol 37 (3) ◽  
pp. 282-292 ◽  
Author(s):  
DAVID H. RIDDICK ◽  
ROBERT C. GALLO
Keyword(s):  
Peripheral Blood ◽  
Human Peripheral Blood ◽  
Human Lymphocytes ◽  
Peripheral Blood Lymphocytes ◽  
Transfer Rna ◽  
Normal Peripheral Blood ◽  
Blood Lymphocytes ◽  
Normal Human ◽  
Total Capacity ◽  
Normal Human Peripheral Blood

Abstract Assays were performed that measured both the rate and extent (or total capacity) of transfer RNA methylases in extracts of lymphocytes cultured in the presence and absence of phytohemagglutinin (PHA). The tRNA methylases of human peripheral blood lymphocytes undergoing blastogenesis in culture with PHA had a five- to sixfold increase in rate and a three- to sevenfold increase in extent of methylation of heterologous tRNA. These data suggest that PHA transformed lymphocytes not only contain elevated levels of tRNA methylases, but that the increase includes qualitatively different enzymes from those found in normal peripheral blood lymphocytes. Experiments in which lymphocytes were incubated for various times with PHA revealed that tRNA methylase induction occurred late in or after DNA synthesis and after morphologic transformation, but prior to mitosis. Rate and extent of tRNA methylation increased simultaneously. PHA induction of tRNA methylase activity was dependent on the synthesis of new RNA in lymphocytes cultured from 40 to 45 hours. The increase was not due to different levels of inhibitors or activators or preferential degradation of reaction components. The data suggest that quantitative and qualitative changes occur in the tRNA methylases of the normal human peripheral blood lymphocyte stimulated by PHA to undergo transition to an undifferentiated cell "in cycle." The possible significance of these findings to control of protein synthesis in PHA transformed lymphocytes is discussed.

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