Mechanisms of polyclonal tolerance induced by lipopolysaccharide and cyclophosphamide

Kondrat'eva, T. K.; Fontalin, L. N.; Mikheeva, N. V.; Holáň, Vladimı́r

doi:10.1007/bf00834974

Cited by 2 publications

(1 citation statement)

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“…Other experiments of ours, isolating mice in a sterile environment or using the selective decontamination, according to Mandel et al (1985), were not effective. Also, suppression of antibody producing cells, according to the methods of Kondratyeva et al (1987), did not influence the CFU-S proliferation in our mice.…”

Section: Discussionmentioning

confidence: 50%

Haemopoietic stem cells: spleen colony‐forming cells are normally actively proliferating

1990

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The haemopoietic stem cells forming spleen colonies (CFU-S) had on average 30 to 40% of cells engaged in the DNA synthesis in normal mice continuously over 4 years. A majority of experiments aimed at the suppression of the CFU-S proliferation, which included suppression of the T-lymphocytes by means of cyclosporin A or by adult thymectomy, administration of antibacterial and antifungal agents and maintainance of mice in a sterile environment, suppression of antibody-producing cells by a successive administration of the bacterial lipopolysaccharide and cyclophosphamide and attempts to increase the total number of CFU-S in the body through massive transfusions of bone marrow cells or by grafting plugs of the bone marrow under the kidney capsulae, have not been sufficiently effective. A transient suppression of CFU-S proliferation occurred during recovery of the haemopoietic tissue from damage caused by cyclophosphamide. The results support the view that changes in CFU-S numbers and in the proportion of them in DNA synthesis may be positively correlated when CFU-S numbers fluctuate physiologically about their normal values. The failure to manipulate the CFU-S proliferation rate easily suggests that proliferation of these cells may not be under a strong 'switch onswitch off' control.We have reported that haemopoietic stem cells, detected by the spleen colony-forming technique (CFU-S), vary considerably in their sensitivity to the lethal action of [3H]-thymidine or hydroxyurea when individual, normal mice were examined (NeEas & Znojil, 1987). The mean value of the proportion of DNA synthesizing CFU-S was about 30% in our normal mice, which is much higher than the widely accepted value of less than 10% (Lord, 1983). This paper summarizes our attempts to suppress CFU-S cycling in normal mice, which were largely ineffective. We present these observations to demonstrate the constancy of the CFU-S high proliferation rate in our normal mice and its resistance to experimental conditions that should, according to present concepts, decrease the CFU-S Proliferation. MATERIALS A N D M E T H O D SMice CBA/Ca mice, C57Bl/lOScSn mice, CBA/Ca x C57B1/1OScSn F1 hybrids (CBFI) and DBA 2/J x C57B1/1OScSn F1 hybrids (BDF1), all of the specific pathogen-free grade IV (according to

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Section: Discussionmentioning

confidence: 50%