scholarly journals STUDIES ON RABBIT LYMPHOCYTES IN VITRO

1965 ◽  
Vol 122 (2) ◽  
pp. 423-440 ◽  
Author(s):  
Stewart Sell ◽  
P. G. H. Gell
Keyword(s):  
Dna Synthesis ◽  
Significant Degree ◽  
Blast Transformation ◽  
Donor Cells ◽  
Blast Cells ◽  
Rabbit Lymphocytes ◽  
Directed Transformation ◽  
The Given ◽  
Stimulation Of

Rabbit lymphocytes may be stimulated in vitro with specific antiallotype sera to transform into "blast" cells and to synthesize DNA. This transformation only occurs when the donor cells are obtained from a rabbit having a given γ-globulin allotype (As4) and these cells are cultured in the presence of an antiserum prepared against the given allotype (As4). Heterologous (sheep, goat, and guinea pig) anti-rabbit γ-globulin sera also induce significant blast transformation and DNA synthesis in rabbit lymphocytes. Allotypic transformation and DNA synthesis are due to 7S antiallotype antibodies and do not require complement. The degree of transformation and rate of DNA synthesis is related to the concentration of antibody. Incubation of the appropriate cells with the antiallotype antibody for as short a time as 15 minutes results in a significant degree of "blast" transformation, indicating that the recognition of the antiallotype specificity in the cells and stimulation of the cellular changes leading to eventual transformation is rapid. The activity of the antiallotype sera as measured by transforming or haemagglutinating capacity, may be absorbed by lymphocytes of the appropriate allotype, but is not absorbed by lymphocytes from a donor rabbit not having the allotype to which the antiserum is directed. Transformation does not occur with mixtures of lymphocytes from different rabbits even if 1 donor is immunized against an allotype present in the other donor. Peripheral rabbit lymphocytes can also be induced to undergo "blast transformation" in vitro by phytohaemagglutinin and staphylococcal filtrate. The lack of demonstrable leucoagglutinins in staphylococcal filtrate and antiallotype serum indicates that agglutination is not a necessary prerequisite to the induction of blast transformation.

scholarly journals STUDIES ON RABBIT LYMPHOCYTES IN VITRO

1965 ◽  
Vol 122 (4) ◽  
pp. 813-821 ◽  
Author(s):  
P. G. H. Gell ◽  
Stewart Sell
Keyword(s):  
Dna Synthesis ◽  
Blast Transformation ◽  
Summation Effect ◽  
Rabbit Igg ◽  
Lymphocyte Cultures ◽  
Specific Antisera ◽  
Rabbit Lymphocytes ◽  
Polypeptide Chains ◽  
Double Homozygote

Specific antisera directed against all six of the well characterised allotypic determinants of rabbit IgG (As1, 2, 3, 4, 5, and 6) are capable of inducing blast transformation and DNA synthesis when added to lymphocyte cultures obtained from donor rabbits having the appropriate IgG allotype. Mixtures of antisera directed against two different allotypic determinants induce a "summation" of transformation and DNA synthesis over and above the effect of mixtures of two antisera directed against the same allotypic determinant. This summation effect is observed regardless of whether the antisera which have been mixed are directed against allotypic determinants controlled by the same locus or by different loci. The finding that summation occurs with mixtures of two antisera directed against both the allotypic determinants of a double homozygote rabbit (As1, 6) suggests that lymphocytes from the peripheral blood may be primed to produce only one or the other of the two polypeptide chains of IgG, but not both.

Thrombopoietin-Induced Stimulation of Megakaryocyte- Enriched Bone Marrow Cultures

1979 ◽  
Author(s):  
K. L. Kellar ◽  
B. L. Evatt ◽  
C. R. McGrath ◽  
R. B. Ramsey
Keyword(s):  
Bone Marrow ◽  
Dna Synthesis ◽  
Bone Marrow Cells ◽  
Rabbit Plasma ◽  
Bone Marrow Cultures ◽  
Plasma Fractions ◽  
Marrow Cultures ◽  
Stimulation Of

Liquid cultures of bone marrow cells enriched for megakaryocytes were assayed for incorporation of 3H-thymidine (3H-TdR) into acid-precipitable cell digests to determine the effect of thrombopoietin on DNA synthesis. As previously described, thrombopoietin was prepared by ammonium sulfate fractionation of pooled plasma obtained from thrombocytopenic rabbits. A control fraction was prepared from normal rabbit plasma. The thrombopoietic activity of these fractions was determined in vivo with normal rabbits as assay animals and the rate of incorporation of 75Se-selenomethionine into newly formed platelets as an index of thrombopoietic activity of the infused material. Guinea pig megakaryocytes were purified using bovine serum albumin gradients. Bone marrow cultures containing 1.5-3.0x104 cells and 31%-71% megakaryocytes were incubated 18 h in modified Dulbecco’s MEM containing 10% of the concentrated plasma fractions from either thrombocytopenic or normal rabbits. In other control cultures, 0.9% NaCl was substituted for the plasma fractions. 3H-TdR incorporation was measured after cells were incubated for 3 h with 1 μCi/ml. The protein fraction containing thrombopoietin-stimulating activity caused a 25%-31% increase in 3H-TdR incorporation over that in cultures which were incubated with the similar fraction from normal plasma and a 29% increase over the activity in control cultures to which 0.9% NaCl had been added. These data suggest that thrombopoietin stimulates DNA synthesis in megakaryocytes and that this tecnique may be useful in assaying thrombopoietin in vitro.

scholarly journals Primary generation of cytolytic T lymphocytes in the absence of DNA synthesis.

1979 ◽  
Vol 150 (1) ◽  
pp. 196-201 ◽  
Author(s):  
H R MacDonald ◽  
R K Less
Keyword(s):  
T Lymphocytes ◽  
Dna Synthesis ◽  
Cytolytic Activity ◽  
Target Cells ◽  
Cytolytic T Lymphocytes ◽  
Spleen Cells ◽  
Con A ◽  
A Cell ◽  
Stimulation Of

The requirement for DNA synthesis during the primary differentiation of cytolytic T lymphocytes (CTL) had been investigated. CTL were induced polyclonally in vitro by stimulation of normal C57BL/6 spleen cells with concanavalin A (Con A)and their cytolytic activity was tested against 51Cr-labeled target cells in the presence of Bacto Phytohemagglutinin M. With this system, CTL activity could first be detected 48 h after exposure of spleen cells to Con A. Addition of cytosine arabinoside at concentrations sufficient to reduce DNA synthesis by 95-98% in Con A-stimulated cultures did not significantly inhibit the generation of cytolytic activity on a cell-to-cell basis. These results demonstrate that derepression of the genetic information required for the expression of CTL function can occur in the absence of detectable DNA synthesis.

Stimulation of cell division and DNA replication inPrototheca richardsiby passage through larval amphibian guts

Parasitology ◽  
1993 ◽  
Vol 107 (2) ◽  
pp. 119-124 ◽  
Author(s):  
T. J. C. Beebee ◽  
A. L.-C. Wong
Keyword(s):  
Cell Division ◽  
Dna Replication ◽  
Growth Inhibition ◽  
Dna Synthesis ◽  
Free Living ◽  
Leucine Uptake ◽  
Amphibian Larvae ◽  
Larval Amphibian ◽  
Stimulation Of

SUMMARYPrototheca richardsi, an unpigmented heterotrophic alga, causes growth inhibition in amphibian larvae and has proved refractory to culturein Vitro.P. richardsireplication is dependent on regular passaging through tadpole digestive systems; uptake of thymidine by free-livingProtothecacells and incorporation into DNA are very low by comparison with leucine uptake and incorporation into protein, but DNA synthesis is detectable in cells isolated from tadpole intestines. DNA replication was elicited 6–8 h after ingestion in protothecans fed to tadpoles and subsequently re-isolated from them, providing that the tadpoles were fed subsequent to the ingestion. It appears that passaging through tadpole intestines provides an essential stimulus to maintaining an active cell division cycle inP. richardsi.

Effects of ACTH and ACTH fragments on DNA synthesis in guinea-pig adrenal segments kept in organ culture

1987 ◽  
Vol 115 (3) ◽  
pp. 505-510 ◽  
Author(s):  
N. M. Wulffraat ◽  
H. A. Drexhage ◽  
P. Jeucken ◽  
R. D. van der Gaag ◽  
W. M. Wiersinga
Keyword(s):  
Guinea Pig ◽  
Organ Culture ◽  
Dna Synthesis ◽  
Intermediate Lobe ◽  
Terminal Part ◽  
Terminal Fragment ◽  
Acth Fragments ◽  
Epidermal Growth ◽  
Stimulation Of

ABSTRACT Stimulation of adrenal DNA synthesis by ACTH(1–39) and its fragments ACTH(1–24) (Synacthen) and ACTH(18–39) was investigated. Synthesis of DNA was measured as the increase in the percentage of cells in S-phase (Feulgen densitometry) in guinea-pig adrenal explants kept in organ culture and exposed to the peptides for 5 h at 37 °C. ACTH(1–39) and its C-terminal fragment ACTH(18–39) (corticotrophin-like intermediate lobe peptide) were found to be potent stimulators of in-vitro adrenal DNA synthesis. The dose–response kinetics were biphasic and optimal responsiveness was reached in both instances at 1 fmol/1–10 pmol/l (this biological effect of ACTH(18–39) has hitherto not been described). The N-terminal fragment ACTH(1–24) gave only minimal responses. Thyrotrophin and LH, tested as controls, did not induce adrenal DNA synthesis. Epidermal growth factor was a potent stimulator of adrenal DNA synthesis in vitro. Our data suggest a trophic action of the C-terminal part (ACTH(18–39)) of the corticotrophic molecule. Clear trophic effects were also found for the N-terminal part of the pro-opiomelanocortin molecule N-POC(1–76) (optimum 0·1 nmol/l) and N-POC(51– 62) (optimum 0·1 pmol/l). The latter observations support earlier concepts that this part of the proopiomelanocortin molecule has a stimulatory effect on adrenal DNA synthesis. J. Endocr. (1987) 115, 505–510

STIMULATION OF RABBIT LYMPHOCYTES IN VITRO BY A PROTOZOAN FACTOR

1971 ◽  
Vol 13 (3) ◽  
pp. 457-459
Author(s):  
William H. Beckert ◽  
John Davis ◽  
Sr. Margaret M. Sharkey
Keyword(s):  
Growth Rate ◽  
Growth Medium ◽  
Peripheral Blood ◽  
Peripheral Blood Lymphocytes ◽  
Blood Lymphocytes ◽  
Rabbit Lymphocytes ◽  
Stimulation Of

A substance extracted from the growth medium of Colpidium can cause blastogenesis with subsequent mitosis of rabbit peripheral blood lymphocytes in vitro. This substance, termed a probiotic, is also capable of influencing the growth rate of various species of protozoa.

scholarly journals THE EFFECTS OF ANTIGENS AND OF PHYTOHEMAGGLUTININ ON RABBIT SPLEEN CELL SUSPENSIONS

1966 ◽  
Vol 124 (4) ◽  
pp. 621-634 ◽  
Author(s):  
G. Harris ◽  
R. J. Littleton
Keyword(s):  
Dna Synthesis ◽  
Spleen Cell ◽  
Cell Suspensions ◽  
Red Cells ◽  
Specific Response ◽  
Spleen Cells ◽  
Sheep Red Cells ◽  
Stimulation Of

Phytohemagglutinin (PHA) stimulated the rate of DNA synthesis in rabbit spleen cell suspensions. Unlike antigens, previous immunization to PHA was not necessary and the specific response could not be transferred by macrophages, although lymphocytes primed by incubation in PHA were able to stimulate other spleen cells not directly exposed to PHA. When rabbits were stimulated by in vivo immunization with antigens, spleen cells proliferating in response to antigen were stimulated to divide by in vitro contact with PHA. Using the technique of specific hemolytic plaque formation by individual cells synthesizing γM-antibody to sheep red cells (plaque-forming cells), no evidence was obtained that stimulation of cell division by PHA resulted in specific antibody formation, although the presence of antigen resulted both in stimulation of cell proliferation and the production of plaque-forming cells. The presence of both sheep red cells and PHA in the medium of the same cell suspensions did not enhance the production of plaque-forming cells although there was a summative effect on DNA synthesis.

Gentamicin-induced stimulation of DNA synthesis in rat kidney comparison between in vivo and in vitro models

1984 ◽  
Vol 23 (2) ◽  
pp. 205-213 ◽  
Author(s):  
G.A. Porter ◽  
G. Laurent ◽  
P. Maldague ◽  
P. Tulkens
Keyword(s):  
Dna Synthesis ◽  
Rat Kidney ◽  
In Vitro Models ◽  
Stimulation Of
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