STREET. 1973. Control of growth and cell division in plant cell suspension cultures. Can. J. Bot. 51: 1807-1823. In batch suspension cult~lres variation occurs in the growth and metabolism of the cells both in space and with time. Viable cell pop~~lations of sycamore (Acer pselrdol~lata~~lrs L.), showing greatly reduced aggregation and more uniform mor hology, can be obtained by incorporating enzymes into the culture medium. Such techniques cornbinefwith single cell cloning will take us closer to uniformity within the culture. The problem set by the continuous change in the metabolic activities of the cells with time (during the progress of the growth cycle of batch cultures) has been overcome by the use of low-density synchronous cultures and by the establishment of steady states of growth in chemostat cultures. Experimental work with sycalnore cell suspensions is described showing (1) the achievement of prolonged cell division synchrony in 4-liter suspension cultures and (2) the conformity of the growth kinetics of cells in chemostat culture to the mathematical model developed by Monod (1950, Ann. Inst. Pasteur (Paris), 79: 39&410) for microorganisnls. KING, P. J., K. J. MANSFIELD et H. E. STREET. 1973. Control of growth and cell division in plant cell suspensioil cultures. Can. J. Bot. 51: 1807-1823. Lors u'on cultive des suspensions de cellules en lot, des variations se produisent dans la croissance et le mtta%olisme des cellules en fonction de la situation spatiale et du temps. Des populations de cellules viables de sycomore (Acer pse~l~iaplam~lus L.) montrant une tendance B I'agrCgation considCrablement rCduite et une morphologie plus uniforme, peuvent Ctre obtenues en incorporant des enzymes dans le milieu de culture. De telles techniques, associkes B celles du clBnage de cellules isolCes, nous permettrons d'obtenir de plus en plus d'uniformitC dans les cultures. Le probEme, dCcoulant du changement constant des activitCs mCtaboliques des cellules en fonction du temps, (pendant le dkroulement du cycle de croissance dans les cultures en lot), a CtC surmontk par I'utilisation de cultures synchrones i faible densit6 cellulaire, et par le maintien d'un taux de croissance constant en culture en chemostat. Le travail expCrimental rCalisC sur les suspensions de cellules de sycomore est decrit; il montre qu'une synchronic prolongke des divisions cellulaires a Ct C obtenue sur des cultures de 4 litres de suspensions de cellules, et que la cinitique de la croissance des cellules cultivCes en chernostat obeit au modkle mathCmatique dCcouvert par Monod (1950, Ann. Inst. Pasteur (Paris), 79: 39@410), pour les microorganismes. Introduction(as growth in batch culture proceeds). Efforts This paper will examine two propos~t~ons ill have therefore been directed towards the dethe light of currellt research achievemellt from velopment of free-cell cultures and to the estabour own other laboratories. These proposi-lishment of cultural conditions leading to steady tions are (i) that plant cell suspension cultures states of grow...
BackgroundDendritic cells (DCs) are antigen presenting cells capable of inducing specific immune responses against microbial infections, transplant antigens, or tumors. Interestingly, microenvironment conditions such as those present in tumor settings might induce a DC phenotype that is poorly immunogenic and with the capability of promoting angiogenesis. We hypothesize that this plasticity may be caused not only by the action of specific cytokines or growth factors but also by the properties of the surfaces with which they interact, such as extracellular matrix (ECM) components.ResultsHerewith we studied the effect of different surfaces and soluble factors on the biology of DCs. To accomplish this, we cultured murine myeloid(m) DCs on surfaces coated with fibronectin, collagen I, gelatin, and Matrigel using poly-D-lysine and polystyrene as non-biological surfaces. Further, we cultured these cells in the presence of regular DC medium (RPMI 10% FBS) or commercially available endothelial medium (EGM-2). We determined that mDCs could be kept in culture up to 3 weeks in these conditions, but only in the presence of GM-CSF. We were able to determine that long-term DC cultures produce an array of angiogenic factors, and that some of these cultures still retain the capability to induce T cell responses.ConclusionsAltogether these data indicate that in order to design DC-based vaccines or treatments focused on changing the phenotype of DCs associated with diseases such as cancer or atherosclerosis, it becomes necessary to fully investigate the microenvironment in which these cells are present or will be delivered.
Carbon dioxide (optimum concentration c. 1.0%) is essential to the initiation of the growth in suspension culture or on agar plates of cultured sycamore cells. By effective flushing of the cultures with CO -free air it is possible to demonstrate this requirement with initial cell densities up to 50 × 10 cells ml . This growth-promoting activity of carbon dioxide is not related to any effect it may have on the pH of the culture medium. The cells fix applied carbon dioxide into organic and amino acids but attempts to replace the carbon dioxide requirement by non-toxic levels of organic or amino acids have not been successful.
Dendritic cells (DCs) are antigen presenting cells capable of inducing specific immune responses against microbial infections, transplant antigens, or tumors. DCs have been shown to possess a high plasticity showing different phenotypes in response to their microenvironment. For example, tumor-associated DCs can acquire an angiogenic phenotype thus promoting tumor growth. Further, DCs cultured in vitro under different conditions are able to upregulate the expression of endothelial markers and to express angiogenic factors. Indeed, it has been shown that soluble factors such as VEGF of PGE-2, that are present in the microenvironment of several tumors, affect the biology of these cells. We hypothesize that in addition to soluble factors the adhesion to different substrates will also define the phenotype and function of DCs. Herewith we demonstrate that murine myeloid(m) DCs upregulate endothelial markers such as VE-Cadherin, and to a lesser extent TIE-2, and decrease their immune capabilities when cultured on solid surfaces as compared with the same cells cultured on ultra-low binding (ULB) surfaces. On the other hand, the expression of angiogenic molecules at the level of RNA was not different among these cultures. In order to further investigate this phenomenon we used the murine ID8 model of ovarian cancer which can generate solid tumors when cancer cells are injected subcutaneously or a malignant ascites when they are injected intraperitoneally. This model gave us the unique opportunity to investigate DCs in suspension or attached to solid surfaces under the influence of the same tumor cells. We were able to determine that DCs present in solid tumors showed higher levels of expression of endothelial markers and angiogenic molecules but were not able to respond to inflammatory stimuli at the same extent as DCs recovered from ascites. Moreover, mDCs cultured on ULB surfaces in the presence of tumor factors do not expressed endothelial markers. Taking into account all these data we consider that tumor factors might be responsible for inducing angiogenic properties in DCs, but that in some settings the expression of endothelial markers such as VE-Cadherin and TIE-2 might be a function of attachment to solid surfaces and independent of the angiogenic properties of these cells.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.