The production of differentiation autoinducing activity by WEHI-3B D+ leukemia cells

We studied the differentiation autoinducing activity in WEHI-3B D+ cell-conditioned medium (WCM). After culturing 10(6)/ml WEHI-3B D+ cells in RPMI-1640 medium without fetal calf serum (FCS) for 4 days, the supernatant was collected. The medium, concentrated 50-fold by YM-5 membrane filtration, was fractionated by gel exclusion on Ultrogel AcA44. We evaluated the effect of each of the four fractions on differentiation in WEHI-3B D+ cells by morphological, functional, and cytochemical criteria after adding the fractions to liquid or soft-agar cultures of 10(3) cells in 1 ml RPMI-1640 medium containing 10% FCS; the experimental cultures contained 10% of the fractions, with a control for each without the fraction. The growth of WEHI-3B D- cells in culture was inhibited by the addition of fraction P only (mol. wt. 10,000-20,000 daltons). In these same cultures, the cells were granulocyte-like, strongly positive for naphthol ASD chloroacetate esterase, and had phagocytic activity. Colonies grown in agar culture with fraction P also exhibited a peripheral halo of loosely dispersed cells around a central aggregate. Fraction P contained neither granulocyte colony-stimulating activity nor burst-promoting activity. These results suggest that fraction P contains differentiation autoinducing factor that is different from granulocyte colony-stimulating factor or interleukin 3.     

Successful replacement of fetal calf serum with human urine for in vitro culture of Leishmania donovani.

Leishmania donovani causes visceral leishmaniasis claiming several thousand lives every year in Indian sub-continent. The etiological agent is grown in cell free media supplemented with fetal calf serum (FCS). Urine from human beings and other mammalian species has also been reported to stimulate growth of Leishmania species No study has been carried out Leishmania donovani. Therefore, we studied the feasibility of culturing Leishmania donovani promastigotes in M199 medium supplemented with 10% human urine and compared the phenotypic and genotypic characters under supplementation with urine vis-a-vis FCS. The growth curve showed no significant difference in the promastigote counts in urine vs. FCS supplementation. The best growth was observed in cultures supplemented with the post-menopausal urine. No difference in antigenic bands and RFLP pattern was seen indicating that no alteration occurred in strain specific characters of the parasites cultured with human urine.     

In vitro development of Haplorchis taichui (Trematoda: Heterophyidae)

Newly excysted metacercariae of Haplorchis taichui were cultured in a candle jar set at 37 degrees C. Both monophasic culture media [0.85% NaCl, RPMI 1640, RPMI 1640+10% fetal calf serum (FCS)] and diphasic culture media [RPMI 1640 + egg yolk agar, RPMI 1640 + 5%, 10% or 15% blood in blood agar (BA), RMPI 1640 + 5%, 10% and 15% FCS with 5% blood in BA] were used in vitro. Parasites survived for only 1 day in 0.85% NaCl without any development. In RPMI 1640 with egg yolk agar and RMPI 1640 + 5%, 10% FCS, the parasite survived for 3-5 days. In contrast, worms survived for 12-14 days in RPMI 1640 with blood agar without any change in result in a different concentration of blood in BA. The ovary and testes were observed after 3 days incubation in this media. Nevertheless, only 1 parasite in RPMI 1640 with 15% blood in BA had vitellaria and eggs at day 6. RPMI 1640 with blood agar can be used as short-term maintenance for the in vitro culture of H. taichui. However, further studies are needed.     

日本血吸虫成虫细胞培养条件的初步研究

本文报道日本血吸虫成虫细胞培养条件的初步研究.结果表明:日本血吸虫的成虫细胞,在合成培养基RPMI-1640和5%的小牛血清、台成培养基TC-199和10%或20%的小牛血清培养液中,在附加常量抗菌素、pH值为7.2—7.4、培养温度为36℃一37℃条件下,其存活时间均可超过150d.另外,成虫细胞在未加抗菌素或附加一定量(常量或两倍于常量)抗菌素的培养液中的存活天数,没有明显差别.     

Growth of infective forms of Trypanosoma (T.) brucei on buffalo lung and Chinese hamster lung tissue culture cells.

Infective cultures of Trypanosoma (T.) brucei (strain 427) have been initiated and maintained on Chinese hamster lung tissue culture cells and buffalo lung tissue culture cells. By changing daily one-third of the RPMI-1640 plus 20% fetal bovine serum medium, the cell numbers can be maintained at 2--4 X 10(6) cells/ml. The cultured trypanosomes on these two tissue culture cell types were infective to mice and morphologically similar to bloodstream slender trypomastigotes in having a subterminal kinetoplast and a surface coat. In addition, they possessed the L-alpha-glycerophosphate oxidase, the predominant steady state terminal oxidase identified in bloodstream trypomastigotes.     

Reproduction of Leishmania (Leishmania ) infantum chagasi in conditioned cell culture growth medium

Leishmanias can be produced by inoculation in conditioned McCoy cell culture growth medium (CGM). Leishmania (Leishmania) infantum chagasi (100 parasites) grown in NNN medium was inoculated in 2.5 mL CGM, kept in plates (24 wells) and its multiplication was observed for five days (120 hours). After day 5, the medium was saturated with the flagellate forms of the parasite (promastigotes). The reproduction of the leishmanias was observed every 24 hours and the number of parasites was calculated by counting the parasites in a drop of 10 microL and photomicrographed. So the number of Leishmanias was adjusted to 1 mL volume. The advantage of the technique by isolation of Leishmania in CGM demonstrated in this study is its low cost and high efficacy even with a small quantity of parasites (10(2) promastigotes) used as inoculum. Additionally, isolation of the leishmania can be obtained together with an increase in their density (180 times) as observed by growth kinetics, within a shorter time. These results justify the use of this low-cost technique for the isolation and investigation of the behavior and multiplication of Leishmania both in vertebrates and invertebrates, besides offering means of obtaining antigens, whether whole antigens (leishmanias) or the soluble antigens produced by the parasites which may be useful for the production of new diagnostic kits.     

Leishmania major: resistance of promastigotes to paromomycin, and susceptibility of amastigotes to paromomycin-methylbenzethonium chloride ointment.

Cutaneous lesions caused by Leishmania major in BALB/c mice were cured completely when treated topically with an ointment comprising 15% paromomycin sulphate and 1-2% methylbenzethonium chloride ointment in soft white paraffin twice daily for 10 days. No parasites were detected in tissue smears or in cultures from treated cutaneous lesions. Re-developing lesions, considered to be resulting from the migration of parasites from internal organs, showed almost the same response to topical treatment. Promastigotes of the virulent clone 121 of L. major LRC-L137 which were exposed to 100 micrograms ml-1 of paromomycin in RPMI medium at 28 degrees C developed resistance to the drug over 10 passages of exposure. Enzyme analysis of susceptible and resistant promastigotes of this clone showed no differences with regard to their profiles based on 11 enzymes.     

Insulin-like growth factor secretion by human B-lymphocytes: a comparison of cells from normal and pygmy subjects

Freshly isolated human B-lymphocytes from eight subjects and Epstein-Barr virus-transformed human B-lymphocytes from seven subjects were examined for their capacity to secrete insulin-like growth factor-I (IGF-I) and IGF-II and for their capacity to respond to human GH. Similar studies were conducted with Epstein-Barr virus-transformed lymphocytes collected from six African pygmies. When transformed B-lymphocytes from normal stature subjects were cultured for 3 weeks in RPMI-1640 medium (6 x 10(3) cells/75-cm2 flask at seeding), significant amounts of IGF-I, but no IGF-II, were produced. GH (150 ng/mL) significantly increased for control cells the amount of IGF-I produced at each sampling interval compared to that by unstimulated cultures (P less than 0.05 at 1 week; P = 0.005 at 3 weeks). At 3 weeks, cell counts of cultures compared were 4.13 +/- 0.39 X 10(6)/mL for unstimulated cells and 4.23 +/- 0.87 X 10(6)/mL for GH-stimulated cells. IGF-I production at this time interval by unstimulated cells was 2.8 +/- 2.3 ng/mL, and that by GH-stimulated cells was 12.3 +/- 2.5 ng/mL (P = 0.005). Cell multiplication rates of control cultures were increased in 1 week by GH stimulation [GH stimulated, [16.7 +/- 22.0 X 10(4) cells, unstimulated, 5.73 +/- 4.1 X 10(4) cells; (mean +/- SD); n = 14; P less than 0.01]. Similar results occurred with GH studied at a lower concentration of 10 ng/mL for 3 weeks. Freshly isolated B-lymphocytes did not secrete IGF-I and II after 5 days of culture with GH. Cultures established from cells derived from pygmies produced significantly less IGF-I (4.24 +/- 2.62 ng/mL) when stimulated with 150 ng/mL GH than cultures of cells from normal stature subjects (12.3 +/- 2.5 ng/mL; 0.005 less than P less than 0.01). The cultures compared had a similar cell density. A similar significant difference in IGF-I secretion occurred between cultures of pygmy and control cells stimulated with 10 ng/mL GH. These data are consistent with previous in vivo studies in which pygmies failed to increase IGF-I and exhibit metabolic responses to exogenous GH.     

A simplified method for cryopreservation of Plasmodium falciparum from continuous in vitro cultures

Human erythrocytes parasitized with Plasmodium falciparum, obtained from in vitro continuous cultures and stored at -185 degrees C and at -70 degrees C for several months, were successfully recovered. Ten per cent glycerol or 10% dimethyl sulphoxide in growth medium RPMI 1640 were used and found equally effective as cryopreservatives. This simplified method does not require centrifugation or special media before storage or after recovery of the parasites. The viability of the parasites is monitored in vitro by initiating new continuous cultures.     

Leishmania disease development depends on the presence of apoptotic promastigotes in the virulent inoculum

The obligate intracellular pathogen Leishmania major survives and multiplies in professional phagocytes. The evasion strategy to circumvent killing by host phagocytes and establish a productive infection is poorly understood. Here we report that the virulent inoculum of Leishmania promastigotes contains a high ratio of annexin A5-binding apoptotic parasites. This subpopulation of parasites is characterized by a round body shape, a swollen kinetoplast, nuclear condensation, and a lack of multiplication and represents dying or already dead parasites. After depleting the apoptotic parasites from a virulent population, Leishmania do not survive in phagocytes in vitro and lose their disease-inducing ability in vivo. TGF-beta induced by apoptotic parasites is likely to mediate the silencing of phagocytes and lead to survival of infectious Leishmania populations. The data demonstrate that apoptotic promastigotes, in an altruistic way, enable the intracellular survival of the viable parasites.     

Development of metacyclic Leishmania promastigotes is associated with the increasing expression of GP65, the major surface antigen

Using immunofluorescence techniques and flow microfluorometry analysis, we have demonstrated that the binding of a monoclonal antibody (VD5/25) produced against GP65, the major surface antigen of Leishmania braziliensis, increased on the surface of stationary-phase promastigotes from all the New World Leishmania species causing mucocutaneous or cutaneous disease as compared with the log-phase parasites. In addition, a sequential development of Leishmania amazonensis promastigotes from a non-infective to an infective stage was demonstrated. Indeed, promastigotes in the stationary phase (days 6-7) were found to be far more infective than those in the logarithmic phase of growth (day 3) both in vitro for mouse peritoneal macrophages and in vivo for BALB/c mice. The intracellular survival and multiplication of L. amazonensis were significantly inhibited when infective promastigotes were treated with the VD5/25 monoclonal antibody. The increasing expression of GP65 on the promastigote surface may thus contribute to Leishmania infectivity. This seems to represent a characteristic mechanism applicable to all New World Leishmania species studied.     

Pathophysiology of experimental leishmaniasis: the role of parasite physiology in the development of metastatic disease

This paper addresses the issue of how physiological properties of Leishmania determine the pattern of development of disseminated leishmaniasis in the mammalian host. It presents direct experimental evidence from in vivo studies that species of Leishmania differ in their capacity to multiply in cutaneous and visceral sites which results in differences in the pattern and rate of development of leishmaniasis. It was found that Leishmania mexicana amazonensis begins to multiply in the cutaneous site of inoculation within 7 days. Parasites, detected in the liver and spleen at 4 weeks, increased 100-fold during the next 4 months. However, the slow multiplication of L. mexicana amazonensis in the liver and spleen was more apparent than real. Parasites implanted in those organs of athymic nude mice by an intravenous injection were rapidly eliminated with a half-time of 16 hr. Thus, the parasites found in small numbers in the liver during the development of disseminated cutaneous disease in mice are most likely those which have been recently removed from the blood. Those few parasites that are not removed from the blood can establish metastatic foci in distant cutaneous sites, and replicate progressively once there.     

Preliminary study towards a novel experimental model to study localized cutaneous leishmaniasis caused by Leishmania (Leishmania) mexicana

There is not an experimental model of localized cutaneous leishmaniasis (LCL) caused by Leishmania (Leishmania) mexicana. The aim of the present study was to characterize the clinical and histological features of Peromyscus yucatanicus experimentally infected with L. (L.) mexicana. A total of 54 P. yucatanicus (groups of 18) were inoculated with 1x10(6) promastigotes of L. (L.) mexicana in the base of the tail. They were euthanized at three and six months post experimental infection. The control group was inoculated with RPMI-1640. The predominant clinical sign observed was a single ulcerated lesion in 27.77% (5/18) and in 11.11% (2/18) P. yucatanicus at three and six months respectively. The histological pattern described as chronic granulomatous inflammation with or without necrosis was found in 7/7 (100%) biopsies of euthanized P. yucatanicus at three (n = 5) and six (n = 2) months, respectively. These results resembled clinical and histological features caused by L. (L.) mexicana in humans, and support the possibility to employ P. yucatanicus as a novel experimental model to study LCL caused by this parasite.     

Effect of human urine on cell cycle and infectivity of Leismania species promastigotes in vitro

In vitro cultivation of Leishmania parasites plays an important role in diagnosis and treatment of leishmaniasis and in vaccine and drug development studies. Conversely, long-term cultivation of Leishmania parasites usually results in decreased infectivity potential. Some studies reported a stimulatory effect of human urine in Leishmania promastigotes. However, there is no information about the effects of urine within culture on the infectivity of Leishmania parasites. Analysis of the effect of urine have showed that proliferation indexes were significantly increased in culture medium supplemented with human urine (L. tropica = 38.17 ± 5.12, L. donovani = 34.74 ± 5.6, L. major = 34.22 ± 4.66, and L. infantum 35.88 ± 6.40) than in controls. Infection indexes were 13 ± 1.7 for L. tropica, 55 ± 2.2 for L. infantum, 41 ± 3.14 for L. donovani, and 49 ± 3.26 for L. major. Our results showed that human urine increased the infectivity and proliferation of Leishmania parasites.     

班氏丝虫和马来丝虫感染期幼虫体外培养的进一步研究

在4种培养系统中,马来丝虫Ⅲ期幼虫在改良RPMI1640、20%小牛血清和人胚肾细胞系为饲养层的培养系统中生长发育良好,可以从Ⅲ期幼虫蜕皮2次发育到童虫,最长存活时间为54d。在单纯改良RPMI1640、TC199和20％小牛血清中培养,从Ⅲ期幼虫发育到童虫的最长存活时间为42d。班氏丝虫Ⅲ期幼虫在上述2种培养系统中,分别存活57和36d,从Ⅲ期幼虫蜕皮进入Ⅳ期幼虫和童虫。对马来丝虫幼虫体外培养蜕皮时间、虫体大小与沙鼠体内发育情况进行了比较。     

Serum-free medium enhances growth and differentiation of cultured pig granulosa cells

We have developed new serum-free culture techniques for swine granulosa cells from immature (1-3 mm) follicles. These methods have allowed more detailed examination of factors regulating both replication and cytodifferentiation of these cells. For optimal replication, collagen-coated culture dishes and a highly supplemented nutrient medium (a 1:1 mixture of Dulbecco's modified Eagle's medium and Ham's F-10), containing 5 micrograms/ml transferrin, 300 mU/ml insulin, 40 ng/ml hydrocortisone, 4 mg/ml BSA, and 2.5% (vol/vol) of a platelet extract (PE) was found to be essential. Cultures maintained in this serum-free complete medium (SFCM) grew to confluence and contained as many or more cells than replicate cultures maintained in 10% fetal calf serum (10% FCS) (e.g. SFCM: 1.89 +/- 0.17; 10% FCS: 1.12 +/- 0.02 cells per well X 10(-5) on day 6). In the absence of albumin, PE, or without collagen coating, the cell numbers were, respectively 4.5%, 9.8%, and 5.0% of that observed with complete SFCM. The mitogenic effect of the PE was due to heat-labile as well as heat-stable components and could not be replaced by platelet-derived growth factor. To evaluate cytodifferentiation, cells grown in SFCM were compared with those grown in 10% FCS with regard to progesterone secretion and FSH responsiveness. Basal progesterone levels were higher in SFCM at all stages in culture. FSH stimulated progesterone secretion in both 10% FCS and SFCM. However, FSH responsiveness was diminished after 4 days with 10% FCS, whereas cells in SFCM remained responsive for 10 days. Thus, this system seems to be highly suitable for the study of the regulation of growth and differentiation of granulosa cells.     

Long-term culture of canine bone marrow cells

Conditions that allow the growth of canine marrow cells in long-term marrow culture are described. The quality of the culture conditions was evaluated based on the weekly number of granulocyte-macrophage colony-forming units (CFU-GM) in the nonadherent cell fraction. Using this parameter, the highest number of CFU-GM was obtained when marrow cells were incubated at 37 degrees C in RPMI-1640 or McCoy's 5A medium supplemented with 20% prescreened horse serum without addition of hydrocortisone. CFU-GM colonies could be regularly grown out of the nonadherent cell fraction for 20-31 weeks, after recharging the cultures with 1.5 X 10(7) mononuclear autologous marrow cells 1 week after establishing the stromal cell layer.     

Effect of tissue culture media on multiplication of Plasmodium falciparum in vitro.

To date RPMI-1640 has been the best medium for cultivation of Plasmodium falciparum in vitro. In addition to this medium, several alternative media, essentially the ones used in animal and plant tissue culture, were employed for the cultivation of P. falciparum. Only the media rich in glucose content, viz. Nitsch medium and White's medium S-3, supported the parasite multiplication.     

Determinants of cardiomyocyte development in long-term primary culture

The influence of cell attachment to substrates and of medium composition on development of cardiomyocytes from adult rats in cultures up to 9 days old was investigated. Cardiomyocytes prevented from attaching to a culture substratum deteriorated within 3 days in medium 199 (M199) with or without fetal calf serum (FCS). Rapid attachment during the first 4 h after plating could be attained equally well on FCS or laminin coated surfaces. In M199 without FCS, attached cardiomyocytes on FCS coated dishes were able to retain their overall elongated morphology, but the number of cells remaining attached constantly decreased during the first 9 days in serum free culture. Attached on laminin the rate of loss from serum free cultures was lower. In the presence of 20% FCS, attached cardiomyocytes spread extensively after day 3, both on FCS and on laminin coated dishes. In serum containing media many cells pass through a spherical intermediate state before spreading extensively. Almost all cardiomyocytes cultured with 20% FCS on untreated tissue culture plastic gradually become spherical before attaching. With 20% FCS in culture media, the number of cells remaining in culture after 9 days was similar whether cells were rapidly attached to FCS treated or laminin coated substrata, or were plated on culture plastic, i.e., 52, 63, and 45% of the maximal number attached on day 1. By day 9 in all three culture types cells were spread and were beating spontaneously. These results indicate that adult cardiomyocytes do not establish in a stable morphological state in long-term cultures, in other than a surface attached spread cell form. For this stability the presence of yet unidentified components of fetal calf serum is required.     

Apolipoprotein B synthesis in humans: liver synthesizes only apolipoprotein B-100

Apolipoprotein (apo) B-100 and B-48 are prominent apolipoproteins in VLDL, IDL, and chylomicrons. Organ cultures of normal adult human liver were established to ascertain the form of apo B synthesized by hepatocytes in humans. Human liver was minced and incubated in 15 mL methionine-free RPMI-1640 medium with 10% dialyzed fetal calf serum plus 250 microCi 35S-methionine for eight hours at 37 degrees C. Lipoproteins secreted by the liver were isolated by ultracentrifugation and the content of newly synthesized apo B determined by quantitation of radioactivity in the apoB-100 and apoB-48 bands after separation by 3% NaDodSO4 gel electrophoresis. In the eight-hour period, 2.5% to 3.2% of added 35S-methionine was secreted in TCA-precipitable protein of which 0.34% was apo B. Ninety-nine percent of the apo B in VLDL, IDL, and LDL was in the apo B-100 electrophoretic band. No significant radioactivity was detected in the apo B-48 electrophoretic band. Eighty-nine percent of the total radioactivity of apo B-100 was in VLDL with 3% and 8% in IDL and LDL, respectively. These results establish that adult human liver in organ culture synthesizes apo B-100 but not apo B-48.