Normal and certain leukaemic B cells express IL-2 receptors without in vitro activation.

IL-2 receptor expression by B cells has previously been considered to be confined to activated normal B cells and, among the B cell leukaemias, to the hairy cells (HC) of hairy-cell leukaemia. In the present paper, using alpha-Tac monoclonal antibodies in a highly sensitive indirect rosette method, we show that both normal and certain leukaemic B cells other than HC express IL-2 receptors. The density of these receptors is low since they were not detectable by indirect immunofluorescence. Various controls excluded non-specific-reagent or exogenous receptor binding and blocking studies with recombinant IL-2 confirmed the presence of the IL-2 receptors. The significance of the findings is discussed and it is suggested that B cell IL-2 receptor expression without in-vitro activation may be a function of B cell maturity.     

Normal human glomerular cells in culture.

Reproducible patterns of cell outgrowth have been observed from isolated normal adult, human glomeruli grown in tissue culture. Three morphologically distinct cell populations designated Types I, II, and III have been observed in culture from 15 normal human kidneys. Assessment of the morphology and behaviour of these cells has been made by phase contrast, time-lapse cinemicroscopic, transmission and scanning electron microscopic examination. The phagocytic capacity of these cells has been determined. The Type I cell appears in culture by migration from the capillary loops, its branched cytoplasm and ultrastructural features confirming its origin as a visceral epithelial cell. In keeping with the highly specialised nature of this cell, division was rare, movement was not observed, and differentiation was progressively lost in culture. The Type II cell was mobile and capable of active division. Ultrastructural features were those of mesangial cells. The Type III cell which was seen only rarely, had the features of a macrophage. Endothelial outgrowth was not observed.     

Mucosal type mast cells express complement receptor type 2 (CD21)

Fragments of complement component C3 generated upon activation of the cascade play an important role in the induction and regulation of immune responses. Receptors interacting with various fragments of this versatile complement protein are expressed on a wide variety of cell types, including lymphocytes, macrophages, dendritic cells, follicular dendritic cells, granulocytes, erythrocytes and consequently, C3-products may influence several biological functions at different sites of the body, where complement activation occurs. Regarding the expression of various C3-receptors on mast cells, mainly rodent serosal type mastocytes have been investigated so far. It has been known for a long time that C3a triggers the release of mediators of immediate type hypersensitivity via binding to serosal-type cells. Complement receptor type 1 (CR1/CD35) and type 2 (CR2/CD21) interacting with the larger activation products, such as C3b and C3d, have so far been shown on serosal type mast cells only. In this study, the expression of CR1/2 on mucosal type mast cells is demonstrated. Using mouse CR1/2 specific single chain antibodies and the natural ligand C3d in cytofluorimetric measurements, we show that the rat mucosal mast cell line RBL-2H3 and mouse bone marrow-derived mast cells (BMMC) express CD21. RT-PCR experiments carried out with mouse CR1 and CR2 specific primers show CD21, but not CD35 specific products in BMMC. It is also demonstrated that, in contrast to serosal type mast cells, mucosal mastocytes do not express CD19. In an attempt to reveal the possible function of CR2 on mucosal type mast cells, the effect of receptor-clustering was tested regarding degranulation, Ca-response and IL-6 production, but no CR2-mediated change was detected in any of these processes.     

An appropriate in vitro culture condition for the induction of human TCR gamma delta + cells by heat-killed bacteria.

TCR gamma delta + cells proliferated when MNC were stimulated with various heat-killed bacteria. We investigated here the culture conditions for their maximum proliferation. MNC were cultured for 6 days with Streptococcus pyogenes, and for 3 days with T cell mitogens, PHA and anti-CD3 mAb, in medium supplemented with various concentrations (0.05-50%) of human sera. TCR gamma delta + and TCR gamma delta- CD2+3- double negative cells induced by Str. pyogenes required high concentrations of sera (greater than 6%) for their proliferation. Moreover, increased sera (up to 50%) greatly augmented their proliferation. On the other hand, TCR alpha beta + cell proliferation induced by T cell mitogens was supported by a small concentration (even 0.1%) of the sera, and the addition of high concentrations of sera (greater than 6%) somewhat suppressed responses. Similar serum requirement patterns were evident for the induction of cytotoxic cells. These results clearly demonstrated the existence of an appropriate culture condition for the proliferation of TCR gamma delta + cells induced in vitro.     

Normal human fibroblasts express pattern recognition receptors for fungal (1-->3)-beta-D-glucans

Fungal cell wall glucans nonspecifically stimulate various aspects of innate immunity. Glucans are thought to mediate their effects via interaction with membrane receptors on macrophages, neutrophils, and NK cells. There have been no reports of glucan receptors on nonimmune cells. We investigated the binding of a water-soluble glucan in primary cultures of normal human dermal fibroblasts (NHDF). Membranes from NHDF exhibited saturable binding with an apparent dissociation constant (K(D)) of 8.9 +/- 1.9 microg of protein per ml and a maximum binding of 100 +/- 8 resonance units. Competition studies demonstrated the presence of at least two glucan binding sites on NHDF. Glucan phosphate competed for all binding sites, with a K(D) of 5.6 microM (95% confidence interval [CI], 3.0 to 11 microM), while laminarin competed for 69% +/- 6% of binding sites, with a K(D) of 3.7 microM (95% CI, 1.9 to 7.3 microM). Glucan (1 microg/ml) stimulated fibroblast NF-kappaB nuclear binding activity and interleukin 6 (IL-6) gene expression in a time-dependent manner. NF-kappaB was activated at 4, 8, and 12 h, while IL-6 mRNA levels were increased by 48% at 8 h. This is the first report of pattern recognition receptors for glucan on human fibroblasts and the first demonstration of glucan binding sites on cells other than leukocytes. It also provides the first evidence that glucans can directly modulate the functional activity of NHDF. These results provide new insights into the mechanisms by which the host recognizes and responds to fungal (1-->3)-beta-D-glucans and suggests that the response to glucans may not be confined to cells of the immune system.     

Mesenchymal stem cells spontaneously express neural proteins in culture and are neurogenic after transplantation

Reports of neural transdifferentiation of mesenchymal stem cells (MSCs) suggest the possibility that these cells may serve as a source for stem cell-based regenerative medicine to treat neurological disorders. However, some recent studies controvert previous reports of MSC neurogenecity. In the current study, we evaluate the neural differentiation potential of mouse bone marrow-derived MSCs. Surprisingly, we found that MSCs spontaneously express certain neuronal phenotype markers in culture, in the absence of specialized induction reagents. A previously published neural induction protocol that elevates cytoplasmic cyclic AMP does not upregulate neuron-specific protein expression significantly in MSCs but does significantly increase expression of the astrocyte-specific glial fibrillary acidic protein. Finally, when grafted into the lateral ventricles of neonatal mouse brain, MSCs migrate extensively and differentiate into olfactory bulb granule cells and periventricular astrocytes, without evidence of cell fusion. These results indicate that MSCs may be "primed" toward a neural fate by the constitutive expression of neuronal antigens and that they seem to respond with an appropriate neural pattern of differentiation when exposed to the environment of the developing brain.     

Regulation of a murine macrophage haemagglutinin (sheep erythrocyte receptor) by a species-restricted serum factor.

The mechanisms which generate heterogeneity amongst resident tissue macrophages (M phi) are poorly understood. In a previous study we described a novel mouse M phi haemagglutinin, which binds unopsonized sheep erythrocytes. This sheep erythrocyte receptor (SER) is expressed at high levels on stromal M phi from bone marrow and lymph nodes, but at low levels on M phi from serous cavities and broncho-alveolar spaces. In this paper we demonstrate that a species-restricted factor in mouse serum is required in vitro for optimal maintenance of SER on resident bone marrow M phi and for its induction on M phi populations which normally lack this receptor. Using thioglycollate-elicited peritoneal M phi, induction of SER by mouse serum was dose-dependent, reached maximal levels by 3-4 days, required the continuous presence of mouse serum, and was fully reversible. Re-expression following trypsinization was inhibited by cycloheximide, showing that protein synthesis by M phi was necessary. Using a quantitative microtitre plate assay to measure levels of the inducing activity (SER-IA) in different samples, it was found to be heat-labile, non-dialysable, precipitable by polyethylene glycol and inactivated at pH 4 but not at pH 9.6. On gel filtration of mouse serum, a single major peak of activity was obtained with an apparent MW of around 70,000. SER-IA appears to be unrelated to a variety of factors and cytokines which affect M phi function, including colony-stimulating factor-1 (CSF-1). The possible role of SER-IA in regulating the differential expression of SER in vivo is discussed.     

人原生殖细胞的分离与培养

目的:探讨人原生殖细胞(PGC)的分离取材时机与体外培养方法,为人类胚胎生殖细胞(EG)的建系研究奠定基础。方法:取不同孕龄的人胚,分离人PGC,在不同培养体系中,观察其增殖与分化情况。结果:孕8、9周较孕7周人胚用酶机械法分离PGC后,原代克隆形成率高,以小鼠胚胎成纤维细胞或STO细胞作为饲养层,并且在培养液中加入hLIF、hbFGF\,hSCF,能较好地维持人PGC的增殖并保持未分化。结论:孕8、9周龄人胚为分离PGC的适宜材料,酶机械法分离PGC简单有效,饲养层细胞与生长因子为人PGC细胞体外培养所必需。     

Luteinized human granulosa cells are associated with endogenous basement membrane-like components in culture

Human granulosa cells (GC), prepared from follicular aspirates using a non-enzymic method, were maintained in culture on chamber slides in a defined medium without additional attachment factors or extracellular matrix (ECM). In this system, GC clustered to a limited extent and attached only loosely to the substratum necessitating medium replacement through repeated partial changes to avoid cell loss. Using this new culture system, cell size and progesterone production per cell increased, consistent with continuing luteinization. These processes were associated with maintenance and deposition of endogenous ECM components. Thus, pericellular heparan sulphate proteoglycan (HSPG) was clearly visible by immunocytochemistry around the luteinized GC after culture. Also progressive accumulation of laminin (particularly alpha(2)-, beta(1)- and gamma(1)-subunits) during culture was shown by Western blotting of GC extracts. Small patches of collagen IV, shown to be already present between freshly prepared GC, were maintained in culture. A clear effect of gonadotrophin on the maintenance of progesterone production in culture was paralleled by an apparent increased pericellular deposition of HSPG. To conclude, luteinization and maintenance of the GC-derived layer of the corpus luteum is likely to involve deposition and conservation of pericellular ECM components.     

Derivation of human embryonic stem cells from day-8 blastocysts recovered after three-step in vitro culture

Human embryonic stem cells (hESCs) have been derived from the inner cell mass (ICM) of day 5-7 blastocysts and hold great promise for research into human developmental biology and the development of cell therapies for the treatment of human diseases. We report here that our novel three-step culture conditions successfully support the development of day-8 human blastocysts, which possess significantly (p <.01) more ICM cells than day-6 blastocysts. Plating of ICMs isolated from day-8 blastocysts resulted in the formation of a colony with hESC morphology from which a new hESC line (hES-NCL1) was derived. Our stem cell line is characterized by the expression of specific cell surface and gene markers: GTCM-2, TG343, TRA1-60, SSEA-4, alkaline phosphatase, OCT-4, NANOG, and REX-1. Cytogenetic analysis of the hESCs revealed that hES-NCL1 line has a normal female (46, XX) karyotype. The pluripotency of the cell line was confirmed by the formation of teratomas after injection into severely combined immunodeficient mice and spontaneous differentiation under in vitro conditions.     

HMC-1 human mast cells synthesize neurotensin (NT) precursor, secrete bioactive NT-like peptide(s) and express NT receptor NTS1

Objective and design  

To determine if mast cells synthesize the inflammatory peptide, neurotensin (NT), secrete immunoreactive and bioactive NT, and express the NT receptor NTS1.     

不同培养基对人脐静脉内皮细胞体外培养效果的影响

目的研究不同培养基对人脐静脉内皮细胞体外培养生长的影响,探讨内皮细胞的最佳体外扩增培养条件。方法取健康产妇分娩后脐带,用胶原酶Ⅰ消化后得脐静脉内皮细胞,进行原代培养,并用免疫荧光染色的方法对细胞进行鉴定,传代培养时则分别采用RPMI-1640培养基和EGM-2培养基,倒置显微镜观察两种培养条件下细胞的生长状态,同时利用流式细胞仪检测其生长周期,对比培养效果。结果 EGM-2组内皮细胞生长良好,2d后贴壁生长的细胞可达90%。EGM-2组S期细胞比例为（29.07±1.48）%,RPMI-1640培养基组S期细胞为（17.58±3.49）%,二者比较差异有统计学意义（P〈0.01）。结论 EGM-2培养基更适合人脐静脉内皮细胞的体外传代扩增培养。     

Characterization of the human erythrocyte complement receptor CR1 (C3b receptor) by epitope mapping

Monoclonal antibodies and an anti-idiotypic serum against human complement receptor CR1 (C3b receptor, immune adherence receptor) were used to identify CR1 and some of its proteolytic fragments by an immunoblotting technique. The anti-idiotypic serum had a specificity for the C3b-binding site, as could be shown by its cross-reactivity with complement factor H. The monoclonal antibodies GARP-4 and GARP-37 were specific for epitopes located nearby the ligand-binding site, because they blocked the immune adherence reaction. For the immunoblotting technique, it was essential to use non-reducing conditions, since reduction of CR1 destroyed the epitopes. Therefore, mainly large (disulphide-linked) fragments of CR1 were obtained. A chymotryptic fragment of Mr 56,000 identified by GARP-4, was the smallest cleavage product to be associated with the C3b-binding domain. Different proteases gave CR1 degradation products of similar Mr, indicating the presence of distinct domains, three of which had a Mr approximately 38,000. A schematic model of CR1 substructure was deduced from the epitope mapping data.     

Human B cells express the orphan chemokine receptor CRAM-A/B in a maturation-stage-dependent and CCL5-modulated manner

Chemokines orchestrate the organization of leucocyte recruitment during inflammation and homeostasis. Despite growing knowledge of chemokine receptors, some orphan chemokine receptors are still not characterized. The gene CCRL2 encodes such a receptor that exists in two splice variants, CRAM-A and CRAM-B. Here, we report that CRAM is expressed by human peripheral blood and bone marrow B cells, and by different B-cell lines dependent on the B-cell maturation stage. Intriguingly, CRAM surface expression on the pre-B-cell lines Nalm6 and G2 is specifically upregulated in response to the inflammatory chemokine CCL5 (RANTES), a chemokine that is well known to play an important role in modulating immune responses. Although Nalm6 cells do not express any of the known CCL5 binding receptors, extracellular signal-regulated kinases 1 and 2 (ERK1/2) are phosphorylated upon CCL5 stimulation, suggesting a direct effect of CCL5 through the CRAM receptor. However, no calcium mobilization or migratory responses upon CCL5 stimulation are induced in B-cell lines or in transfected cells. Also, ERK1/2 phosphorylation cannot be inhibited by pertussis toxin, suggesting that CRAM does not couple to Gi proteins. Our results describe the expression of a novel, non-classical chemokine receptor on B cells that is potentially involved in immunomodulatory functions together with CCL5.     

In vitro culture of human thymic epithelial cells in serum-free media

Epithelial cells from human thymus were cultured in vitro at various serum concentrations and under defined serum-free conditions. A total of 238 cultures from 46 thymuses (MG and normal) were analyzed. Cells from fresh thymic tissue were explanted either as fragments or single cells after enzyme treatment. Serum-free as well as fetal calf serum (FCS) containing media based on Dulbecco's minimal essential medium and Ham's F-12 (DMEM/F-12) were found to be superior to MCDB 151 based serum-free media combinations, for the selective growth of thymic epithelial cells. In contrast, cultures based on RPMI 1640 medium supplemented with 1% FCS or more showed less epithelial cell selectivity and also supplement Ultroser G gave less fibroblast contamination. In serum-free media containing less than 0.1 mM ionic Ca, the cells had a smaller surface area and appeared more angular and also contained less keratin as compared to culture media with higher calcium contents. The development of serum-free conditions for in vitro growth of human thymic epithelial cells free of fibroblast contamination will facilitate studies of growth and maturation of the epithelial cells as well as investigations of their possible role in the development of myasthenia gravis.     

人胚胎生殖干细胞的分离和体外培养

目的：体外培养人胚胎生殖干细胞(EG),在不添加细胞因子的培养条件下,观察细胞生长情况。方法：取5～10周人胚胎的生殖腺嵴和肠背系膜,进行组织块培养,采用组织化学及免疫细胞化学技术对培养的细胞进行鉴定。结果：培养4d后,在成纤维细胞的上面出现EG细胞集落;培养2周后,显示细胞呈圆形,胞质染成深蓝色;细胞染色体均为正常的二倍体核型;碱性磷酸酶活性强阳性;并检测到SSEA-1。结论：体外培养人胚胎生殖腺嵴,利用源于自身胚胎组织的成纤维细胞作为饲养层,可观察到EG细胞集落的形成;培养的细胞初步鉴定为人胚胎干细胞。     

人眼Tenon氏囊成纤维细胞的体外培养

目的 探讨人眼Tenon氏囊成纤维细胞的体外培养方法,为防治眼部纤维增殖性疾病提供理想的细胞模型.方法 应用组织块和混合消化液培养法,取人角膜移植供体眼Tenon氏囊进行体外培养,并对培养的传代细胞进行液氮冻存复苏和形态学的鉴定.结果 人眼Tenon氏囊成纤维细胞体外生长良好,经HE染色和免疫组化观察证明该细胞为成纤维细胞.冻存复苏后的细胞能继续传代生长,其形态学特点与冻存前基本一致.结论 人眼Tenon氏囊成纤维细胞在体外生长良好,并可长期液氮冻存.