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991.
Murine splenic B lymphocytes are induced to proliferate and undergo polyclonal activation in the presence of Fc fragments, AHGG, antigen-antibody complexes, and CH3 fragments derived from plasmin digestion of human Ig. The unifying feature of the polyclonal antibody response induced by these agents is that in all cases a portion of the constant region of the Ig molecule (ie, Fc region) is present. Fragments of Ig lacking the Fc piece, such as Fab and F(ab′)2 were found not to be stimulatory. In addition, a model is proposed to account for the regulatory effects of antigen-antibody complexes on an ongoing humoral immune response. 相似文献
992.
993.
Selective isolation and culture of a proliferating epithelial cell population from the hamster trachea 总被引:7,自引:0,他引:7
William E. Goldman Joel B. Baseman 《In vitro cellular & developmental biology. Plant》1980,16(4):313-319
Summary A reliable cell isolation technique was developed to allow the cultivation of cells from the hamster respiratory tract. Repeated
thermolysin treatments and gradient centrifugation yielded a cell culture completely free from contamination by fibroblasts.
Viable cells could be isolated from as little tissue as a single hamster trachea, but in vitro proliferation occurred only
if the hamster was less than 4 months of age. The cultured cells could be repeatedly passaged and subcultured for weeks by
employing normal tissue culture techniques. Morphologically, the monolayers appeared to be a homogeneous population of epithelial
cells, and successful cloning of freshly isolated single cells resulted in apparently identical cultures. The epithelial origin
of these cells was also suggested by continued growth in minimum essential medium withd-valine substituted forl-valine. The relative ease with which this cell type can be isolated, cultured, and manipulated in vitro should encourage
its application as a model of the respiratory epithelium.
This research was supported by Public Health Service Grant P50-HL 19171 and Research Career Development Award 1-K04-AI 00178
to J. B. B. 相似文献
994.
William H. J. Douglas James A. McAteer Robert T. Dell'orco David Phelps 《In vitro cellular & developmental biology. Plant》1980,16(4):306-312
Summary A one-step vital stain is described for the macroscopic visualization of histotypic cell aggregates in fetal rat lung organotypic
cultures. Organotypic cultures are incubated in 0.05-0.1% 2,3,5′-triphenyl tetrazolium chloride (TTC) in culture medium (37°C).
Living cells reduce the tetrazole to a water-insoluble red colored formazan. Cell aggregates appear as densely stained foci
against the lighter background of the Gelfoam substrate. Stained cultures may be scanned macroscopically to determine the
degree of reaggregation and assess cell viability. Identification of aggregates by TTC staining improves the efficiency of
tissue processing for electron microscopy and does not alter the ultrastructural appearance of the cultured cells.
This work was funded in part by the United Cerebral Palsy Research and Educational Foundation, Inc. and the National Heart,
Lung, and Blood Institute (Grants 1ROHL19513 and 1 R01HL21008). 相似文献
995.
William A. Horton Nena Dockery David Sillence David L. Rimoin 《Biotechnic & histochemistry》1980,55(1):19-29
We have used glycol methacrylate to study undecalcified skeletal growth plate and subchondral bone. Minor modifications of the original technique including dehydration in glycol methacrylate vacuum infiltration and polymerization in the cold make it quite suitable for embedding of such tissues. Moreover, specimens can be processed quickly and the morphologic and biochemical integrity of the tissue retained so that histochemical procedures can be readily applied. Collagen, glycosaminoglycan, glycogen, lipid, calcium and the activity of alkaline and acid phosphatase were localized. This technique appears to be very useful for studying skeletal tissues. 相似文献
996.
William C. Wright 《In vitro cellular & developmental biology. Plant》1980,16(10):875-883
Summary A new calculation of the relative efficiency of polymorphic enzyme markers, called the REB, was determined and compared with
one of Fisher's determinations of the relative efficiency called REA here. The REA estimates the chance of failing, and 1-REA
of succeeding, to show a phenotypic difference between two randomly selected persons or cultured cell lines (Case 1). In this
study it was shown that the REA also estimates the chance of detecting a cell line mislabeling or similar mixup (Case 2) and
a cell line cross-contamination leading to the complete replacement of an original line by contaminating line (Case 3). The
new REB determines the probability of failing, and 1-REB of succeeding, to detect a contamination of an original line by another
line leading to their coexistence, or at least a sufficiently long period of transitional coexistence before one overgrows
the other. The REA and REB also apply to determining the efficiency of polymorphic markers in detecting donor and recipient
cells in tissue transplants.
This work was developed from the author's involvement in the human tumor cell-line characterization project at Sloan-Kettering
Institute and he acknowledges this opportunity and the benefits of his association with Dr. J?rgen Fogh and colleagues in
the Human Tumor Cell Laboratory. 相似文献
997.
998.
999.
William T. Starmer 《Microbial ecology》1982,8(1):71-81
Yeast communities of decayingStenocereus gummosus were analyzed for spatial, temporal, and physiological characteristics. Analysis of random samples within plants, between plants, and between localities shows that the species proportions of the yeast community are relatively constant within plants and between localities, but that there is significant variability between rotting plants. It is suggested that the increased variability between plants represents sampling of different stages of succession. The physiological abilities of the yeast community also show a relatively constant pattern within plants and between localities yet more variability between plants.The variablity profiles of species proportions and community physiological characters are demonstrated to be correlated within and between plants. This observation is an extension of the Kluge-Kerfoot phenomenon to the level of the community. The correlation of within and between plant variability profiles is suggested to be a result of the temporal and spatial availability of resources during the stages of rotting plant succession. The community structure is thus postulated to result from a set of possible future resource states of the habitat. 相似文献
1000.
Dr. William L. Elkins Giuliana Pierson William Negendank Karen S. Zier 《Immunogenetics》1982,15(5):485-499
Lymphocytes from an extensively transfused patient with aplastic anemia were induced to cytotoxicity against target cells from several HLA-matched siblings by in vitro stimulation with allogeneic cells. Effective stimulating cells shared HLA-B7 with the patient, but not all B7 individuals were effective. An additional factor, which was found to segregate in both the patient's and an unrelated sibship, was also necessary. Segregation of this minor alloantigen, W, was also revealed among the patient's HLA-matched sibs by differential susceptibility to lysis by effectors from the patient. The ratio of six positive to four negative siblings suggests that the antigen difference might be coded by a single locus. Lymphocytes from a normal sib, who like the patient is lacking the minor antigen, could not be induced to cytotoxicity against positive targets. Thus in vivo sensitization of the donor of the responding cells appears to be necessary for the demonstration of the cytotoxic response to the minor antigen in vitro. No correlation was observed between the segregation pattern of W and of known blood group antigens, and no cytotoxic antibody to W was detected in the patient's serum in several trials.Abbreviations used in this paper MHC
major histocompatibility complex
- Tc
thymus dependent cells capable of mediating cytotoxicity in the absence of Immoral antibody
- GVHD
graft versus host disease
- CML
cell mediated lympholysis
- MLC
unidirectional mixed lymphocyte culture
- ADCC
antibody-dependent cell mediated cytotoxicity 相似文献