Rosette formation in white blood cell cultures from patients with acute myeloblastic leukemia

Zusammenfassung In Monozyten enthaltenden Leukozyten-Kulturen von Patienten mit akuter myeloischer Leukämie entstehen nach ungefähr 8 h Inkubationszeit Rosetten, die aus einem von Myeloblasten umgebenen Monozyten bestehen. In Analogie zu anderen in vitro-Systemen, in welchen sich eine Rosettenbildung beobachten lässt, könnte diese zelluläre Reaktion auf dem Vorhandensein von spezifischen Antikörpern im Patienten-Serum beruhen, welche gegen die leukämischen Myeloblasten gerichtet sind.     

A lectin inNemopanthus mucronatus to papain treated porcine erythrocytes

Summary Extracts of the mountain holly,Nemopanthus mucronatus, contained an agglutinin to papain treated porcine erythrocytes but not untreated or neuraminidase treated cells. Human erythrocytes similarly treated did not react.     

Monospecific antibody plaque formation by spleen cells from mice immunized with sheep and chicken erythrocytes

Zusammenfassung Milzzellenaufschwemmungen von Mäusen, die mit einem Gemisch von Schaf- und Hühnererythrocyten einmal injiziert wurden, verursachen lokalisierte, hämolytische Zonen (antibody plaques), die nicht aus den beiden Zelltypen, sondern entweder nur aus Schaf- oder nur aus Hühnerzellen bestehen. Lymphatische Zellen, die gleichzeitig zwei verschiedene Hämolysine abscheiden können, sind in Milzzellenaufschwemmungen von zweifach immunisierten Mäusen anscheinend abwesend oder nur in ganz geringer Anzahl vorhanden.

---

---

The capable technical assistance of Mrs.Leony Mills during these studies is acknowledged. This investigation was supported in part by the U.S. National Science Foundation (Grant G-19581).     

Effects of prednisolone and butyrate on agglutinability of HeLa cells by concanavalin A

Cellular and Molecular Life Sciences - Agglutinability by concanavalin A was measured with HeLa65 cells grown with prednisolone or sodium butyrate, 2 compounds that increase the activity of the...     

Identification of cytotoxic cells responsible for lysis of target cells pretreated with concanavalin A in spleen populations of pregnant mice with suppressive activity]

During an alloimmunization, killer cells which lyse target cells only in the presence of a lectin are generated. That these cells, as well as suppressive cells, share immunocytological properties with specific killer cells, leads to the hypothesis that these cells may be concerned with the mechanism of immunosuppression. Two experimental results presented in this paper are consistent with this hypothesis: 1) Spleens from H-2k mice pregnant by H-2d males which bear a high suppressive activity also contain a relatively large number of killer cells having the ability to lyse Concanavalin A treated target cells and 2) supernatants of suppressive systems generated through an MLC block the cytolysis of specific target cells by the bound killer cells.     

Ultrastructural changes in dog thyroid follicular cells elicit by concanavalin A in vitro

Summary Dog thyroid follicular cells exposed to concanavalin A (Con A) in vitro showed changes in cell shape, induction of colloid droplets and alterations in the distribution of microvilli. Cells exposed to Con A plus suboptimal concentrations of TSH (thyroid stimulating hormone) showed pseudopods and their cytoplasm was virtually occupied with colloid droplets. This findings suggest that Con A potentiated pseudopod and colloid droplet formation induced by TSH.Acknowledgments. The authors gratefully acknowledge the expert technical assistance of J. M. Greco. Supported by V. A. Research Funds.     

Rosette formation by human T and B lymphocytes in the presence of adrenergic and cholinergic drugs

Summary It was shown that adrenergic drugs, which increase the intracellular levels of cAMP, inhibit the rosette formation by T-lymphocytes, but stimulate the rosettes produced by B-lymphocytes. Cholinergic drugs, which increase the levels of cGMP, on the contrary, stimulate the formation of rosettes by T-lymphocytes but inhibit those produced by B-lymphocytes.Acknowledgments. This investigation was supported by Grant from National Council for Scientific and Technological Development (CNPq), Rio de Janeiro, Brazil.     

Rosette formation by human T and B lymphocytes in the presence of adrenergic and cholinergic drugs.

It was shown that adrenergic drugs, which increase the intracellular levels of cAMP, inhibit the rosette formation by T-lymphocytes, but stimulate the rosettes produced by B-lymphocytes. Cholinergic drugs, which increase the levels of cGMP, on the contrary, stimulate the formation of rosettes by T-lymphocytes but inhibit those produced by B-lymphocytes.     

Morphological effects of concanavalin A on amphibian embryonic cells differentiating in vitro (author's transl)]

Concanavalin A exerts an irreversible inhibitory effect on the differentiation of cultured embryonic amphibians cells in vitro. Cytological changes and distrubances of cell attachment, and spreading to the culture support occur in parallel. Polykaryons have been noticed in treated cultures.     

Inhibition of DNA synthesis in concanavalin A stimulated rat lymph node cells by serum from arthritic rats

Summary Serum from adjuvant arthritic rats inhibits the mitogenic response of rat lymph node cells to concanavalin A, leaving unaffected the response to phytohemagglutinin. This activity is already evident 4 days after adjuvant administration and persists for at least 28 days.     

Inhibition of DNA synthesis in concanavalin A stimulated rat lymph node cells by serum from arthritic rats.

Serum from adjuvant arthritic rats inhibits the mitogenic response of rat lymph node cells to concanavalin A, leaving unaffected the response to phytohemagglutinin. This activity is already evident 4 days after adjuvant administration and persists for at least 28 days.     

Velocity sedimentation of tumor cells: A comparison of methods

Summary Tumor cells isolated from a murine fibrosarcoma were grown in primary culture for two days and then separated on a basis of size by velocity sedimentation. Centrifugal elutriation and STAPUT methods were compared for their ability to isolate biophysically unique tumor subpopulations. The isolated cell fractions were assayed for cell number, incorporation of triatiated thymidine and Coulter volume. Both methods were comparable with regard to ability to separate tumor cells on a basis of size. Elutriation had the advantage of speed but required sophisticated equipment. The STAPUT method was less expensive but required somewhat longer times for separation.Supported in part by NIH-NCI grants No. CA-06294 and CA-18628.     

Interaction of lead with erythrocytes

Zusammenfassung Untersuchungen mit²⁰³Pb in vitro ergeben, dass Blei in den Erythrozyten vorwiegend an Hämoglobin gebunden wird, während Stromasubstanzen kein Blei aufnehmen.     

A gelatin sponge model for studying tumor growth: quantitation of tumor cells and leukocytes in the CHO tumor

A gelatin sponge model system for tumor cell inoculation and retrieval of tumor-associated leukocytes is described. Gelatin sponges pre-implanted in nude mice harboring tumorigenic Chinese hamster ovary cells (line CHO) were examined at 2 and 11 days after injection of tumor cells for tumor cell content and leukocyte accumulation after digesting the sponge matrix in collagenase solution. The data indicate a progressive influx of host cells consisting primarily of macrophages, neutrophils and lymphocytes. The total number of viable tumor cells as well as the fraction of surviving tumor cells with clonogenic potential also increased with tumor age. Blank sponges not harboring tumor cells elicited an inflammatory response in the animals which did not change appreciably with length of sponge residence. However, when the sponges were harboring tumor cells, the accumulation of host leukocytes far exceeded that which occurred in blank sponges. This observation suggests a host response directed toward the tumor which is absent in animals bearing blank sponges. Apart from providing anchorage for injected cells, the gelatin sponge, by virtue of its digestibility in collagenase, makes possible the easy retrieval and precise quantitation of tumor-associated host cells.