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In vitro cultures of native fish cell lines are of great importance, both for basic research and applied science. In particular, there is strong demand for long-term growable cell lines from breeding fish, like sturgeon. Here, we describe the culture of cells from Siberian sturgeon (Acipenser baerii) head kidney. The cells have so far been cultured over a period of 12 months (24 passages). Cytochemical and immunocytochemical examination suggests that, in vitro, the cells exhibit markers that are indicative for different cell types. In particular, fat storing cells (adipocytes) were observed, and the expression of cytokeratins and glial fibrilar acidic protein (GFAP) can be concluded on the basis of immuncytochemical analysis. The observation of different morphologies additionally underlines the heterogeneity of the cell population and matches the typical behaviour of in vitro cultures of stem/progenitor cells. Different applications can be imagined.

In mammals, erythropoietin regulates the development and differentiation of erythrocytes. Although hematopoietic cells of bony fish correspond in their ontogeneic development, morphology, and function to their mammalian counterparts, an erythropoietin (EPO)-like molecule has not been identified. In this study we present evidence for a mitogenic response of blood and head kidney leukocytes of rainbow trout after stimulation by recombinant human EPO (rhu EPO). The modulation of cellular activities is accompanied by the induction of DNA-binding activities in nuclear extracts of these cells. In addition, flow cytometric analysis of intracellular Ca2+ concentrations revealed a long-lasting and rhu EPO dose-dependent increase, which was shown to be abrogated by cross-aggregation of surface IgM using anti-trout-IgM monoclonal antibodies (mabs). In flow cytometric dual-labeling experiments using rhu EPO/anti-EPO antiserum and mabs specific for trout leukocyte subpopulations, it was shown that a subpopulation of trout B-cells binds rhu EPO. Moreover, in a modified Ca2+ activation assay, it was demonstrated that this blood B-cell subpopulation is the rhu EPO responder population. In conclusion, the data suggest the existence of EPO-binding receptors in trout that are able to trigger Ca(2+)-independent intracellular signaling in hematopoietic cells of head kidney and Ca(2+)-dependent activation of a subpopulation of B-lymphocytes.

In this paper we show that there exists a free convenient vector space for the case of holomorphic spaces and holomorphic maps. This means that for every spaceX with a holomorphic structure, there exists an appropriately complete locally convex vector space λX and a holomorphic mapl X:X→λX, such that for any vector space of the same kind the map (l X )*:L(λX,E)→ℋ(X,E) is a bijection. Analogously to the smooth case treated in [2, 5.1.1] the free convenient vector space λX can be obtained as the Mackey closure of the linear subspace spanned by the image of the canonical mapX→ℋ(Xℂ)′. In the second part of the paper we prove that in the case whereX is a Riemann surface, one hasλX=ℋ(X,ℂ)′.

Engineering graduate student experiences in an online pilot course about teaching science and engineering are the focus of this work-in-progress. Their experiences from fall, 2006 are the center of the on-going research that compares their experiences with engineering graduate students who completed the traditional, face-to-face, semester-long campus course and those who completed the traditional, face-to-face, two-week course. Case studies will demonstrate how six engineering graduate students (two from each format) learned about teaching science and engineering when they were participating in an interdisciplinary course; engineering students were the minority and worked with chemists, physicists, geologists, and other STEM graduate students. The research questions is how, if at all, the interdisciplinary, online context makes a difference in student learning. This on-going pilot program involves web-conferences, a course management system, and seven institutions associated with the Center for the Integration of Research, Teaching, and Learning (CIRTL). The effectiveness of online learning experiences is significant as we prepare and support future faculty; we expect to learn that students appreciate diverse formats and opportunities, will choose those that work for them, learn consistently across all formats, and gain the added benefit of learning how to work collaboratively at a distance. By the conference date, we will be midway through the second online course and data collection. Our evaluation plan consists of pre and post surveys, authentic assessments, and in-depth interviews for the students who are the focus of the case studies.

The internalization of the gold labelled monoclonal antibody RoMo-1 recognizing the CD 14 surface molecule of human monocytes was studied by electron microscopy. Monocyte enriched mononuclear cells (MNC) from the peripheral blood of healthy donors were incubated for 15, 30, 60, and 90 min with gold marked RoMo-1 in Eagle MEM at 37 degrees C. The process of internalization of RoMo-1 occurs as a receptor mediated endocytosis (RME), as described for other ligands.

An anti-CD14 mAb RoMo-1 rapidly induces in human monocytes a transient oxidative burst activity as detected by chemiluminescence assay. Pretreatment of these cells with the mAb markedly suppresses the monocyte chemiluminescence response to opsonized zymosan. In addition, the antibody induces a significant increase of IL-1 production and secretion by mononuclear cells, comparable to a similar effect of rIFN-γ or LPS. Electron microscopy demonstrates internalization of the CD14 molecules after interaction with the mAb in a characteristic receptor-like manner.

The immune response of mice bearing a transplantable tumor which was induced by Benzyprene was studied. The humoral response to sheep red blood cells (hemolytic plaque assay) is increased until the day 18 after inoculation of the tumor if calculated in relation to the total number of spleen cells, but it is decreased related to 10(6) spleen cells after day 9. Because the weight of the spleen increases during this time this result suggests that the relation between antibody producing and nonproducing cells becomes smaller, despite the total number of antibody producing cells is higher. The unspecific suppression of the cell-mediated immune response in vivo was was studied by the adoptive transfer of spleen cells from tumor bearing mice and allografting of the recipients. The rejection of the grafts is delayed. The stimulation of spleen cells with PHA is smaller with cells from tumor animals than in controls. The fraction which is nonadherent on glass beads has a higher reactivity than the total population, this difference is more distinct in tumor animals. The suppressor cells from tumor mice are glass adherent and their activity is negatively influenced by treatment of the tumor mice with Carageenan.

Sera from normal, allogeneically hyperimmunized and transplantation tolerant mice show an inhibitory effect on MLR and PHA stimulation. After gel chromatography these inhibitory factors are preferably found in fraction III for MLR (MW 250-750 KD) and III and IV for PHA stimulation. These factors are not identical with the IL-2 inhibitor. A specific inhibitory component with a MW of about 1000 KD is found in sera from transplantation tolerant mice. This suppressor factor could have a synergistic function in induction of specificity and activity of suppressor cell.

The stimulation rate with PHA of murine spleen cells increases after removal of glass-adherent cells from the total spleen population. Unfractionated spleen population from HC treated mice suppresses the response to PHA of glass non-adherent cells from untreated animals only 24-48 h after HC treatment. From the third day on after the treatment the suppressive effect disappears.

Allogeneic sensitization in vivo results in cytotoxic lymphocytes specific in cytotoxic reactions against thymus cells as target cells. Only those targets are destroyed which have common private determinants with the stimulator cell. Target determinants on the K end of the histocompatibility complex are mainly responsible for cell lysis. Alloantibodies block specifically the cytotoxic reaction. First of all blocking activity is directed against the private determinant of the K end. Alloantibodies against public determinants from other H-2 incompatible combinations don't influence the cytotoxic reaction. The blocking antibodies belong mainly to the IgG class but antibodies of the IgM class show a inhibitory activity too.

After allogeneic skin grafting and allogeneic sensibilization with spleen cells in the mouse system cytotoxic lymphocytes are induced, which can be shown in an vitro assay. The maximum of the cytotoxicity appears 2 to 3 days after transplantation. Cytotoxicity during graft rejection is clearly lower than the maximum cytotoxicity. After 3 to 4 weeks no cytotoxic lymphocytes can be detected. A similar time course is seen after sensibilization with allogeneic spleen cells. The cytotoxic lymphocytes do not react only against the stimulator haplotype if tumor cells are used as target cells. Common specificities between the stimulator and target cells may be responsible for this cytotoxicity. On the other side we found a specific cytotoxic reaction with thymocytes as target cells and in vivo no cross reaction for a second-set graft rejection.

The importance of the receptor ligand system IL 2-receptor and IL 2 for the regulation of the T-cell proliferation was confirmed recently. In this review most important points are discussed as biochemical data, regulation of the expression, monoclonal antibodies, binding behaviour, affinity and activation events. Other activation antigens are also discussed in a short part.

GvH reactions were induced in (CBA X C57B1)F1 and (CBA X A)F1 mice with sensitized lymphocytes. Specific sensitization results in an increased GvH reaction, sensitization against third party cells does not influence the GvH reaction. Therefore serologically defined public antigens of the H-2 system play not role in the GvH reaction. The comparison of different numbers of specifically sensitized lymphocytes, lymphocytes sensitized against third party cells, and control lymphocytes for the induction of the GvH reaction leads to the same result.

The effect of foetal liver cells on GVH reaction with the parental lymphocytes in F1 hybrid mice was studied. The GVH reaction was induced in newborn (CBA X C3H)F1 and in 10-day-old (CBA X C57BL/6)F1 hybrid mice. Foetal liver cells did not induce a GVH reaction. The GVH reaction of CBA spleen cells in (CBA X C3H)F1 hybrid mice was demonstrable, although weak. Foetal liver cells suppressed the GVH reaction, in dependence on cell concentration, in (CBA x C3H)F1 but not in (CBA X C57BL/6)F1 hybrid mice. The possibility to induce transplantation tolerance with foetal liver cells is discussed.

The monoclonal IgG2a-antibody RoMo-1 binds to peripheral human blood monocytes but does not react with other blood cells, tissue macrophages, HL-60, K 562 or U 937. It seems possible, that the antibody defines an antigen expressed on the premonocytic and monocyte stages of cells from the mononuclear phagocytic system only. The antibody is cytotoxic.

A monoclonal antibody reacting with human MHC class II molecules was prepared. This antibody, RoDR, is directed against a nonpolymorphic determinant on DR, but not DP or DQ molecules.

Transfer of neonatally induced tolerance in the H-2 compatible CBA/C3H strain combination is possible with different efficiency by injection of adherent and non-adherent spleen cells, unseparated spleen cells and lymph node cells from C3H-tolerant CBA mice into sublethal irradiated CBA mice. The most efficient cell populations are adherent spleen cells and lymph node cells. Successful transfer of transplantation tolerance is not possible to non-irradiated mice. The adherent fraction of spleen cells and lymph node cells contains a suppressor cell population responsible for transplantation tolerance against non-H-2 antigens. The induced transplantation tolerance is not due to a chimaeric state of C3H-tolerant CBA mice.

Transplantation tolerance is used as model for investigation of mechanisms in recognition of "self" and "non-self". The clonal deletion of specific lymphocytes as reason transplantation tolerance is called more and more in question. Active mechanims, as for instance induction and maintenance by suppressor cells are more possible. Suppressor cells may be active not only in inhibition of inductor phase but also in blocking of effector cells. A synergistic effect of blocking factors is supposed too. The thymus plays an important role in induction of transplantation tolerance. Different methods for induction of tolerance are described.