Cellular immunity in pyelonephritis: identification of suppressor cell activity of spleen cells in response to concanavalin A and inhibition of lymphocyte-mediated L cell cytotoxicity.

A population of fast sedimenting spleen cells was identified as the cause of impaired in vitro response of spleen cells to concanavalin A (Con A) in acute pyelonephritis in rats. These fast-sedimenting cells responded to Con A by suppressing the DNA synthetic response of normal spleen cells to Con A. In addition, spleen cells from acute pyelonephritis rats were significantly less able to mediate in vitro cell destruction in xenogeneic aggressor lymphocyte: target L cell mixtures. On the basis of these findings, the hypothesis is proposed that a suppressor cell can protect the pyelonephritic kidney against immunologically mediated tissue damage.     

Role of non-RT1 genes in the response of rat lymphocytes to Mycoplasma arthritidis T cell mitogen, concanavalin A and phytohemagglutinin

A comparison of splenic cells from various inbred rat strains indicated that DA, Lewis, Buffalo, August, Wistar Furth, and (LEW X BN)F1 all responded well to the Mycoplasma arthritidis T cell mitogen, phytohemagglutinin and concanavalin A, but cells from BN and MAXX rats were very weakly or nonresponsive. Cells from congenic strains expressing nonresponder background genes, and responder haplotypes at RT1 (BN.1L(LEW), RT1; BN.1A(DA), RT1av1) failed to respond significantly to the mitogens. Rats expressing responder background genes but the nonresponder haplotype at RT1 at RT1 (WF.1N-(MAXX), RT1n) exhibited high responses to all mitogens. The controlling role of non-RT1 genes was confirmed by testing tissue-typed (DA X BN)F2 progeny and (DA X BN)F1 X DA and (DA X BN)F1 X BN progeny. No association was seen between the expression of a/a, a/n, or n/n at RT1 and the degree of response to the mitogens. In contrast, as the proportion of DA non-RT1 genes increased, so did the degree of mitogenic responsiveness. Similar results were obtained by using a partially purified preparation of the mycoplasma T cell mitogen. The results indicated that in the (DA X BN)F1 hybrids, responsiveness to all mitogens was recessive: this contrasts with the (LEW X BN)F1 hybrids in which responsiveness was dominant. Finally, we showed that both responder and nonresponder splenic cells were capable of binding the M. arthritidis mitogen. The data contrast with those obtained with nonresponder mouse strains the cells of which failed to bind mitogen due to the absence of the E alpha chain of the I-E-coded molecule.     

Lens culinaris lectin is a T-cell mitogen: binding inhibition by concanavalin A and phytohemagglutinin-P.

Binding and mitogenicity of a lectin from Lens culinaris (LcH) were studied in mouse lymphocytes. Both continuous and pulse treatment of lymphocytes with LcH induced a mitogenic response selectively in T cells. LcH and Con A, which have similar binding specificities, exhibited binding inhibition both in unfixed cells and glutaraldehype-fixed cells, with native Con A and succinyl Con A and at 37 °C as well as 0 °C. On the other hand, reciprocal binding inhibition by a third T-cell mitogen, phytohemagglutinin-P (PHA-P), was found only in unfixed cells at 37 °C and with native Con A, indicating that the inhibition is a secondary effect as opposed to direct competition for receptors. The inhibition of mitogenic responses to LcH and PHA-P by pretreatment of cells with Con A was studied in relation to the two different types of binding inhibition. Only the type of binding inhibition caused by a secondary effect correlated with interference with the mitogenic response.     

Cellular events during the primary immune response in the spleen

Summary The cellular events during the primary immune response in T and B cell compartments in the splenic white pulp were analysed in germfree mice immunized with sheep erythrocytes. Light, fluorescence and electronmicroscopic studies revealed that the initial formation of lymphoid blast cells occurs in the thymus-dependent area, i.e. the central periarteriolar lymphatic sheath (central PALS), 2 days after immunization. Lymphoblasts were found in close relation with erythrocyte-containing macrophages and with interdigitating cells. With fluorescence microscopy these blast cells were Ig negative. Lymphoblasts in the central PALS showed many polyribosomes in the cytoplasm, but were virtually devoid of endoplasmic reticulum. The ultrastructure of lymphoblasts in the central PALS, and their relation with interdigitating cells, suggests that these cells are the progeny of antigen-activated T cells.Cells with a positive cytoplasmic fluorescence, plasmablasts, appeared 3 days after immunization in the peripheral part of the PALS. During the progress of the immune response these cells accumulated around branches of the central arteriole, and moved along marginal zone bridging channels towards the red pulp. In the electron microscope plasmablasts showed many polyribosomes, short strands of rough endoplasmic reticulum close to mitochondria, and a few electron-dense bodies. The cell organelles of plasmablasts were frequently gathered in a so called uropod, which is a morphological sign of active cell movement.Germinal center formation started within primary follicles, 4 days after immunization. Blast cells in germinal centers did not show cytoplasmic fluorescence. During the course of the immune response, germinal centers extended in diameter, and fluorescent dendritic cells appeared at the periphery of the germinal center.From the present observations we conclude that: (1) cellular cooperation between different lymphoid and non-lymphoid cell types during the immune response against SRBC takes place in the PALS, (2) the cellular cooperation in the PALS results in the differentiation of B cells into immunoglobulin-producing plasmablasts, (3) the cellular cooperation in the PALS preceeds the formation of germinal centers in primary follicles, hence germinal centers are not involved in early T-B cell cooperation.     

Approach to the mechanism of Zajdela's hepatoma cell growth inhibition induced by concanavalin A and phytohaemagglutinin

Cell growth of tumour ascites cells was inhibited by concanavalin A, phytohaemagglutinin and Ricinus lectin at 2-100 micrograms/ml. As expected, the Ricinus lectin inhibited the protein synthesis estimated by leucine incorporation and decreased thymidine incorporation, whereas concanavalin A and phytohaemagglutinin stimulate the uptake and the incorporation of both leucine and thymidine, and thus, synthesis of protein and DNA. These results suggest that different mechanisms are involved in the hepatoma cell growth inhibition by the lectins. This difference was not related to the kinetic characteristics of the lectin interactions with the cells which represent a first and necessary step. It was showed that concanavalin A and phytohaemagglutinin as well as chloroquine inhibited the 14C-labelled asialofetuin degradation. We can conclude that Ricinus lectin present a toxic effect whereas both concanavalin A and phytohaemagglutinin show an anti-protease activity.     

Antigen-specific helper factors present in the supernatant of concanavalin A-induced spleen cell cultures

The supernatants from cultures of concanavalin A-induced spleen cells contained both antigen-specific and nonspecific (Interleukin 2) helper factors (Hf). The antigen-specific factor could be isolated from the supernatant by adsorption onto and elution from antigen-Sepharose immunoadsorbents. Specific Hf was produced in cultures of either immune or nonimmune spleen cells although in the latter case the quantity of Hf was significantly less. The specific Hf did not manifest the thymocyte stimulatory property of 112.     

Effects of the mitogen concanavalin A on pathways of thymocyte energy metabolism.

The lectin concanavalin A (Con A) acts as a mitogen that preferentially activates T-cells. It stimulates the energy metabolism of thymocytes within seconds of exposure. We studied short-term effects (<30 min) of Con A on a conceptually simplified model system of rat thymocyte energy metabolism in the concentration range of 0-2 microg Con A per 107 cells, using metabolic control analysis. The model system consisted of three blocks of reactions, linked by the common intermediate mitochondrial membrane potential (Delta[psi]m): the substrate oxidation reactions, which produce the linking intermediate, and the proton conductance (or leak) and ATP turnover pathways which consume Delta[psi]m. Firstly, we used top-down elasticity analysis to establish which subsystems are targeted by Con A. Secondly, we quantitatively analysed the steady-state regulation of the system variables by Con A: how do the subsystem fluxes respond to Con A individually and as a whole? Our results indicate that: (1) steady-state respiration and Delta[psi]m increase as Con A concentration is raised, but at higher concentrations the increase in respiration is less and Delta[psi]m falls; (2) Con A independently changes the kinetics of the reactions that produce and consume Delta[psi]m: the Delta[psi]m-producing reactions are inhibited, and the reactions involved in ATP turnover are stimulated; and (3) the overall effects of Con A are mostly mediated by effects on ATP turnover.     

Immunological reconstitution of T-cell-deprived mice. I. Inability of thymosin to restore spleen cell mitogen and tumor allograft response.

Ultraviolet light (uv)-induced tumors appear to possess unique and common determinants, both of which can function as rejection antigens in appropriate in vivo tumor transplantation assays. We postulate that the common tumor antigens can play an important role in anti-tumor immunity. We have previously reported on the phenomenon of ultraviolet light generated suppressor lymphocytes which mediate susceptibility to transplanted uv-induced murine skin tumors. We now report that these uv generated suppressor cells are capable of specifically inhibiting effector responses directed against the common tumor antigens. A hypothesis is presented to explain how the presence of suppressor cells might account for the observed differences between in vivo and in vitro assays of tumor immunity.     

Cellular transfer of experimental allergic encephalomyelitis in Lewis rats: Effects of different sensitization regimens on in vitro reactivity of donor spleen cells to concanavalin A

Splenocytes from Lewis rats sensitized to guinea pig spinal cord (GPSC) and complete Freund's adjuvant (CFA) or to myelin basic protein (MBP)-CFA plus pertussis vaccine were less effective than spleen cells from MBP-CFA sensitized donors in transferring EAE to syngeneic recipients following culture with concanavalin A (Con A). Moreover, splenocytes from rats sensitized to GPSC-CFA plus pertussis vaccine showed no EAE transfer activity following culture with Con A. Diminished EAE transfer activity occurred in parallel with decreased proliferative responses of primed splenocytes to Con A. These effects were due, at least in part, to the use of pertussis vaccine and to Con A activation of a suppressive adherent cell subpopulation in sensitized donor spleens. Proliferative responses and EAE transfer activity were restored upon removal of plastic-adherent cells from splenocytes of rats sensitized to MBP-CFA plus pertussis vaccine prior to Con A activation of the non adherent lymphoid cells. Deletion of plastic-adherent cells from splenocytes of donors sensitized to GPSC-CFA plus pertussis vaccine prior to activation with Con A, however, had no effect on proliferative responses or EAE transfer activity. Furthermore, EAE transfer activity of Con A-activated splenocytes from MBP-CFA-sensitized donors was lost when such cells were cultured with splenocytes from donors sensitized to GPSC-CFA plus pertussis vaccine.     

Cellular immunity to Hodgkin's splenic tissue measured by leucocyte migration inhibition.

Patients with lymphoreticular malignancy were shown by a leucocyte migration inhibition technique to have cellular immunity to Hodgkin''s splenic tissue. Migration was significantly inhibited in 31 out of 55 patients with Hodgkin''s lymphoma and 19 out of 39 patients with other types of lymphoma. Inhibition was also shown in only three out of 29 patients with other malignancy, one out of 23 normal volunteers, and one out of 25 patients with non-malignant disease. The splenic factor that inhibits leucocyte migration, which has yet to be isolated and identified, may be a helpful diagnostic tool in patients with suspected lymphoma.     

Electrokinetic response of granulocytes to concanavalin A and succinyl-concanavalin A

Electrophoretic light scattering has been used to study the effects of concanavalin A (Con A) and succinyl-Con A on the electrophoretic mobility distribution of resident guinea-pig peritoneal eosinophils and human peripheral blood polymorphonuclear leukocytes. In both cell types, incubation with Con A (a tetrameric lectin) decreases slightly the mean mobility and increases substantially the width of the electrophoretic mobility distribution. These effects can be abolished by alpha-methyl-D-mannoside, a hapten sugar of Con A. Succinyl Con A, a dimeric derivative, was found to have no effect on the mobility distribution. These results are strikingly similar to our previous report of the response of the resident guinea-pig macrophage (19), suggesting possible parallels in the endocytic mechanisms of these cell types.     

Electrokinetic response of granulocytes to concanavalin A and succinyl-concanavalin A

Electrophoretic light scattering has been used to study the effects of concavalin A (Con A) and succinyl-Con A on the electrophoretic mobility distribution of resident guinea-pig peritoneal eosinophils and human peripheral blood polymorphonuclear leukocytes. In both cell types, incubation with Con A (a tetrameric lectin) decreases slightly the mean mobility and increases substantially the width of the electrophoretic mobility distribution. These effects can be abolished by α-methyl-D-mannoside, a hapten sugar of Con A. Succinyl Con A, a dimeric derivative, was found to have no effect on the mobility distribution. These results are strikingly similar to our previous report of the response of the resident guinea-pig macrophage (19), suggesting possible parallels in the endocytic mechanisms of these cell types.     

Induction of IL-2 receptor expression in vivo: response to concanavalin A

The requirements for the induction of IL-2 receptor expression following lymphocyte stimulation in vitro are well understood but little is known about the role of IL-2 and the IL-2 receptor in lymphocyte activation in vivo. Following the subcutaneous injection of concanavalin A, cells from popliteal and lumbar lymph nodes draining the footpad became enlarged and expressed the IL-2 receptor. At the peak of the response, 9-15 hr after injection, more than 70% of all cells were IL-2 receptor positive; the majority were T cells of both Lyt-2+ and L3T4+ subsets. IL-2 receptor expression was closely associated with both spontaneous and IL-2-driven proliferation. Analysis of the biodistribution of 125I-labeled concanavalin A revealed that much of the injectate remains in the footpad injection site but the mitogen also accumulates in the draining lymph nodes and eventually in the major organs. This model of lymphocyte activation was used to demonstrate that in vivo cyclosporin A inhibits both IL-2 receptor expression and the induction of spontaneous proliferation.     

Degree of proliferative response to concanavalin A of spleen cells of mice of different strains and production of interleukin-2

Differences in the lymphoproliferative response to Con A of spleen cells allowed one to distinguish a high responder (BALB/c and DBA/2) and low responder (C57BL/6 and CC57BR) mice. BALB/c and DBA/2 mice (H-2d haplotype) produced interleukin 2 better, than C57BL/6 and CC57BR mice (H-2b haplotype). However acceptance of interleukin 2 was better in BALB/c and C57BL/6, than in DBA/2 and CC57BR mice. Summarizing these facts the authors suppose that the differences in interleukin 2 production and acceptance play an important role in the height of lymphoproliferative response.