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Biomedical subjects

C Bona

Publications and source records attributed to C Bona.

At least 145 records · Page 8Linked to original sources
PubMed1977

Nocardia water-soluble mitogen and lipopolysaccharide. Comparative study of two adjuvants and B-cell mitogens in mice.

The activity of Nocardia water-soluble mitogen (NWSM) and LPS were compared in several experimental systems, since both compounds are B-cell mitogens and polyclonal activators in vitro. The results reported here demonstrated that NWSM like LPS also has a strong adjuvant activity in vivo if administered in saline with a strong antigen (heterologous red blood cells) or even with a weak immunogen such as theta alloantigen. However, in contrast to LPS, NWSM administered to mice failed to induce in vivo proliferation of lymphocytes, polyclonal activation and PFC against syngeneic bromelain-treated erythrocytes and thymocytes. It is possible therefore, that different mechanisms may be responsible for adjuvant activity of NWSM and LPS.

Adjuvants, Immunologic↗
PubMed1976

Stimulation of lymphocytes by purified protein derivative: suppression by cells from human vaccinated with Bacille Calmette-Guérin.

Specific stimulation of thymus-derived cells by purified protein derivative or tetanus toxoid was inhibited by autologous lymphocytes. The lymphocytes, which were collected from healthy humans who had been vaccinated with bacille Calmette-Guérin were purified on nylon columns after removal of cells that form rosettes with sheep erythrocytes. The degree of purification of the lymphocytes was controlled by appropriate techniques.

B-Lymphocytes↗
PubMed1976

Failure to suppress theta antigenic expression in progeny derived from pre-immunized maternal recipients.

One possible theory concerning the success of the fetus as an allograft has been attributed to maternal modification of foreign fetal antigenic expression. In this respect progeny derived from pre-immunized maternal mouse recipients, have been examined for any modification (reduction) of corresponding theta antigen determinants. Two major groups of mice were examined. The first group of embryo transplantation derived AKR homozygotes born from pre-immunized CBA recipients whilst producing the corresponding anti-thetaAKR antibody activity. The second group of naturally derived reciprocal (CBA x AKR)F1 heterozygotes were also born from pre-immunized maternal recipients. In neither group was theta expression found to be modified and the significance of this finding is discussed in respect of other situations where fetal antigenic expression is known to be altered by maternal influence.

Animals↗
PubMed1976

Presence and subcellular localization of two distinct mitogenic fractions in the cells of Nocardia rubra and Nocardia opaca: preparation of soluble mitogenic peptidoglycan fractions.

Fractionation of cells of Nocardia rubra and Nocardia opaca led to the separation of the cell wall and a "cytoplasmic" fraction. Both fractions were mitogenic for the splenocytes of AKR and nude mice and of rabbits. The peptidoglycan was the active part of the cell wall fraction. The products solubilized by the action of Streptomyces albus G peptidases on the peptidoglycan of N. rubra were mitogenic, but the products solubilized by lysoyme were not. Tentative structures are proposed for these fractions. The most active part of the cytoplasmic fractions could be sedimented by centrifugation and seemed to be related to the cytoplasmic membrane.

Animals↗
PubMed1976

Resemblance of blast responses of C3H/HeJ mouse and rabbit spleen lymphocytes to B-cell mitogenic components of E. coli cell walls.

Nude mice lymphocytes were stimulated by heat-killed E.coli bacterial cells as well as by various components of their cell walls such as lipopolysaccharide, peptidoglycan and lipoprotein. Only bacterial cells, peptidoglycan and lipoprotein induce a high stimulation of C3H/HeJ mouse and rabbit lymphocytes. These data show the resemblance of mutant C3H/HeJ mice to rabbits with regard to blast response induced by various mitogenic components of E.Coli cell walls.

Animals↗
PubMed1976

Cell suppression in PPD-induced blast specific response of human peripheral blood lymphocytes.

Secific stimulation of T-cells by PPD was inhibited by their autologous B cells. This inhibition was obtained with B cells separated either by depletion of E-RFC or by elution, with human IgG of lymphocytes bound to Sephadex beads coated with rabbit antibodies anti-human Fab fragments. The suppression was proportional to the number of B cells added to 10(6) T cells incubated with PPD and as previously reported was more marked in the case of B or T cells from BCG-vaccinated subjects with negative skin tests. The suppressive phenomenon required viable B cells and was inhibited by cycloheximide but was not altered by pretreatment of suppressor cells with actinomycin D or colchicine. It seems that B-suppressor cells interfere with recognition of PPD by T cells rather than with the proliferative phase of the specific blast response. Using various surface markers (i.e. Ig, C3 and Fc receptors) it was shown that the suppressor cells represent a subset of Ig-bearing B cells which do not carry Fc receptors.

Antigens↗
PubMed1976

A human T-independent B lymphocyte mitogen extracted from Nocardia opaca.

Nocardia water soluble mitogen (NWSM), a mitogen specific for mouse and rabbit B cells, activates blood, spleen, and tonsil lymphocytes from all the humans tested. Evidence is presented that it acts selectively on human B lymphocytes. B-enriched cells were recovered from anti-Ig-coated Sephadex columns or after elimination of E rosette-forming cells: they were able to incorporate tritiated thymidine when they were cultivated in the presence of NWSM whereas they were not activated by PWM. Conversely T-enriched suspensions did not respond to NWSM although they were able to be stimulated by PHA and PWM. Moreover, the response to NWSM remained unchanged after T cells had been killed by anti-HTLA serum and complement and disappeared after B cells had been killed by anti-HBLMA serum. After stimulation by NWSM, the number of direct plaque-forming cells to HRBC, LPS, and TNP was significantly increased, showing a polyclonal activation of human B lymphocytes. Since no evidence of T cell help for B cell activation has been found, NWSM thus appears to be a T-independent human B lymphocyte mitogen.

B-Lymphocytes↗
PubMed1975

[Adjuvant and mitogenic effects of detoxified lipopolysaccharides].

McIntire and al. have observed that a lipopolysaccharide (LPS) extracted from E. coli could be detoxified by succinylation or phtalylation and remained capable of enhancing the immune respose to serum albumins. The data reported here confirm that several LPS preparations after treatment by phtalylation retained their adjuvant activity when injected with bovine serum albumin or influenza vaccine. Yet their toxicity (as measured in adrenalectomized mice) was at least 10 000-fold smaller. Furthermore it was observed that after phtalylation LPS could still induce blastic transformation of murine B-derived lymphocytes. Thus it was possible to dissociate the toxicity of LPS from both its adjuvant and mitogentic activities.

Adjuvants, Immunologic↗
PubMed1975

Human lymphoblast cell lines: antibody-dependent cytotoxicity.

Five cell lines were isolated after prolonged culture of human buffy coat leukocytes. The cells consisted for the most part of lymphoblasts morphologically similar to those produced by in vivo or in vitro stimulation of small lymphocytes by antigens or mitogens. One of the lines possessed virus-like particles of the Epstein-Barr type. All the established lines were capable of mediating antibody-dependent cytotoxicity (LADC) quantitatively at a level not significantly different from that mediated by freshly isolated, normal human peripheral blood lymphocytes (PBL). The LADC of the lymphoblasts was inhibited by all the human IgG subclasses tested (IgG1, IgG2, IgG3, IgG4) as was the LADC of PBL. It is concluded that, at least so far, the lymphoblasts have retained the properties of the lymphocytes from which they were originally derived as regards their ability to mediate LADC.

Antibodies↗
PubMed1975

Isolation of mitogenic and adjuvant active fractions from various species of Nocardiae.

Delipidated lysozyme digests of Nocardia opaca, N. corallina, and N. rubra have been fractionated by Sephadex filtration. The mitogenic and adjuvant activities of the fractions thus obtained have been investigated. All fractions are mitogenic except the last fraction of N.rubra, but the N. opaca products induce a stronger stimulation of mouse spleen lymphocytes than the corresponding fractions of the two other species. The activity of the first Sephadex fractions of each strain has been compared to other mitogens (concanavalin A, lipopolysaccharide). All fractions are adjuvant, although one of them, the last Sephadex fraction of N. rubra, does not contain peptidoglycan; its activity must thus be attributed to another kind of molecule. Fractionation of the first Sephadex fraction of N. opaca by centrifugation in glacial acetic acid led to a separation of adjuvant and mitogenic activities.

Adjuvants, Immunologic↗
PubMed1975

Biological activities of endotoxins detoxified by alkylation.

It has been previously observed that lipopolysaccharides can be detoxified by alkylation and yet retain their adjuvant activity. Our present findings confirm these results and show, moreover, that these derivatives did not lose their capacity to protect mice against lethal irradiation and lost only partially their ability to interrupt pregnancy or to induce blast transformation of murine B-lymphocytes. However, in contrast with lipopolysaccharides, these alkylated preparations did not enhance the nonspecific resistance of mice to a bacterial infection. The various bilogical functions of endotoxins can therefore be separated and are not uniformly related to their toxicity.

Abortion, Spontaneous↗
PubMed1975

Blast transformation of rabbit B-derived lymphocytes by a mitogen extracted from Nocardia.

Nocardia water soluble mitogen (NWSM) is known to stimulate mouse and rabbit lymphoid cells and to act selectively on murine B-derived lymphocytes. In this paper, evidence is presented that NWSM is also a mitogen for rabbit bursal equivalent cells and does not bring about blast transformation of thymus-derived rabbit cells. Pretreatment of rabbit spleen lymphocytes with antibody directed against rabbit thymus lymphocyte antigen (anti RTLA serum) and with complement did not affect the strong increase of thymidine incorporation which follows stimulation with NWSM. The mitogen-induced polyclonal activation of antibody-forming cells and resulted in the presence of 30% of cells with the ultrastructural characteristics of plasmocytes. These observations led to the conclusion that NWSM is a mitogen for a B-derived lymphocyte of the rabbit.

Animals↗
PubMed1975

Physiological significance of the lymphocytic cell coat.

The lymphocytes are coated by an external glycoprotein layer the so-called cell coat. There is some difference between the structure of the cell coat of T- and B-derived lymphocytes. The cell coat represents the chemical basis of some lymphocytic properties, i.e. their homing and electrophoretic mobility and it plays and important role in the expression of antigenicity of lymphocytes and the triggering of blast transformation.

Animals↗