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V S Sljivić

Publications and source records attributed to V S Sljivić.

At least 19 recordsLinked to original sources
PubMed1981

BCG, Corynebacterium parvum or Mycobacterium leprae added to cultures of BCG-primed mouse spleen cells cause an enhanced primary antibody response in vitro.

A few weeks after mice were injected i.v. with 10(8) live Mycobacterium bovis, BCG, the antibody response of their spleen cells to SRBC in vitro was comparable with the response of cells from untreated mice. Addition of BCG organisms to the culture vessels resulted in enhanced antibody-forming cell (AFC) responses by the primed cells but not by the cells from the untreated mice. No evidence was found for a direct stimulation of B cells and cell depletion experiments suggested macrophages were directly involved. BCG added to the cultures up to 68 h after they were set up, but not later, still caused enhancement. No enhancement was found when DNP-Ficoll was used as antigen. The ability to stimulate the anti-SRBC response was not restricted to the organism used for priming. Enhancement was also found if C. parvum or M. leprae were added to BCG-primed cells and if BCG was added to C. parvum-primed cells. The relevance of the results to the search for a leprosy vaccine is discussed.

Animals↗
PubMed1980

Active suppression masks an underlying enhancement of antibody production in vitro by spleen cells from BCG-infected mice.

The depressed antibody responses resulting from the administration of live BCG i.v. to mice have been investigated. The antibody response of spleen cells to SRBC or DNP-Ficoll in vitro was followed using Marbrook culture vessels. Depressed responses were also found in vivo confirming the results obtained in vitro. The response in vitro of normal spleen cells was suppressed by the addition of spleen cells from mice injected with BCG but not by the medium in which they had been growing for 2 days. The response of the normal spleen cells was also not suppressed by freeze/thaw disrupted BCG spleen cells, suggesting that the depressed responses in the mice injected with BCG are due to an active suppression by intact cells. This was confirmed by the cell-depletion experiments. Removal of cells from the BCG-primed cell populations using carbonyl iron or adherence to plastic not only abrogated the depressed responses but revealed an underlying enhancement of the immune response. The data suggest that the suppressive cell might be a macrophage.

Animals↗
PubMed1979

Phagosome/lysosome fusion: a possible prerequisite for the enhancement of antibody responses in vitro by BCG, Mycobacterium leprae and Corynebacterium parvum.

Primary in vitro antibody responses to SRBC were suppressed in cultures prepared from the spleens of CBA mice injected i.v. 20 days previously with 10(8) liver BCG. In contrast, cultures prepared from mice injected with dead BCG showed enhanced responses. In vitro spleen cell responses of the mice had returned to normal levels 4--6 weeks after their injection, but if dead BCG, M. leprae or C. parvum was added to the cultures, responses were enhanced. The enhancing effect of the added bacteria could be removed by adding also suramin, a drug known to inhibit in vitro fusion of lysosomes with phagosomes. It is suggested that the different in vivo effects of live and dead BCG may relate to differences in their handling by macrophages and more especially that the enhanced antibody forming cell response seen in the restimulated cultures of spleen cells from BCG primed mice, depends upon efficient intracellular fusion of lysosomes with the phagosomes containing the added dead bacteria.

Adjuvants, Immunologic↗
PubMed1979

Suppressed or enhanced antibody responses in vitro after BCG treatment of mice: importance of BCG viability.

Mycobacterium bovis, BCG, is known to be capable of either enhancing or suppressing various immune responses. Using a standard technique and number of organisms, some of the parameters predetermining whether enhancement or supression will occur have been investigated. Dead BCG given intravenously into mice caused an enhancement of the antibody response in vitro to sheep erythrocytes. In contrast, the same number of viable organisms caused suppression if given intravenously but enhancement if given subcutaneously. The inclusion of 25% or more killed organisms in an intravenous inoculum of fully viable organisms changed suppression to enhancement. Treatment of BCG infected mice with streptomycin lessened the suppression but did not change it to enhancement. The possible causes of suppression are discussed.

Animals↗
PubMed1977

The adjuvant effect of Corynebacterium parvum: T-cell dependence of macrophage activation.

Splenic and peritoneal macrophages from mice treated with Corynebacterium parvum enhanced the antibody response in vitro of normal nonadherent spleen cells to SRBC, but not to DNP-POL. This enhancement was dependent on the dose and time of administration of C. parvum and could be abrogated by pretreatment with carrageenan. Macrophages from T-cell-depleted mice failed to enhance the response, but this ability was restored if the mice had been reconstituted with purified T lymphocytes. Macrophages that are activated by C. parvum are a resident nondividing population. It is postulated that activated macrophages, capable of enhancing antibody responses to T-cell-dependent antigens, arise through a cell-mediated reaction to C. parvum.

Adjuvants, Immunologic↗
PubMed1977

Antibody response in vitro of spleen cells from Plasmodium yoelii-infected mice.

The primary antibody response to sheep erythrocytes and dinitrophenylated Ficoll of spleen cells from mice infected with Plasmodium yoelii was studied in vitro. The response to sheep erythrocytes was enhanced between 2 and 4 days after infection and depressed at later intervals. Cell fractionation experiments carried out at the time of immunosuppression indicated a defect of macrophage function. At the same time the response to dinitrophenylated Ficoll was normal.

Animals↗
PubMed1977

Enhancement of the antibody response in vitro by adherent cells from mice infected with Mycobacterium lepraemurium.

Spleen cells from mice systemically infected 4 to 6 weeks previously with Mycobacterium lepraemurium gave an enhanced primary antibody response in vitro to sheep erythrocytes, but responded normally to dinitrophenylated polyumerized flagellin. The ability to enhance the response was associated with the glass-adherent spleen cell population and with peritoneal cells. Similar cells obtained from infected mice depleted of T lymphocytes failed to enhance the antibody response. These studies suggest that macrophages that became activated during the development of cell-mediated immunity to infection can also stimulate antibody responses to thymus-dependent antigens.

Animals↗
PubMed1977

A re-evaluation of the role of macrophages in carrageenan-induced immunosuppression.

Administration of a single dose of 1 mg carrageenan to mice cause a temporary blockade of hepatic phagocytosis of 51Cr-labelled sheep erythrocytes (SRBC) and a prolonged reduction in the number of splenic plaque-forming cells (PFC) against SRBC. The in vitro responses to phytohaemagglutinin (PHA) and SRBC were also suppressed, whereas the response to the T cell-independent antigen DNP-Ficoll was not affected. Other in vitro experiments have shown that responses of normal cells can be actively suppressed by macrophages from carrageenan-treated mice and the possible mechanisms of this suppression are discussed.

Animals↗
PubMed1976

The role of macrophages in the adjuvant effect on antibody production of Corynebacterium parvum.

Spleen cells from mice pre-treated with C. parvum gave an enhanced in vitro antibody response to SRBC, but not to DNP-POL. This enhancing activity was associated with the adherent, but not the non-adherent spleen cell population and was found to be radioresistant. It is concluded that macrophages are directly involved in the adjuvant effect of C. parvum and the possible mechanisms of action are discussed.

Adjuvants, Immunologic↗
PubMed1975

Effects of oestrogens and pregnancy on the distribution of sheep erythrocytes and the antibody response in mice.

Mice pre-treated with three oestrogenic preparations showed increased hepatic and reduced splenic uptake of 51Cr-labelled sheep erythrocytes (SRBC). The anitbody response to SRBC wahe number of antibody-forming cells in the spleen parallels the amount of SRBC localizing in this organ and that both can be depressed or enhanced by appropriate pre-treatments with oestrogens or colloidal carbon. The effects of these agents are mediated through stimulation or 'blockade' of the phagocytic activity of liver macrophages. Changes in localization of SRBC in pregnant mice were similar to those found after treatment with oestrogens. These changes were, however, rather small and the antibody response of pregnant animals was not affected.

Animals↗
PubMed1975

Role of cellular proliferation in the stimulation of MPS phagocytic activity.

Administration of agents such as stilboestrol, endotoxin, C. parvum and zymosan, which enhance the phagocytic activity of the mononuclear phagocyte system, also stimulated cellular proliferation in the liver and spleen as assessed by [13H] thymidine incorporation into these organs, and by autoradiography and the number of mitoses in the liver. Sublethal whole body irradiation abolished the proliferative response to stimulation and also reduced or prevented the increase in phagocytic activity. This latter effect depended on the stimulatory agent used, dose of radiation and time of irradiation with respect to stimulation. The results indicate that cell proliferation is important for the increase in phagocytic activity after administration of C. parvum, zymosan and stilboestrol. Endotoxin, however, appears to act primarily by increasing the capacity of existing cells while at the same time causing cell proliferation. The population of cells responding to zymosan by increased phagocytic activity through proliferation was shown to be resident in the liver.

Animals↗
PubMed1975

Haematological changes and iron metabolism in rats after administration of Corynebacterium parvum.

Administration of 1-4 mg of C. parvum to rats caused a transient and mild normochromic and normocytic anaemia with reticulocytosis. There was also an immediate and marked fall of plasma iron concentration and a moderate increase of total iron binding capacity of plasma. Despite increased clearance of 59Fe from the plasma there was no significant change of the plasma iron turnover rate. At later intervals after administration of C. parvum an increased incorporation of iron into red blood cells and the spleen was observed. These changes in iron metabolism have been explained in terms of increased retention of iron in the mononuclear phagocyte system during the first few days after C. parvum and enhanced erythropoiesis at later intervals. Other haematological parameters remained normal, with the exception of the absolute number of lymphocytes, which initially fell sharply but soon returned to, and even exceeded, control levels. Liver and spleen weights increased greatly after administration of C. parvum, reaching a maximum at the end of the first week, and both these organs contained mononuclear cell infiltrates, granulomata and giant cells.

Anemia↗