Effect of Bacillus Calmette-Guérin infection on delayed footpad reaction to Listeria monocytogenes

The role of peritoneal macrophages induced by Bacillus Calmette-Guérin (BCG) in the induction of immune responses to Listeria monocytogenes was studied in mice. The peritoneal macrophages from mice treated with BCG 14 days previously contained a high proportion of Ia-bearing macrophages (approximately 56%) and the cells showed not only a high level of listericidal activity but also a strong ability for presentation of listerial antigen to Listeria-immune T cells. An intraperitoneal inoculation with a low dose of Listeria, which can induce the maximal level of delayed footpad reaction (DFR) and positive migration inhibitory activity of macrophages in untreated mice, did not induce a detectable level of such responses in BCG-treated mice. The bacterial growth at an early stage of infection was suppressed by scavenger macrophages in these mice. On the other hand, BCG-treated mice showed the early development of DFR and macrophage migration inhibitory activity after an inoculation with a high dose of Listeria. It is revealed in transfer experiments that Listeria-pulsed peritoneal exudate cells induced by BCG elicited the highest level of DFR and positive migration inhibition of macrophages in normal mice at the earlier period of injection compared with Listeria-pulsed resident peritoneal cells. These results suggested that the increased activities of macrophages acting as scavenger cells and as antigen-presenting cells play important roles in the modification of immune responses to Listeria in BCG-treated mice.     

Immunochemical properties of immunoglobulin G conjugated with dextran

Antigen-binding activity and effector functions of immunoglobulin G from horse and rabbit sera have been investigated, using hemagglutination, kinetic immune lysis, immune lysis in microplates and rosette-forming test with peritoneal mononuclear cells of mice, after their conjugation with dextran, MW 35-50 kD. The formation of conjugates of two types has been demonstrated: protein-dextran and protein-dextran-protein. It has been revealed that protein-dextran-protein conjugates have high specific antigen-binding activity, as compared to native IgG from rabbit sera specific for SRBC, while interactions with the complement system and Fc receptors is depressed.     

Information value of the indices of the nonspecific resistance of the body

A number of nonspecific resistance characteristics in mice, such as the total number of peritoneal exudate cells, the percentage and absolute number of macrophages, their cytochemical activity in the spontaneous tetrazolium test and cytochemical capacity, have been studied by comparison with the resistance of the animals to tularemia infection induced by Francisella tularensis, Ga?ski?'s vaccinal strain 15. Of these characteristics, the cytochemical capacity of peritoneal exudate macrophages, i.e. the total cytochemical activity of macrophages contained in a unit of volume, has been the most informative as regards the level of nonspecific resistance to this infection. Other characteristics under study cannot serve as criteria for the evaluation of the nonspecific resistance of the body to F. tularensis.     

Control of syngeneic tumor growth by activation of CD8+ T cells: efficacy is limited by migration away from the site and induction of nonresponsiveness

Activation of Ag-specific CD8+ T cells in response to syngeneic tumor has been visualized by adoptive transfer of CD8+ T cells from OT-I mice, with a transgenic TCR specific for H-2Kb and an OVA peptide, into Thy-1 congenic recipients. Intraperitoneal challenge with E.G7, the EL-4 thymoma transfected with OVA, results in activation and clonal expansion of the OT-I cells in the peritoneal cavity and transient control of tumor growth. However, within 2 days after becoming activated, the OT-I cells migrate out of the peritoneal cavity into the spleen and lymph nodes, and tumor growth resumes in the peritoneal cavity. The OT-I cells in lymph nodes and spleen have lytic effector activity, but exhibit split anergy in that they cannot proliferate in response to Ag unless exogenous IL-2 is provided. The failure to remain at the tumor site and continue to control tumor growth is not due to selection of Ag loss variants or development of suppression. These results suggest that effective CD8-targeted immunotherapy may depend less on enhancing the initial activation and more on sustaining the response at the appropriate location and/or reactivating cells that have left the site of tumor growth and become nonresponsive.     

The dependence of the functional activity of "immune" macrophages on T-cells

The dependence of the functional activity of the peritoneal macrophages of mice immunized with Francisella tularensis vaccine strain on the presence of T-cells in the culture has been studied. The elimination of "immune" macrophages and sensitized T-lymphocytes by means of anti-Thy-1-2-serum has been shown to lead to a sharp decrease in both ingestive and digestive functions of the phagocytic mononuclears of peritoneal exudate to the level of the activity of macrophages isolated from intact animals.     

Effect of pertussis vaccine on the functional activity of the peritoneal and splenic macrophages in 2 mouse strains genetically differing by the intensity of their immune response

The immunostimulating effect of corpuscular pertussis vaccine on the antigen-presenting and bactericidal functions of peritoneal and splenic macrophages in CBA and C57BL/6 mice, differing in the intensity of immune response to sheep red blood cells and Salmonella typhimurium, has been studied. The study has revealed that the injection of pertussis vaccine alters the functional activity of the cells under study, the effect depending on the immunizing dose, the strain of mice and the time elapsed from the moment of immunization. Pertussis vaccine enhances the low capacity of macrophages for antigen presentation in C57BL/6 mice with low responsiveness and alters the resistance of peritoneal and splenic macrophages to the cytopathic action of salmonellae.     

Effect of microenvironment on functional activity of murine B-lymphocytes

In contrast to B-splenocytes, murine peritoneal B-cells do not produce or secrete immunoglobulins (Ig). Twenty-four hours after intraperitoneal transfer of splenocytes containing Ig-forming cells (IFC), IFC content in the peritoneal cavity of recipient mice decreases dramatically. This decrease does not depend on the migration of transferred IFC to the spleen (homing); splenectomy has no effect on this process. In order to check whether the lack of IFC in the peritoneal cavity is due to inhibition of synthesis or secretion of Ig, peritoneal cells (contained 4360 IFC/10⁶ cells) of CBA mice were intraperitoneally transferred to CBA/N mice after a 4-day preincubation in vitro. On the next day, ～30% of in vitro transferred IFC were detected in the peritoneal cavity of recipient mice, but on day 4 the IFC content in peritoneum returned to the background level. Repeated in vitro incubation of peritoneal cells of recipient mice restored the IFC number in cultured cells. It means that peritoneal microenvironment inhibits functional activity of murine B-lymphocytes.     

Suppressing action of splenic cells on macrophage phagocytic activity]

The culture media withdrawn from 18-hour cultures of live spleen cells suppressed the phagocytic activity of peritoneal macrophages in mice. The level of suppression, as estimated for an equal number of spleen cells, varied in individual animals, which seemed to be connected with the level of normal infection in the animals. In the process of development of Ehrlich's carcinoma in mice suppressors were produced in the spleen in an increased amount, but only in connection with the total increase in the number of spleen cells, and not due to the selective accumulation of suppressor cells.     

Cytotoxic T cells in the peritoneal cavity of mice infected with ectromelia virus.

Peritoneal exudate cells from mice infected with ectromelia virus were cytotoxic for virus-infected target cells as measured in a 51Cr release assay. Cytotoxic activity seemed to be T cell-dependent as it was largely abolished by treatment with anti-theta serum and complement but was not impaired by macrophage depletion. The kinetics of development of cytotoxicity in the peritoneal cavity lagged behind spleen cytotoxicity by 1-2 days. Peak activity in peritoneal cells was present about 6 days after intravenous infection with virus. These studies suggest that macrophages present in the free peritoneal cell populations of ectromelia-infected mice are not cytotoxic for virus-infected target cells. The effect of macrophages in virus clearance is therefore likely to be due to phagocytic rather than cytotoxic effects.     

The effect of somatic antigen from Bacillus subtilis on migration of mouse macrophages]

The migration of mice peritoneal macrophages has been studied on agar plates. The migration of the macrophages from mice treated by the intra peritoneal route by a somatic antigen of Bacillus subtilis, was 37% less than the migration of the macrophage from control mice. The presence of the antigen in the gel did not modify the migration of macrophages in either treated or control mice. This confirms the non specific character of the activity of this antigen.     

Antigenic Determinants of Salmonella for Production of “Clearance” Factor in Mouse Typhoid

The “clearance” factor produced in the peritoneal cavity of mice immunized with killed vaccines prepared from Salmonella typhimurium or S. enteritidis was identified as the specific antibodies elicited by the O side chain of the cell wall polysaccharides in the organisms used as immunogens. After immunization of mice with vaccines prepared from virulent Salmonella strains, complement-dependent antibacterial antibodies in the serum and “clearance” factors in the peritoneal cavity were found to appear coincidentally, to last for more than one year, and to have the same specificity against the virulent bacterial strains. The relationship between the complement-dependent antibacterial antibodies and “clearance” factor, and the mechanisms of bactericidal action of these antibacterial agents in experimental typhoid were discussed.     

Macrophage activation induced by a synthetic antioxidant

The effect of a synthetic antioxidant 2-tretbutyl-3-hydroxypyridine (TBHP) on the function of murine peritoneal macrophages (MP) has been studied. A direct contact of TBHP with MP in vitro increased the activity of a key enzyme of glucose monophosphate graft--glucose-6-phosphate dehydrogenase and the proportion of flattened MP. as compared to the control. Upon intraperitoneal MP injection the number of MP's in the abdominal cavity of mice increased. They differed from control MP's in enhanced flattening and phagocytosis. In mice with preinduced defect of abdominal clearance TBHP contributed to the recovery of the normal level of antibacterial protection. In all the in vitro and in vivo tests studying its activating effect on MP, the synthetic antioxidant was not inferior to the standard MP activator--bacterial lipopolysaccharide.     

Synthesis of spontaneous interferon by mouse peritoneal cells in vitro. II. Characteristics of the process of spontaneous interferon synthesis

As it was shown previously that the peritoneal cells of mice were capable of producing interferon spontaneously. Spontaneous interferon appeared after 5 to 6 h of incubation of peritoneal cells at 26 degrees C and its highest level has been found after 12 h. The production of spontaneous interferon was inhibited by 4 h incubation of peritoneal cells at a temperature of 37 degrees C as well as by actinomycin D added at 0 to 4 h.     

Action of plant extracts on the natural immunity indices of animals

The influence of extracts from oak bark, St. John's-wort leaves and pine buds on natural immunity characteristics of mice has been studied. The injection of these extracts into mice has been found to enhance their resistance to infection with Staphylococcus aureus and Bordetella pertussis virulent cultures, to decrease the enzymatic activity of 5'-nucleotidase in the peritoneal exudate macrophages of mice and to increase the level of lysozyme in their blood. The action of these extracts has proved to depend on their dosage and the time of observation.     

Immunomodulating properties of salmozan and its effect on the functional activity of macrophages

The effect of salmozan on the resistance of mice to Listeria monocytogenes infection, the formation of delayed hypersensitivity (DH) to sheep red blood cells in the animals, as well as changes in some functional activity characteristics of macrophages have been studied. The study has revealed that salmozan enhances anti-infectious resistance, suppresses the dermal manifestations of DH, and decreases the level of 5'-nucleotidase in peritoneal macrophages, stimulating their phagocytic activity. The intensity of the drug action depends on the time of its administration. The most pronounced immunomodulating action and maximal changes in the function of macrophages have been registered simultaneously after the treatment of the animals with salmozan.     

Changes in the immunotropic activity of neutrophilokins in the course of experimental staphylococcal infection

The influence of the products secreted by activated neutrophils (neutrophilokins) of mice, both intact and infected with staphylococci, on the activity of mouse spleen cells in the graft-versus-host reaction, immune response to sheep red blood cells and the antigen-presenting function of peritoneal macrophages was studied. Neutrophilokins of intact mice stimulated the activity of immunocompetent cells. Neutrophilokins obtained from infected mice on day 3 after infection produced an immunosuppressing effect. On day 7 after infection the immunostimulating activity of neutrophils was restored and showed practically no difference from the normal level.     

Differences in iNOS and arginase expression and activity in the macrophages of rats are responsible for the resistance against T. gondii infection

Toxoplasma gondii infects humans and warm blooded animals causing devastating disease worldwide. It has long been a mystery as to why the peritoneal macrophages of rats are naturally resistant to T. gondii infection while those of mice are not. Here, we report that high expression levels and activity of inducible nitric oxide synthase (iNOS) and low levels of arginase-1 (Arg 1) activity in the peritoneal macrophages of rats are responsible for their resistance against T. gondii infection, due to high nitric oxide and low polyamines within these cells. The opposite situation was observed in the peritoneal macrophages of mice. This discovery of the opposing functions of iNOS and Arg 1 in rodent peritoneal macrophages may lead to a better understanding of the resistance mechanisms of mammals, particularly humans and livestock, against T. gondii and other intracellular pathogens.     

Antibacterial resistance induced by recombinant interleukin 1 in myelosuppressed mice: effect of treatment schedule and correlation with colony-stimulating activity in the bloodstream

We have investigated the effects of interleukin 1 (IL-1) administration on the ability of neutropenic mice to resist Pseudomonas aeruginosa challenge in vivo. Cyclophosphamide-treated mice received human rIL-1 beta at 7.0, 0.7, or 00.7 micrograms/kg, according to different regimens, to be challenged with a lethal ip inoculum of pseudomonas cells 5 days after myelosuppression. The repeated exposure of the neutropenic mice to an overall cytokine dosage of 7.0 or 0.7 micrograms/kg during the 4 days after myelosuppression was found to optimally restore the animals' antibacterial resistance. However, when administered as a single injection 24 hr before challenge, the same dosages of IL-1 had lower or no effect in enhancing survival, primarily leading only to a reduction in the amount of antipseudomonal chemotherapy required for cure. The regimen of IL-1 administration conferring optimal protection also resulted in a decrease in the number of pseudomonas cells recovered from the peritoneal cavity of infected mice. This regimen accelerated hematopoietic recovery in cyclophosphamide-treated mice. Assay of serum colony-stimulating activity (CSA) revealed that (a) cyclophosphamide treatment alone significantly increased the level of circulating CSA, (b) administration of a single dose of IL-1 to neutropenic mice induced an early, further increase in serum CSA, followed by depression, (c) a biphasic pattern of CSA response was also evident in mice repeatedly treated with IL-1. These results suggest that regulation of hematopoiesis may have an important role in the induction of antibacterial resistance in myelosuppressed hosts repeatedly treated with low dosages of IL-1.     

Complex study of the oxidative metabolism of peritoneal macrophages attached to glass

A method of obtaining a peritoneal macrophage enriched population on a slide in a special chamber has been worked out and tested. It has been shown that such cells keep specific morphological and functional peculiarities, including the ability to phagocytosis. They are in active state and can be utilized for studying the biological oxidation processes. A relative activity of oxidative metabolism of key enzymes has been evaluated. The possibility of studying the respiratory chain activity in these cells was shown by polarographic and fluorescent methods. Alternative oxygen-dependent systems were investigated. It was determined that NADPH-oxidase of peritoneal macrophages attached to a slide, responsible for "the respiratory burst" formation and defining their bactericidal properties and peroxide generating ability, is in the active state.