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Biomedical subjects

P Emmerling

Publications and source records attributed to P Emmerling.

At least 19 recordsLinked to original sources
PubMed1988

Histomorphology of experimental listeriosis.

This paper is a survey of the histomorphology of experimental listeriosis based on cooperative studies performed within the past ten years. The influence of various parameters of the infectious agent (pathogenic Listeria monocytogenes serovar 4b, nonpathogenic Listeria innocua serovar 6b etc.) as well as of the host (euthymic NMRI-mice conditioned with dextran sulfate 500 or cyclosporin A, athymic nude mice etc.) on the course, morphology and outcome of the Listeria infection was investigated. From the experimental models used and the studies performed much could be learned concerning the factors that determine the histomorphological manifestations of listeriosis in humans.

Animals↗
PubMed1988

Alteration of non-specific resistance to infection with Listeria monocytogenes.

The experimental infection of murine hosts with Listeria monocytogenes is often used as a model for cell-mediated immunity. However, the natural immunity or non-specific resistance to listeriosis can be influenced by the parasite itself and also by a wide array of endogenous and exogenous host factors. The most important host factor in inbred mouse strains is their genetically determined susceptibility or resistance to Listeria monocytogenes. Secondly, the age of the mice is crucial for the outcome of infection. Resistance is only slowly developed by newborn mice, while aged mice possess an increased non-specific resistance as compared to young adult animals. Resistance is further influenced by the nutritional status, by pregnancy or by a simultaneous second antigenic stimulation. Regarding exogenous factors, macrophage blocking agents can totally abolish the resistance to listeriosis, while a lot of immunomodulating agents, such as BCG, killed Bordetella pertussis or Propionibacterium acnes organisms, lipopolysaccharides, suramin etc., can either increase or decrease the resistance. The mononuclear phagocyte system seems to be the main target of all these immunomodifiers. The timing between listeria infection and application of the immunomodulator determines the effect on non-specific resistance. A simultaneous injection of parasite and immunomodulator results in a decrease of resistance, while the application of immunoadjuvants several days before infection can dramatically increase the resistance to listeriosis. The delicate equilibrium of the mononuclear phagocyte system must therefore be taken into account, when infection with Listeria monocytogenes is used to test for immune-modifying agents, which are intended for use in humans or animals.

Adjuvants, Immunologic↗
PubMed1984

Murine model for therapy of listeriosis in the compromised host. III. The effect of rifampicin.

10 different strains of Listeria monocytogenes tested in vitro were found to be susceptible to rifampicin showing minimal inhibitory concentrations between 0.0075 and 0.06 microgram/ml. Mice infected with a virulent strain of L. monocytogenes were treated with this antibiotic. Bacterial counts rapidly declined. In dextran sulfate-treated animals, deprived of their macrophage system and consequently highly susceptible to Listeria infection, rifampicin was able to protect the animals. Furthermore, nude athymic mice, chronically infected with L. monocytogenes, were also nearly cured. A few remaining bacteria, however, started to multiply after cessation of therapy, so that a relapse was noted. Development of resistance of L. monocytogenes to rifampicin during treatment was not observed.

Animals↗
PubMed1983

[Evaluation of a new latex agglutination test for identification of staphylococcus aureus].

286 clinical isolates of staphylococci and 19 Micrococcus spp. were tested in a new latex agglutinating test to detect bound coagulase and protein A simultaneously. Coagulase-positive strains of staphylococci (n = 119) were all found to be latex-positive. Negative latex agglutination test results were obtained with 154 out of 167 coagulase-negative strains, the other 13 (7.8%) strains gave positive latex tests. Furthermore 3 out of 19 Micrococcus strains yielded positive agglutinating results. According to the results presented a negative latex test allows a rapid exclusion of S. aureus. A positive latex test requires the determination of further typical characteristics to differentiate among the staphylococcal isolates.

Bacterial Infections↗
PubMed1982

Macrophage function in senescence.

Although the parenteral injection of dextran sulfate 500 (DS 500; 50 mg/kg body weight) into 22-month-old NMRI mice resulted in a complete loss of resistance when administered 1 day before the sublethal (4.5 X 10(3)) infection with Listeria monocytogenes, the consequences in aged animals were less dramatic than in young adult (2- to 3-month-old) controls. This was documented by prolonged survival times as well as reduced numbers of Listeriae in spleen. This indicates that aged mice possess an increased paghocytic capacity, as compared to young adult animals. In aged mice the DS 500-induced loss of resistance could be completely abolished by pretreatment with 3 X 10(9) heat-killed Bordetella pertussis organisms 4 days before the DS 500 injection, i.e., 5 days before listeric infection. This indicates that aged NMRI mice possess remarkable reserves in phagocytic activity.

Aging↗
PubMed1981

Biological activity of Bordetella pertussis in lipopolysaccharide-resistant mice.

Effects of Bordetella pertussis organisms, such as adjuvanticity, induction of hypersplenia, and leukocytosis as well as modification of nonspecific resistance to infection and typical morphological response of lymphatic organs, were studied in the lipopolysaccharide-resistant C3H/HeJ mouse strain. It was shown that B. pertussis exerted all of these effects in C3H/HeJ mice, although the morphological response, hypersplenia, and modification of resistance to infection with Listeria monocytogenes in such animals were less pronounced than those in lipopolysaccharide-sensitive mouse strains. This indicated that the biological activity of B. pertussis as determined in the present studies, is due partly to structural components other than lipopolysaccharide.

Adjuvants, Immunologic↗
PubMed1981

Murine model for therapy of listeriosis in the compromised host. I. Effect of ampicillin.

Therapy of listeriosis with ampicillin was examined in two murine models with compromised defense mechanisms. In mice treated with dextran sulfate paralysing the function of the macrophage system, ampicillin was less able to reduce death rates as well as bacterial counts in the spleens than after infection of normal mice. In nude mice with chronic listeriosis, treatment with ampicillin was started 8 days after infection. The numbers of viable listeria cells decreased under therapy, but a bacteriologic cure was not achieved in a 6-day schedule. Relapse followed cessation of therapy.

Ampicillin↗
PubMed1979

Age-related defense against infection with intracellular pathogens.

Young adult (6--12 weeks old) and aged (20--24 months old) NMRI mice were infected with various intracellular parasites. The following results were obtained: (1) After a sublethal infection with Listeria monocytogenes, aged mice were found to show a resistance similar to that of young adults. A challenge infection with this pathogen was followed by specific immunity of long duration in both age-groups. (2) On the other hand, young animals were significantly more resistant to Salmonella typhimurium than aged mice. It was concluded that this was due to the LD50 which was 14 times greater for 2-month-old than for 20-month-old mice. Furthermore, during 7 weeks after infection there were more S. typhimurium in the spleens of senescent mice than in those of young adult controls. (3) Aged mice showed highly increased susceptibility to the weakly virulent DX strain of Toxoplasma gondii. Almost all aged animals died whereas the control mice survived. When death of the aged mice was prevented by treatment with sulfadiazine after infection with the DX strain, the aged mice were found to be as well protected against subsequent infection with the strongly virulent BK strains as the young adult mice. These results suggest that the susceptibility of the aged animal to infectious agents may considerably vary from one pathogen to another.

Aging↗
PubMed1978

Reversion of dextran sulfate-induced loss of antibacterial resistance by Bordetella pertussis.

Parenteral injection of dextran sulfate 500 (DS 500; 50 mg/kg of body weight) into mice caused a complete loss of resistance to a sublethal (2 X 10(3) to 5 X 10(3)) infection with Listeria monocytogenes. Such loss could be prevented by pretreatment of animals with 3 X 10(9) heat-killed Bordetella pertussis organisms (PO) 5 to 30 days before the administration of DS 500. The increased phagocytic capcity induced by PO was only exhausted when a fourfold dose of DS 500, effecting complete loss of antibacterial resistance (50 mg/kg ob body weight), was administered. Listeriosis in mice treated with DS 500 is characterized by rapid-progressive necro-purulent inflammation of liver and spleen, lack of mononuclear phagocyte response, and 100% lethality within 72 h after infection. In contrast, the time course, extent, and morphological characteristics of listeriosis in animals pretreated with PO before the DS 500 application were not significantly different from those of nonpretreated controls. Evidence is presented that the protective effect of PO is due to activation of the mononuclear phagocyte system, which without such treatment is blocked by the DS 500 administration. The data presented indicate that the protective effect of PO is due only in part to the endotoxic moiety of these bacteria. Differences in the course and morphology of listeriosis in animals with dysfunction of the mononuclear phagocyte system and in animals with deficiency of the cellular immune system are discussed.

Adjuvants, Immunologic↗
PubMed1978

Postnatal development of resistance against infection in an experimental model.

The postnatal development of resistance against infection was monitored by the treatment of juvenile mice with a virulent strain of Listeria monocytogenes. It could be shown that until day 10 after birth, young mice succumbed to an infection with even minimal doses of bacteria. Between day 15 and 30, the resistance against infection gradually increases until the rather constant level of grown-up animals is reached (Fig. 1). Juvenile mice that survive the primary infection are able to build up a state of immunity, which is rather similar to that of grown-up mice (Fig 3). Immunity against L. monocytogenes is mainly expressed by a functionally active T-cell system; the maturity of these cells in 15 days old mice could be demonstrated by the transfer of cells to "nude"-mice, which lack a thymus (Fig. 4). A significant increase of the non-specific resistance can be achieved even in 10 days old mice by the injection of adjuvants like pertussis organisms or endotoxin of Salmonella typhi some days before infection (Fig. 5, Fig. 6). Our findings suggest that a deficiency of functionally active macrophages is responsible for the insufficient resistance against infection with L. monocytogenes in young mice.

Animals↗
PubMed1978

[Influence of killed Bordetella pertussis cells on the resistance against infection with Listeria monocytogenes (author's transl)].

The influence of killed Bordetella pertussis cells (B.p.) on the cell-mediated resistance of mice against infection with virulent germs of Listeria monocytogenes has been studied. Resistance of mice was decreased, when 3 X 10(9) B.p. were injected 1 day before, simultaneously with or 1 day after infection, resulting in augmented amounts of viable Listeriae recovered from the spleens 3 days after infection (figure 1). The LD50 was strongly reduced (Table 1). Transfer of immune spleen cells to recipient mice, which had been treated 1 day previously with 3 X 10(9)B.p., did not support resistance definitely (Table 2). Therefore, it can be concluded that probably the macrophage system was impaired just after B.p. injection. When, however, B.p. were given several days before infection, resistance was increased. A maximum of resistance enhancement was seen 7-14 days after B.p. treatment. Thereafter, this beneficial effect gradually decreased but persisted for at least 67 days (figure 1). This resistance enhancing effect of B.p. was surely not due to adjuvant effect of B.p. on the T-lymphocyte-mediated immune reaction to Listeriae, since in B.p.-pretreated mice the development of immunity during the primary infection to a secondary listeric infection has even been lacking (Table 3). It is more likely that the macrophage system was stimulated at this time by B.p. In mice treated 7 days prior to infection the elimination of Listeriae from the spleens was supported from the very beginning of the infection (figure 2).

Adjuvants, Immunologic↗
PubMed1978

[Resistance to infection with Listeria monocytogenes in normal and thymusless mice treated with ampicillin (author's transl)].

NMRI mice were infected intravenously with a sublethal dose of Listeria monocytogenes and divided into four groups. One group served as the control and the other three were treated with ampicillin beginning 4, 8 or 24 hours after infection. The animals were injected in the morning and in the evening each time with 4 mg ampicillin subcutaneously until a total dose of 48 mg was reached. As demonstrated by counting of the bacteria in the spleen, Listeria could multiply in the ampicillin treated mice in comparison to the control group at best delayed but the infection continued to persist for some days at a level of 10(3)-10(4) Listeriae per spleen independent from the starting point of the treatment. Eight days after the first infection all animals received a challenge dose of 10(4) Listeriae. Compared with the control animals the ampicillin treated mice had a clearly reduced immunity, even in the group in which ampicillin application had been started 24 hours after the primary infection. If the challenge infection was given at first after an intervall of six weeks between primary and secondary infection, only a reduced immunity was found. Furthermore, whereas spleen cells of mice 7 days after infection were able to transfer immunity to untreated recipients, spleen cells of ampicillin treated mice were unable to do so. Finally, an attempt was made to cure chronic listeric infection in thymusless nude mice by the application of high doses of ampicillin. The observation of a continuous infection in these animals showed that the T-cells played a primary importance in the elimination of the bacteria.

Ampicillin↗
PubMed1977

Suppression of the secondary immune response by specific antibody, when given together with the secondary antigenic stimulus.

It is generally believed that antibody-mediated immunosuppression can be only produced in non-primed individuals, and that this applies both to experimental animals and Rh-negative women at risk. However, in this paper it is reported that the additional injection of 0.2 ml of an antiserum to sheep erythrocytes (SE) together with a secondary antigenic stimulus of 10(8) SE into mice, primarily immunized by a tiny dose of 5 x 10(5) SE 28 days before, was capable of producing effective suppression of the secondary immune response.

Animals↗
PubMed1977

Cell-mediated resistance to infection with Listeria monocytogenes in nude mice.

Congenitally dysthymic nude (nu/nu) NMRI mice showed increased resistance to viable Listeria monocytogenes cells during the initial phase of infection as compared with euthymic control mice. The intravenous mean lethal dose (LD50), as determined for euthymic mice after an observation time of 7 and 14 days, amounted consistently to 6 X 10(4) Listeria. The corresponding values determined in nude mice were found to be increased by either 20-fold (1.2 X 10(6) Listeria after an observation time of 7 days) or 4-fold (2.4 X 10(5) Listeria after an observation time of 14 days). The transfer of spleen cells from immune euthymic donor mice into chronically infected nude mice caused almost complete elimination of Listeria within 1 week. The injection of dextran sulfate 24 h before a secondary infection with L. monocytogenes caused loss of antibacterial resistance in both chronically infected nude mice and Listeria-immune euthymic mice, this being expressed by a rapid increase in the numbers of bacteria in the spleens as well as the occurrence of serious signs of illness.

Animals↗
PubMed1977

Antibody-forming potential of lymph nodes in aged mice, with special reference to the influence of adjuvant.

The secondary antibody-forming potential of non-splenic lymphatic tissues during senescence was investigated in NMRI/Han mice, both at the cellular and humoral levels. The mean life span of conventionally reared NMRI/Han mice amounts to 19.86 months. After primary immunization of aged (20-month-old) NMRI mice with 4 X 10(8) sheep erythrocytes (SE) by the intraperitoneal (i.p.) route, the primary antibody-forming potential of both spleen and lymph nodes was significantly reduced, as compared to young adult (3-month-old) controls. In contrast, the anamnestic response elicited by an i.p. booster injection of 4 X 10(8) SE at the 44th day after primary immunization was not significantly diminished in comparison to the controls. When killed cells of Bordetella pertussis were found to be significantly increased in young adult as well as in aged mice. These data obtained at the cellular level were in accordance with corresponding serological findings. The impressive restitution of the antibody-forming potential evident after secondary antigenic stimulation was associated with a remarkable restitution of the lymph node morphology. This was particularly pronounced in the pronounced in the parathymic lymph nodes which represent the draining nodes for the peritoneal cavity. These findings indicate that the lymph nodes of the senescent individual also possess remarkable reserves in immunocompetence.

Adjuvants, Immunologic↗
PubMed1977

[Influence of latent vitamin A deficiency of the mouse on the production of humoral antibodies against sheep erythrocytes and on the resistance against infection with Listeria monocytogenes (author's transl)].

Mice fed with a vitamin A free diet for several months did not develop signs of vitamin A deficiency. However, chemical analysis revealed a reduced content of vitamin A in the liver of such mice. The ability of these animals were latent vitamin A deficiency to produce antibodies against parenterally applicated sheep erythrocytes was not hampered. Similar numbers of antibody producing cells could be detected in the spleen of these mice compared with control animals. Resistance against intravenous infection with L. monocytogenes of these mice with latent vitamin A deficiency was not altered. The numbers of viable germs recovered from spleen and liver 2 days after infection were similar in both vitamin A deprived and normal mice.

Animals↗