Search PubMed⌕ Search

Biomedical subjects

H Hof

Publications and source records attributed to H Hof.

At least 181 records · Page 10Linked to original sources

[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↗

[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↗

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↗

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↗

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↗

[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↗

[Vitamin A, the "anti-infective" vitamin? (author's transl)].

Severe vitamin A deficiency undoubtedly leads to increased susceptibility to infection. On the one hand this is due to the mucosae being damaged by the vitamin deficiency to the extent that these natural barriers are more easily overcome by pathogens. On the other hand, however, also the general defensive condition is weakened, which is partly attributable to a decrease in lymphatic tissue. An increased supply of vitamin A may possibly intensify the production of antibodies, but a definitely positive effect on the course of infections is not established. Therefore, the characterization of vitamin A as "anti-infective" is justified to some extent only.

Animals↗

Morphology and time course of experimental listeriosis in nude mice.

Experimental listeriosis in phenotypically normal (nu/+) euthymic NMRI mice has a characteristic morphology and short-term course. In contrast, listeric infection in congenitally dysthymic nude (nu/nu) mice does not proceed in clear-cut phases, develops more slowly, displays a chronic tendency from the beginning, and shows a considerably different morphology. The inability of nude mice to effectively control and terminate infection by Listeria monocytogenes obviously results from the lack of T lymphocytes.

Animals↗

Macrophage function and host resistance against infection with Toxoplasma gondii.

The role of macrophages on the course of an infection with Toxoplasma gondii has been examined. Stimulation of macrophage function by killed Bordetella pertussis cells did not show any beneficial effect as an increased susceptibility became apparent. The functional blockade of macrophages by dextran sulfate or carbon particles did not result in a higher susceptibility of mice to the lethal primary infection with T. gondii. Thus in vivo macrophages apparently do not play an essential role as effector cells as they do in infections with other obligate intracellular infective organisms such as Listeria monocytogenes. The spleen is apparently of crucial importance for resistance against T. gondii infection, since death occurred earlier in splenectomized mice than in control animals.

Animals↗

Effectiveness of orally administered Bordetella pertussis vaccine in mice.

Oral administration of killed Bordetella pertussis organisms to mice results in increased resistance to an intracerebral infection with virulent B. pertussis cells. The rate of survival is dependent on the dose of antigen. But besides specific systemic immunity, which is persistent over a long period, also transient non-specific resistance is increased. These effects are evidently induced without penetration of bacterial substances into the circulation.

Administration, Oral↗

Preparation and properties of concanavalin A-binding glycopeptides derived from rat brain glycoproteins.

Mannose-rich glycopeptides derived from brain glycoproteins were recovered by affinity chromatography on Concanavalin A-Sepharose. These glycopeptides, which adsorb to the lectin and are eluted with alpha-methylmannoside, constitute about 25--30% of the total glycopeptide material recovered from rat brain glycoproteins. They contain predominately mannose and N-acetylglucosamine (mannose/N-acetylglucosamine = 3), as well as small amounts of galactose and fucose. Approx. 65% of the Concanavalin A-binding glycopeptide carbohydrate was recovered after treatment with leucine aminopeptidase, gel filtration on Biogel P-4, and ion-exchange chromatography on coupled Dowex 50-hydrogen and Dowex 1-chloride columns. The purified glycopeptide fraction contained six mannose and two N-acetylglucosamine residues per aspartic acid and possessed an apparent molecular weight of about 2000 as assessed by gel filtration and amino acid analysis. Galactose and fucose were absent. Treatment of the purified glycopeptides with alpha-mannosidase drastically reduced their affinity for Concanavalin A, suggesting the presence of one or more terminal mannose residues.

Amino Acids↗

Studies on the immunizing capacity of orally administered particulate antigens. II. Production of immunological memory in germ-free mice by orally administered sheep erythrocytes.

A study was perfromed to find out, whether or not the oral administration of sheep erythrocytes results in a general primary immune reaction as well as in effective priming for the secondary response in both conventional and germ-free NMRI mice. Whereas negative results were obtained with conventionally held mice, five oral applications of 0.3 ml of a 60% suspension of sheep erythrocytes to germ-free mice, each dose separated by an interval of 24 hr, resulted in a general primary immune response both at the cellular and humoral levels. When such pretreated mice were given an i.p. injection of 4 times 10(8) sheep erythrocytes as a secondary antigenic stimulus 32 days after the last of the five oral applications, the subsequent response was characterized by the predominant development of 7S hemolysin-producing spleen cells. This evidently indicates that effective priming for the secondary response has taken place by the orally administered antigen.

Administration, Oral↗

[Tetanus immunity during senescence (author's transl)].

The circulating concentrations of antibodies directed against tetanus toxoid were determined by means of the mouse protection test in the serum samples of 2554 patients with an age between 60 and 98 years. Additionally, a part of the sera was tested by a radioimmunologic procedure. Immunity (neutralizing antitoxin titer greater than or equal to 0.01 International Units/ml serum) was only demonstrable in a small percent of the samples (15.3%). Compared to women, a larger percentage of men were found to be protected. Active immunization of aged persons (60-93 years old) resulted in the finding that usually also during senescence powerful immunity may develop following suitable vaccination.

Aged↗