摘要:

In the preceding report (3) experiments were described which suggested the occurrence of haemopoietic disorders in mice infected with the LCM virus. Immunological disorders associated with the LCM virus infections of mice are well‐known. It was considered that both haemopoietic and immunological defects might be caused by some virus‐induced interference with the stem cells in the infected mice. Attempts were therefore made to estimate the numbers and the function of stem cells in mice infected with the LCM virus. Haemopoietic colony assays were employed, and both acutely infected mice and persistent, tolerant virus carriers were examined. The findings suggested a decrease in colony‐forming stem cells in the bone marrow during the acute infection. However, the most striking observation in the acutely infected mice was of a profound inhibition of the colony‐forming response of stem cells in these animals. The influences exerted upon the stem cell response seemed to be quite specific, in that the response of immunocompetent cells was almost unimpaired when examined at the same time. The inhibition was not caused by a direct viral effect upon the stem cells, nor by any immune‐mediated damage. Experiments with the adult, persistent, tolerant virus carriers indicated that the haemopoietic colony formation was not inhibited in these mice despite a pronounced viraemia. However, their numbers of colony‐forming stem cells amounted to about fifty per cent of the normal values and seemed to agree with their relative increase in sensitivity to X‐rays. It is suggested that virus‐induced interference with the function of haemopoietic stem cells plays a central role for the tolerogen effects o

ISSN:0365-5563    

DOI:10.1111/j.0365-5563.1973.tb00011.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

A simple micro assay for testing mouse and human interferon is described. The L‐F1line of mouse lung fibroblasts and the U‐line of human amnion cells were seeded in microtrays, treated with two‐fold dilutions of 0.1 ml interferon and challenged with Vesicular Stomatitis virus. Reading was done microscopically for presence of cytopathogenic effect and macroscopically for metabolic activity indicated by colour change. Sensitivity of the test is comparable to the commonly employed plaque reduction assay and the macro infectivity inhibition test. Reproducibility of the system is satisfactory. The interferon titres are influenced by the age and density of cells, length of interferon treatment and the dose of challenge virus. Age, density and length of treatment are standardized for the test and by means of a standard slope it is possible to adjust interferon titres to a standard challenge dose. The micro system is time saving, technically simple and allows testing of extremely small volumes of test mat

ISSN:0365-5563    

DOI:10.1111/j.0365-5563.1973.tb00012.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

In order to test the hypothesis that the small increase in graft‐versus‐host (GVH) activity after immunizationin vivoagainst strong histocompatibility antigens may be due to an inhibitory effect of allo‐antibody on the cellular immune response, rat lymphocytes were sensitizedin vitrowith allogeneic lymphocytes. Peripheral lymphocytes from inbred Fischer (F) strain rats were culturedin vitroeither alone or together with (F × BN) F1 lymphocytes in conditions where humoral antibodies are not demonstrably formed. After 4 and 6 days of culture the activity of the stimulated and non‐stimulated cells was compared in a GVH assay using (F × BN) F1 and (F × AS2) F1 hybrids as hosts. The activity of thein vitrosensitized cells against (F × BN) F1 recipients after four and six days of culture was not significantly enhanced. These findings support the alternative hypothesis that a very high proportion of cells are in fact sensitive to histocompatibility antigens, even in the non‐

ISSN:0365-5563    

DOI:10.1111/j.0365-5563.1973.tb00013.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Blood grouping of a 65‐year‐old woman showed a normal A1antigen and in addition a weak B character, producing mixed field agglutination in anti‐B sera. In her serum B and A substances were demonstrated and an anti‐BH antibody was found. In the small family investigated, proposita was the only one who carried the abnormal blood group. It is discussed whether the blood group variant is due to inheritance of a defective B gene or to the effect of a recessive suppress

ISSN:0365-5563    

DOI:10.1111/j.0365-5563.1973.tb00014.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

The fine structure ofAeromonas liquefaciensandAeromonas salmonicidagrown in enriched and minimal media was examined by electron microscopy. When the organisms were grown aerobically, a larger amount of particles of high electron density was found than compared with cultivation under anaerobic condition. These particles were assumed to consist of melanin type of pigments. The cell wall, which was shown to consist of a distinct triple layered membrane is separated from a more indistinct triple layered cytoplasmic membrane by a relatively electron‐transparent periplasmic space of variable thickness. Channels may occur through the cell envelope, and the possible role of these channels in secretory functions of the cell is discussed. Some large inclusions of low electron density which appeared in the cytoplasma are associated with storage products of the cel

ISSN:0365-5563    

DOI:10.1111/j.0365-5563.1973.tb00015.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

The bactericidal effect of cattle normal serum onSalmonella typhimurium395 MRO is inhibited by highly avid rabbit anti‐LPS (lipopolysaccharide) IgG. Since the inhibitory effect was destroyed by pepsin, blocking of antigenic receptors on the bacterial surface by IgG is not the sole mechanism of inhibition. Furthermore, bactericidal activity was interrupted by high concentrations of anti‐RO serum as late as after 20 min, and the inhibition was independent of the bacterial concentration, at least over a range of 2 times 103– 2 times 108bact./ml, which leads to the following hypothesis: Anti‐LPS IgG bound to the bacterial surface activates the complement system without causing cell death but consumption of complement factors required for the slower bactericidal activity of norma

ISSN:0365-5563    

DOI:10.1111/j.0365-5563.1973.tb00016.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Mouse P‐388 cells were grown in suspension culture and given a short treatment with 0.5μg/ml of mitomycin C. The effects of the pyrimidine analogue caffeine on cell growth, DNA synthesis and DNA degradation in such mitomycin C treated cultures was then investigated. Post‐treatment incubation with 5·10‐4M of caffeine strongly potentiated the cytotoxic effect of mitomycin C. Exposure to the antibiotic for 1 hour inhibited cell growth only during the first day after treatment. In contrast, when these cells were incubated in medium containing caffeine, cell multiplication was suppressed during the whole experimental period. Low concentrations of caffeine prevented mitomycin C‐induced inhibition of the incorporation of thymidine into DNA. Maximum stimulation of3H‐TdR incorporation in mitomycin C treated cells was found in cultures supplemented with 5·10‐4M of caffeine. Cells labelled with3H‐TdR prior to treatment with mitomycin C did not release significant amounts of radioactivity to the culture medium. Post‐treatment incubation with caffeine did not c

ISSN:0365-5563    

DOI:10.1111/j.0365-5563.1973.tb00017.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AllEscherichia coliO antigen test strains were examined by immunoelectrophoresis in homologous O and OK sera. The immunoelectropherograms could be subdivided into few well defined groups according to the movement of the O antigen and of the thermostable polysaccharide K antigen, if present. The outcome of the examination confirmed a previous suggestion that only a limited number of test strains have a special polysaccharide K antigen. The previously indicated relationship between pathogenicity and immunoelectrophoretic pattern was emphasized.

ISSN:0365-5563    

DOI:10.1111/j.0365-5563.1973.tb00018.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Morphological variants of fourMoraxella bovisstrains were studied, using different cultural conditions. On bovine blood agar medium two colony types could be distinguished: 1) large, flat, rough and agar‐corroding, and 2) most often smaller, convex, smooth and non‐corroding forms. When transferred to human blood agar, the flat type formed convex, spreading‐corroding colonies (SC type) and the other type remained convex, non‐spreading and non‐corroding (N type). Some cell lines lost the original flat colony appearance on bovine blood agar after passages for a longer period on human blood agar; on bovine blood agar these SC cells now formed convex, but still corroding colonies. By electron microscopy it was observed that cells from corroding colonies on either medium were strongly fimbriated, whereas preparations from non‐corroding populations had non‐fimbriated cells or contained only an occasional fimbria. Conjunctival infection experiments in calves revealed that only fimbriated variants of each strain were able to colonize the conjunctival mucosa. Ultraviolet irradiation of the eye prior to inoculation facilitated the bacterial colonization, with respect to initiation and duration. Non‐fimbriatedM. boviscould not be reisolated even after irradiation. Keratitis and conjunctivitis only occurred in irradiated eyes inoculated with cell lines yielding typically flat, corroding colonies on bovine blood agar. The possible function of fimbriae for attachment ofM. bovisto the mucous membranes of the e

ISSN:0365-5563    

DOI:10.1111/j.0365-5563.1973.tb00019.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Thirteen strains, or clones, of oxidase positive, rodshaped bacteria from the human pharynx and a perimandibular abscess were identified asNeisseria elongataby comparison with the type strain of this species in conventional cultural and biochemical tests and in genetic transformation. The study establishesN. elongataas an entity of more than sporadic occurrence in pharyngeal cultures.

ISSN:0365-5563    

DOI:10.1111/j.0365-5563.1973.tb00020.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY