Conditioned medium prepared from the mouse fibroblast cell line L 929 which is known to produce colony-stimulating factor active on mouse bone marrow cells was also able to stimulate the growth of swine bone marrow cells in a liquid culture system. During the first 4 days of culture mononuclear phagocyte and granulocyte colonies developed. Prolonged cultured cells were classified belonging to the macrophage lineage by morphological and cytochemical criteria. These cells fulfill also functional characteristics for macrophages, like expression of Fc receptors, immune phagocytosis and production of prostaglandins. These bone marrow-derived macrophages could also be activated with LPS and lymphocyte-derived mediators. 相似文献
The latent periods of Visna virus and of progressive pneumonia virus were demonstrated by one-cycle growth studies to end 14–16 hr after infection of sheep choroid plexus cell cultures. Maedi virus was demonstrated to have a 14–18-hr latent period. 相似文献
The inhalation of grain dust by grain workers is responsible for a large number of pulmonary pathophysiologies. These problems may be acute or chronic and may be mediated by the chronic activation of the immune system. Constant inflammatory states in the lung may eventually lead to tissue damage and respiratory deficit. This study was designed to measure the changes in the relative number of inflammatory cells in peripheral blood, bronchoalveolar spaces, and lung interstitium that occur in response to intratracheally instilled airborne spring wheat dust in rats. It was found that 6h after instillation with dust, neutrophils were present in greater numbers in the blood and bronchoalveolar spaces than in lung interstitium. After 24h, there appeared to be a larger number of neutrophils in the lung interstitium in dust-instilled animals than in saline-instilled controls. These results indicate that intratracheal instillation of grain dust initiates an acute inflammatory reaction, and that there is an initial influx of neutrophils into the air spaces of the lung followed by transit of these cells into the lung interstitium. 相似文献
A sheep-pox virus strain has been adapted and multiplied in primary lamb kidney cell cultures. The main characteristics of the strain have been verified in vitro after clones were isolated, and the results confirmed its identity. The safety and the potency of the strain have been investigated in sheep.
The inoculation of the strain to sheep was followed by a post-vaccinal reaction materialised by a nodule at the site of inoculation and an increase of temperature by about 1°C. No reactions adversely affecting pregnancy have been noted. Immunisation was demonstrated by an increase in the level of neutralising serous antibodies and protection against the pathogenic virus. The immunity tended to decrease during the second year after primovaccination and a yearly booster vaccination appeared to be necessary. Primovaccination of lambs over 2 months of age produced a better immunity, especially when the lambs were born from vaccinated ewes.
This strain forms the active principle of a freeze-dried vaccine containing no adjuvant of the immunity. 相似文献
The human urinary tract is able to combat with the microbial invasion under normal circumstances. To cause urinary tract infection the organism has to evade the host defense mechanisms by possessing distinct properties which contribute to the virulence of the organism hence called virulence determinants Ninety percent of uncomplicated urinary tract infections are caused by Escherichia coli, hence the knowledge of the virulence determinants of this organism can be extrapolated to other uropathogenic organism as well. Virulence determinants of uropathogenic E. coli include adhesins, siderophore production, polysaccharide coating, hemolysin production, outer membrane proteins etc. The intestinal E. coli, which are the reservoir of E. coli for causing UTI, lack these virulence determinants. On the other hand these virulence determinants enable the organism to colonize and invade the urinary tract. In addition these are important in acquiring the nutrients in other wise nutrient deficient environment. Further, they also help the organisms in triggering an inflammatory response and hence bringing about pathological changes which leads to symptomatic UTI. Severity of symptomatic infections and tissue damage during the infective process depends upon the magnitude of the inflammatory response triggered by the uropathogen which in turn is dependent upon the amount of extrcellular release of reactive oxygen species by the phagocytic cells; hence role of antioxidants as an adjunct to antibiotics in the treatment of infective process needs to be evaluated further. 相似文献
Aerosol administrations of RIT 4030 and other available vaccine strains have been carried out in SPF and in conventional chickens. The results indicate that the RIT 4030 and Ulster 2C strains are significantly less reactogenic than the LaSota and the Hitchner B1 strains.The RIT 4030 strain produces an immune response even when administered to chickens with maternal antibodies and induces a better protection to challenge than the Ulster 2C strain.The replication of the RIT 4030 strain in the respiratory tract will be discussed with respect to its attenuation and transmissibility. 相似文献
Standardised procedure for obtaining reproducible haemagglutination-inhibition results for FPV antibody which correlate with serum-neutralization titres was described. Optimal conditions were found to be Alsevers anticoagulant, PBS/0.05% BSA (pH 6.8) as buffer, especially washed round bottom microplates, determination of maximally sensitive porcine erythrocytes, use of reproducible erythrocyte concentrations, inactivation of serum samples at 56 degrees C for 30 min and serum treatment with koalin pH 9.0. The concentration of erythrocyte used for estimation of haemagglutination units in H1 test should not differ from that used as indicator in the test. Predilution of serum beyond 1:4 associated with false results. Reproducible method for removing natural agglutinins in serum by adsorption with erythrocytes was described. 相似文献
From each of two lentogenic Newcastle disease virus (NDV) strains of the type LaSota and Hitchner B1 a virulent subpopulation could be obtained. The two subpopulations were—in comparison to the two parent viruses—more resistant to the lipid solvent chloroform and more stable against thermal degradation. Also, the glycoproteins haemagglutinin and F (fusion) were more stable against thermal inactivation. Electron microscopic observations revealed in terms of size and morphology all of the characteristics of NDV. Both subpopulations possessed, however, the same elution kinetics as their respective parent strains. The intracerebral and intravenous pathogenicity indices as well as the mean death times of the two subpopulations allow to classify these viruses as virulent Newcastle disease viruses. 相似文献