首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 15 毫秒
1.
Immunoblotting of Cowdria ruminantium proteins with sheep or bovine antiserum identified 2 antigenically conserved proteins, one being an immunodominant 31 kDa and the other a minor 27 kDa protein. These proteins are present in the electrophoretic profiles of the Welgevonden, Ball 3 and Kwanyanga stocks and are recognized by sheep antiserum to the Welgevonden, Ball 3, Kwanyanga, Mali, Comoro, Breed, Germishuys, Kümm and Mara stocks and by bovine antiserum to the Welgevonden stock of C. ruminantium. The stocks did not reveal identical or unique antigenic properties which could explain differences in pathogenicity and cross-immunity observed amongst the various stocks of C. ruminantium.  相似文献   

2.
Lyophilized tissues of mice and blood of sheep, infected with either the Kümm, the Welgevonden or the Ball 3 stock of Cowdria ruminantium, remain infective to mice and sheep after storage at 4 degree C for 90 days. Freeze-dried tissues stored at -18 degrees C and -28 degrees C are still infective after 6 months and 2 years, respectively.  相似文献   

3.
Neither sheep immune to the Ball 3, the Kwanyanga or the Mara stocks of Cowdria ruminantium nor those immunized with combinations of these 3 stocks were protected against challenge with the Mali stock. Against challenge with the Welgevonden stock, however, immunization with each of the 3 combinations and with single stocks effected a protective immunity.  相似文献   

4.
The present state of Cowdria ruminantium cultivation in cell lines   总被引：3，自引：0，他引：3  
Attempts were made to grow 4 isolates of Cowdria ruminantium in cell lines. Three of these isolates, viz. Ball 3, Welgevonden and Kwanyanga, could be cultivated in a calf endothelial cell line, but experiments with the Kümm isolate have so far failed. The successful in vitro cultivation of 2 isolates (Welgevonden and Kwanyanga), which are also pathogenic for mice, has great potential for future studies and these aspects are discussed in this review.  相似文献   

5.
A cell line of bovine endothelial cells (E5), infected with 3 different stocks of Cowdria ruminantium, was used as antigen in an indirect fluorescent antibody test for the serodiagnosis of heartwater. These antigens were compared to peritoneal macrophages from mice infected with the Kümm stock and to caprine neutrophils in primary cultures from goats infected with 4 different stocks of Cowdria. The use of endothelial cell cultures proved to be superior in all respects. The antigens can be produced in large quantities at a low cost, contrary to the other types. The reaction is easily and quickly read, compared to the laborious reading of neutrophil or macrophage antigens which often contain few and small colonies of Cowdria. Moreover, not all stocks are suitable for the preparation of neutrophil antigens, while macrophage antigen can only be obtained with the Kümm stock. Endothelial cell antigens also distinguish serotypes in C. ruminantium, but these differences seem to be less pronounced than those found with neutrophil antigens. Finally, the specificity of endothelial cell antigens appears to be better than that of Kümm antigen and comparable to that of neutrophil antigens. The use of Kümm antigen may have been responsible to a large extent for past unexplained positive serological results on certain Caribbean islands where it has not been possible to isolate Cowdria and where no clinical evidence of the disease has been found.  相似文献   

6.
The inability of athymic nude mice to make a drug-aided recovery from infection with either the Kümm or the Welgevonden stocks of Cowdria ruminantium and their inability to mount an immune response, suggest that immunity in heartwater is cell-mediated. The adoptive transfer of immunity with the spleen cells of mice immune to the Welgevonden stock is supportive evidence. Immune spleen cells depleted of Lyt-2+ T cells are unable to confer resistance to challenge to recipient mice, whereas the depletion of L3T4+ T cells had no effect on the protection conferred by immune spleen cells. This is conclusive evidence that immunity in heartwater is largely cell-mediated. Immune serum, C. ruminantium and complement incubated in the presence of mouse peritoneal macrophages, inhibits the infectivity of the heartwater agent, but not in the absence of macrophages. The decreased resistance to challenge of immune mice treated with gloxazone adds further support to the concept that in heartwater persistence of C. ruminantium in the host is associated with immunity.  相似文献   

7.
Nineteen per cent and 32% of serologically positive sheep and goats in heartwater endemic areas of the Republic of South Africa were susceptible to challenge with, respectively, the Ball 3 and Welgevonden stocks of Cowdria ruminantium. There was good correlation between the results of the indirect fluorescent antibody test and immunity, since without exception all the seronegative animals reacted when they were challenged. The fact that only 74% of the seropositive sheep and goats were immune to challenge can probably be ascribed to the poor cross-protection between stocks of C. ruminantium and not to false positive serological reactions.  相似文献   

8.
Four stocks of Ehrlichia ruminantium (Welgevonden, Ball3, Nonile and Blaauwkrans), the causative agent of heartwater in domestic ruminants, were isolated into Ixodes scapularis (IDE8) tick cells using the leukocyte fraction of the blood of infected sheep. Organisms of two of the E. ruminantium stocks (Welgevonden and Blaauwkrans) propagated in IDE8 cells were also successfully used to infect bovine endothelial cells. All stocks were successfully propagated in IDE8 cells using Dulbecco's modified Eagle's medium nutrient mixture Ham F-12 containing 10% foetal bovine serum (FBS). The technique should be included in any attempt to isolate uncharacterized E. ruminantium stocks.  相似文献   

9.
Heartwater serology: some problems with the interpretation of results   总被引：6，自引：0，他引：6  
Antibodies in the sera of domestic ruminants that have been infected with Ehrlichia bovis and other ehrlichial agents cross-react with the Kümm strain of Cowdria ruminantium used in the indirect fluorescent antibody test as antigen. These cross-reactions are also shown by the Elisa test in which the Ball 3 strain of the heartwater agent is used as antigen.  相似文献   

10.
Antigenic diversity in five stocks of the tick-borne rickettsia Cowdria ruminantium, the causal agent of heartwater disease of ruminants, was studied by cross-immunity trials in goats and sheep. Complete absence of cross-protection was found only between the Kümm and Kwanyanga stocks, and in all other combinations there were various degrees of cross-immunity. Immunological strain differences were more pronounced in goats than in sheep.  相似文献   

11.
Antigenic diversity of Theileria annulata macroschizonts   总被引：2，自引：0，他引：2  
A series of monoclonal antibodies has been produced which reacts with the intracellular macroschizont of Theileria annulata, and this series has been used to examine the level of antigenic diversity between and within stocks of the parasite in addition to species specificity within the genus. The majority of the monoclonal antibodies (six of eight) reacted with all stocks tested and four were species-specific. Two monoclonal antibodies detected variation between stocks and within stocks. The variation within a stock was manifest as only a proportion of the macroschizonts reacting with the monoclonal antibody. This was demonstrated as being due to the strain containing more than one antigenic type of parasite by cloning the infected lymphocyte cell line and showing that the resulting cloned cell lines were antigenically homogeneous. The variation between stocks allowed them to be divided into three groups on the basis of antigenic profile.  相似文献   

12.
An effective culture system for Ehrlichia (Cowdria) ruminantium comb. nov. was first established in 1985 and many stocks were subsequently isolated and propagated in vitro. A notable exception, however, was the Kümm isolate that resisted all attempts at in vitro culture until the successful experiment described here. In one experiment white blood cells were harvested from heparinized blood derived from a sheep infected with the Kümm isolate. The cells were added to DH 82 cells and incubated at 37 degrees C. The high metabolic activity of the DH 82 cells necessitated that cell growth be retarded by the addition of cycloheximide. Colonies were first detected 19 days after culture initiation and, once the cultures were established, they could be passaged every 3 days. Bovine and sheep endothelial cells were readily infected with culture supernatant obtained from the infected DH 82 cells. In a further experiment another sheep was infected, using a higher dose of the same batch of Kümm stabilate, and we attempted to infect several different cell lines: these were DH 82 cells, bovine aorta (BA 886) cells, sheep brain endothelial (SBE 189) cells and sheep fibroblastoid cells (E2). Ten days after culture initiation only the E2 cells had become positive for E. ruminantium. Culture supernatant from the first cultured isolate (Kümm-1) was less virulent for mice than that of the second cultured isolate (Kümm-2) which killed all mice. Upon molecular characterization with E. ruminantium 16S probes we found that Kümm-1 hybridized with a Senegal 16S genotype probe, whereas Kümm-2 hybridized only with an Omatjenne 16S genotype probe. The original stabilate used to infect the sheep hybridized with both probes. These results clearly indicate that two different stocks had been isolated in culture.  相似文献   

13.
Antigenic differences between stocks of Cowdria ruminantium   总被引：8，自引：0，他引：8  
Stocks of Cowdria ruminantium from Senegal, Zambia and South Africa were compared in cross immunity tests in goats. The Senegal stock caused fatal heartwater in three of 10 goats immune to the South African reference stock Ball 3, and five others showed significant febrile reactions and recovered spontaneously. Four goats immune to the Senegal stock did not show any reaction on challenge with Ball 3. The stock from Zambia was fully cross-protective with Ball 3 in experiments with three goats, but these three goats, immune to the Zambia stock and to Ball 3, showed severe febrile responses upon further challenge with the Senegal stock. The Senegal stock was highly virulent for Dutch goats and there were exceptionally large numbers of rickettsiae in brain capillaries after death. This stock has been passaged eight times in mice, without causing disease; the presence of the organism in the mice was shown by subinoculating goats. The Senegalese stock of C ruminantium is the first stock outside South Africa against which the reference Ball 3 stock does not fully immunise.  相似文献   

14.
An attempt to establish an inbred line of mice resistant to Cowdria ruminantium failed. First generation couples were constituted from those mice out of 100 males and 100 females that had survived infection with the Kümm stock of C. ruminantium and that were serologically negative to the indirect fluorescent antibody test. An attempt to establish 10 separate inbred lines by constituting next generation brother and sister matings from predominantly seronegative survivor mice from the preceding generation, was unsuccessful because too few mice survived the challenge. The percentage seronegative survivors increased to 94% over the first 6 generations, but then declined sharply during the next.  相似文献   

15.
Two antigenically different stocks of Theileria parva parva (Kilifi and Marikebuni), previously characterized as belonging to groups A and C respectively on monoclonal antibody (MAb) profiles, were selected for immunization of different breeds of cattle against East Coast fever (ECF) by the infection and treatment method. A total of 52 immunized cattle and 33 susceptible controls of different group sizes were exposed to field challenge by ticks for periods of 42-90 days at three field sites where ECF is endemic on the Kenyan coast. All immunized cattle survived ECF challenge, but 87% of the controls died of the disease. The cattle exposed at one site had been immunized 1 year earlier and maintained tick-free in the intervening period. The level of immunity in these cattle was similar to that of cattle which had been immunized 1 or 2 months prior to exposure. Thus, immunity had not waned over the 1-year period. A study at another site showed that acaricidal treatment of immunized cattle could be safely extended from twice a week to once every three weeks, whereas in susceptible cattle even twice weekly spraying did not control ECF. The isolates made from infected controls during the trials indicated the presence of three T. p. parva stocks as defined by MAb profiles. Of the two stocks used for immunization, T. p. parva Marikebuni induced broader protection. In view of the apparent limited antigenic diversity of T. p. parva strains within the Coast Province it is suggested that the Marikebuni stock might represent a key stock for vaccination in this area.  相似文献   

16.
Chemically defined media, termed SFMC-23 and SFMC-36, were devised for the in vitro culture of Cowdria ruminantium, the causative agent of heartwater in domestic ruminants. Both media were based on Dulbecco's modified Eagle's medium nutrient mixture Ham F-12 (DME/F-12) containing various supplements. Medium SFMC-23 and SFMC-36 supported the long-term growth of the Welgevonden stock of C. ruminantium for a total of 55 and 28 passages, respectively, with regular passage intervals of 3 days. Using SFMC-23, split ratios varied from 5-10, depending on which host cell line was used. Other stocks of C. ruminantium (Sankat, Blaauwkrantz, Senegal) were successfully propagated for a test period of ten passages.  相似文献   

17.
Lung lesions in sheep and goats infected with the Ball3 strain of Cowdria ruminantium corresponded with those reported in mice infected with the Welgevonden strain of Cowdria ruminantium. Ultrastructural changes in the alveolar endothelial and epithelial cells are described and the pathogenesis of the lung oedema is briefly discussed.  相似文献   

18.
The Welgevonden stock of Ehrlichia ruminantium, aetiological agent of heartwater, was propagated in baby hamster kidney (BHK) cells, Chinese hamster ovary (CHO-K1) cells and Madin Darby bovine kidney (MDBK) cells. The cultures required supplementation of the medium with cycloheximide for reliable growth of E. ruminantium. Growth of the Welgevonden stock in BHK and CHO-K1 cells could lead to the development of suspension cultures suitable for the mass production of E. ruminantium for an inactivated elementary body vaccine.  相似文献   

19.
Theileria parva parva Marikebuni stock, previously shown to give good protection to immunised cattle in Kilifi District, Coast Province of Kenya, was chosen for large scale immunisation in the district. A large sporozoite stabilate was prepared and evaluated for efficacy and safety in the 'infection and treatment' method, using a long or short acting formulation of oxytetracycline. Susceptible cattle were infected with selected doses of stabilate (10(0), 10(-1), 10(-1.7) and left either as untreated controls, or treated with one of the two oxytetracycline formulations. It was concluded that stabilate dilution at 10(-0.7) or 10(-1) in combination with either formulation of oxytetracycline would effect satisfactory immunisation. The short acting oxytetracycline treatment was judged to be the most efficacious in protecting cattle against homologous challenge. On heterologous challenge it was found that T p parva Marikebuni immune cattle were protected against seven T p parva stocks from Kilifi District and also against four stocks of T p parva from other areas of Kenya. In addition, the Marikebuni stock provided partial protection against challenge by T p lawrencei stocks. Furthermore, cattle immune to T p parva and T p lawrencei were protected against lethal challenge of T p parva Marikebuni stock. Thus, it appears that large scale immunisation of cattle against theileriosis in Kilifi District could be undertaken using the Marikebuni stock. With continued assessment, this stock could provide a master theilerial stock for immunisation against cattle theileriosis in areas free of buffaloes elsewhere in Kenya.  相似文献   

20.
Amblyomma hebraeum ticks, collected in the field and individually homogenized, were injected into mice. Thirteen out of 240 ticks were shown to be infected with the heartwater agent. Antibodies against Cowdria ruminantium were detected in the sera of the mice by means of the indirect fluorescent antibody test. Giemsa-stained smears, prepared from the haemocytes of the ticks, revealed morphologically different forms of the heartwater agent. A strain of C. ruminantium, designated the Welgevonden strain, was isolated in mice from one of the infected ticks and passaged in mice for 8 generations. When inoculated intravenously, it was highly infective to mice, sheep and cattle. The murinotropism of the Welgevonden strain is compared with that of other strains previously described.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号