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 644 毫秒
1.
Mononuclear leukocytes (MNC) were separated from heparinized and EDTA-treated whole bovine blood by centrifugation after mixing with a commercial colloidal silica preparation (Sepracell-MN (S-MN]. Cell yields and lymphocyte blast transformation (LBT) to pokeweed mitogen (PWM), phytohaemagglutinin (PHA), concanavalin A (Con A), and Brucella abortus antigens were tested against MNC obtained from heparinized whole blood using Ficoll-Hypaque (FH). Separation with S-MN was more rapid and less labor intensive than separation with FH. There was a higher average total yield of MNC but a lower percentage of monocytes in the FH- than in the S-MN-separated MNC. In mitogen-induced LBT assays, MNC responded comparably to each mitogen regardless of the separation technique or anticoagulant used, and a cell concentration effect was demonstrated. In general, FH-separated MNC responded greater to PWM than did S-MN/EDTA separated MNC, but S-MN/heparin separated MNC had the greatest LBT responses to PWM. Overall, S-MN/EDTA separated MNC had the greatest responses to PHA, and responses to Con A were variable among experiments with respect to the separation technique. In antigen-induced LBT assays, two B. abortus antigens were used: a heat-killed strain S1119 (HKA) and a gamma-irradiated strain 19 (gamma BA). The LBT responses of three steers vaccinated with live B. abortus strain 19 were compared with three nonvaccinated steers in three separate experiments. Using HKA, FH separation resulted in an overall greater LBT response for vaccinates than nonvaccinates and a greater differential between responses of vaccinates and nonvaccinates than did S-MN derived MNC regardless of the anticoagulant used. Using gamma BA, FH produced the most responsive MNC in one experiment and S-MN/heparin produced the most responsive MNC in the other. At the highest cell concentration tested, FH-separated MNC had the greatest LBT responses for vaccinated calves, but differences between S-MN- and FH-separated MNC responses were not significantly different (P greater than 0.05). In conclusion, S-MN is a rapid and simple technique for separation of MNC from bovine blood. The technique produces an adequate cell population for mitogen-induced LBT studies; however, FH-separated MNC were generally more responsive in the B. abortus-induced LBT assay.  相似文献   

2.
Five different adjuvants were examined for potentiation of humoral and cell-mediated immune (CMI) responses in cattle to a Brucella abortus soluble antigen (BASA). Two separate experiments were performed involving a total of 64 steers, divided among six groups (Experiment 1) and 9 groups (Experiment 2). The adjuvants used were: muramyl dipeptide, Freund's incomplete adjuvant, dimethyl-dioctadecyl ammonium bromide (DDA), Bordetella pertussis and Propionibacterium acnes. In each experiment, three groups received BASA (2 mg protein) subcutaneously with adjuvant, one group received a reduced dose of B. abortus Strain 19 (S19), one group served as unvaccinated controls, and another group received BASA alone. Primary responses were studied following a single immunization in comparison to the single inoculation with S19. For each experiment serum antibody responses and CMI responses were sequentially determined over a period of 56 days. Antibody responses to B. abortus were measured using the brucellosis card, rivanol precipitation-plate agglutination, complement fixation, and fluorometric immunoassay tests, and as well as with an enzyme-linked immunosorbent assay. The CMI response was measured using antigen-specific lymphoproliferation (LP) and skin testing for delayed-type hypersensitivity (DTH) to BASA (Experiment 2). Specific aspects of induced CMI responses investigated were macrophage activation (IL-1 production), helper T cell activation (IL-2 production), and release of soluble suppressor factor(s). In general, mean antibody responses were significantly higher (P less than 0.05) in immunized steers than in control steers and those receiving BASA alone. The LP responses to heat-killed B. abortus were generally higher in immunized groups than in the controls. The LP and DTH responses were greatest in the groups receiving S19 and BASA + DDA. Increased induction of IL-1 was largest in the group receiving BASA + DDA whereas IL-2 release was greatest in S19 vaccinated steers. Suppressor T cell responses were most obvious in the groups receiving S19, BASA + B. pertussis, and P. acnes. These studies demonstrated that DDA potentiates CMI responses to a soluble B. abortus antigen and may be useful as an adjuvant for future vaccines, particularly subunit vaccines.  相似文献   

3.
The in vivo and in vitro effects of Trichinella spiralis excretory-secretory (ES) antigens on porcine peripheral blood lymphocyte (PBL) responses induced with mitogens (phytohemagglutinin, PHA; concanavalin A, Con A; pokeweed mitogen, PWM) or unrelated antigen (Protein A) were studied to determine whether ES antigens depress lymphocyte responses in experimental swine trichinosis, and/or if this response was manifested after lymphocytes from infected pigs had been pretreated with ES antigens. Additionally, the range of inhibition of lymphocyte responses was tested in parasite-free pigs using different doses of ES antigens and compared with the responsiveness of control cultures from the same animals. The responses of lymphocytes from pigs inoculated with 4 x 10(3) muscle larvae (ML) were strongly depressed (P < 0.05) at post-inoculation days (PID) 7 (after stimulation with PHA), 14, 35 (Con A or PWM), and 49 (PWM). At PID 56 and 63 the lymphocytes from T. spiralis-infected pigs responded better (P < 0.05) to all three mitogens than those from non-infected controls. After 7 weeks post-inoculation, PBL which were pretreated with 10 or 250 micrograms ml-1 of ES antigens showed significantly weaker (P < 0.05, P < 0.001) responses to PWM or PHA, respectively, than those from non-infected animals. The responsiveness of lymphocytes from both groups of pigs to Protein A was not affected by the pretreatment with ES antigens in vitro. The responses of lymphocytes from the parasite-free pigs induced by PHA, PWM or Protein A were strongly depressed (P < 0.01) after in vitro pretreatment regardless of the dose of ES antigens (5, 10, 15, or 20 micrograms ml-1) applied.  相似文献   

4.
Cell-mediated immune responses in cattle naturally infected with strains of Brucella abortus and in cattle vaccinated with B abortus strain 19 during calfhood were studied by an in vitro lymphocyte-stimulation procedure. Lymphocytes were prepared from peripheral bovine blood by the Ficoll-diatrizoate technique, suspended in RPMI-1640 medium (1.5 X 10(6) lymphocytes/ml), cultured with B abortus-soluble antigen or phytohemagglutinin, and incubated for 6 days. Sixteen hours prior to termination of incubation, cultures were labeled with 1 muCi of [3H]thymidine (3HdT) and, after harvesting, assayed for 3HdT incorporation into DNA by liquid scintillation spectrometry. Lymphocytes from cattle with bacteriologically confirmed isolation of B abortus underwent a significantly higher lymphocyte stimulation with B abortus-soluble antigen than did cattle vaccinated with B abortus strain 19 during calfhood (P less than 0.005). Standard seroagglutination tests were conducted simultaneously with lymphocyte-stimulation tests, but there was no apparent correlation between levels of humoral antibodies and the cell-mediated immune responses as measured by in vitro specific lymphocyte stimulation.  相似文献   

5.
Immune responses and lymphoreticular morphology were studied in 3 groups of yearling Hereford steers fed hypoalimentative, maintenance and hyperalimentative diets for 142 days. Significant decreases in plasma protein levels and circulating lymphocyte levels occurred in low energy intake steers. Percent circulating lymphocytes bearing surface immunoglobulins and serum levels of IgG and IgM did not vary significantly within or between groups. Antibody responses to Brucella abortus bacterin inoculated on day 63 were similar in all 3 groups. Antibody responses to chicken erythrocytes inoculated on day 88 were significantly lower in hypoalimentated steers. Differences between groups in lymphocyte blastogenic responses to phytohemagglutinin (PHA), concanavalin A (Con A) and pokeweed mitogen (PWM) were not significant. Hyperalimentated steers had significantly depressed PWM responses compared to a baseline value established for that group. In addition, hypoalimentated steers tended to have elevated responses to PHA, although differences were not significant. There were no significant differences between groups in dermal hypersensitivity responses to tuberculin following sensitization with viable Bacillus Calmette-Guerin (BCG). The thymuses of hypoalimentated steers were markedly atrophied but lymph nodes and splenic white pulp were normal. Thymus, lymph nodes and spleen were normal in hyperalimentated steers.  相似文献   

6.
Culture extracts of in vitro grown Brucella abortus were demonstrated to cleave a part of the Fc portion of bovine immunoglobulin G1 in whey but not in serum or as a purified protein from serum. Supernates from Strains 19 and 2308 of B. abortus were both capable of this hydrolysis whereas living cells were not. The cleavage process was independent of antibody activity to B. abortus, appeared to require factor(s) found only in some whey samples and was ineffective with the other bovine immunoglobulins.  相似文献   

7.
Incubation of Brucella abortus (field strain) infected and strain 19 vaccinated bovine peripheral blood lymphocytes with B. abortus antigen and levamisole caused a consistently significant increase in [3H] thymidine uptake when compared to cultures without levamisole. Levamisole did not potentiate B. abortus-induced blastogenic response of lymphocytes from non-exposed cattle. A dose response study showed that 10 micrograms/culture induced maximum potentiation of B. abortus-induced lymphocyte stimulation. Using the 10 micrograms/well concentration of levamisole, further studies were conducted to determine the net potentiation of the blastogenic responses in lymphocytes from B. abortus (field strain) infected cattle. B. abortus strain 19 vaccinated but nonresponsive and non-exposed cattle. Levamisole significantly potentiated the B. abortus-induced lymphocyte blastogenesis in lymphocytes from unresponsive cattle.  相似文献   

8.
Augmentation of immunization of cattle Brucella abortus S19 or a B. abortus soluble protein extract (SPEBA) vaccine through administration of recombinant bovine IL 2 (rBoIL 2) was evaluated. Seventy-five heifers were divided among 6 groups that were treated with the following: Group 1, no treatment; Group 2, rBoIL 2 (1microg/kg) on day 0; Group 3, SPEBA (2 mg) on day 0 and week 9; Group 4, SPEBA + rBoIL 2 on day 0, SPEBA on week 9; Group 5, S19 (10(7) CFU) on day 0 and week 9; Group 6, S19 + rBoIL 2 on day 0, S19 only on week 9. Approximately, 6 months after vaccination, cattle were bred by natural service, and at mid-gestation pregnant cattle were challenged intraconjunctivally with 9.1 x 10(5) CFU of virulent B. abortus S2308. Pre- and post-challenge antibody responses were measured by an enzyme-linked immunosorbent assay, a particle concentration fluorescence assay, and the card test. Lymphoproliferation (LP) responses to gamma-irradiated B. abortus and SPEBA antigens were measured in peripheral blood mononuclear cells. After vaccination, antibody responses to B. abortus elevated rapidly in SPEBA- and S19-vaccinates with and without rBoIL 2, however, these responses were significantly (P < 0.05) higher in vaccinates which also received rBoIL 2. Antibody levels for all vaccinated groups had returned to those of negative control groups by the challenge date with the exception of the SPEBA/rBoIL 2 group. In general, LP responses were higher in vaccinated or rBoIL 2-treated cattle than for unvaccinated controls. Challenge of 48 pregnant heifers resulted in abortions in 4/9 of Group 1, 0/9 of Group 2, 4/8 of Group 3, 2/9 of Group 4, 1/7 of Group 5, and 0/6 of Group 6 cattle. Treatment with rBoIL 2 alone (Group 2) provided significant (P < 0.05) protection from infection, abortions and induction of sero-positive status compared to untreated (Group 1) cattle. Co-administration of rBoIL 2 with S19 resulted in significant (P < 0.05) augmentation in onset, duration and magnitude of LP responses to B. abortus antigens following challenge. Characterization of the cytokine response of bovine monocyte-derived macrophages by real-time polymerase chain reaction indicated that in vitro stimulation of these cells with rBoIL 2 resulted in a profound up-regulation of genes encoding tumor necrosis factor-alpha, IL 12p40, and interferon-gamma reflecting activation of the cells. Overall, rBoIL 2-treatment was associated with fewer infections, sero-conversions and a significant (P = 0.02) level of protection against abortion as compared to vaccination alone or no treatment.  相似文献   

9.
Fifty-four cattle were sensitised to Brucella antigens either by vaccination with Brucella abortus strain 19 (S19) or B. abortus 45/20 (S45/20) and 24 of these were challenged 12 weeks after mating with virulent B. abortus strain 544 (S544). A further 12 cattle which were not vaccinated were exposed to S544. After 40 weeks, all these cattle (66), together with 5 cattle which were not sensitised by vaccination or challenge were subsequently inoculated with one dose of S45/20 and the anamnestic response was measured by the complement fixation test. Ten to 15 weeks later the cattle were slaughtered and tissues cultured. Of the 52 (2 died) vaccinated cattle, 35 gave a positive anamnestic response and 20 of these were not challenged. Of the 17 unvaccinated cattle, one gave a positive response and this animal had been exposed to S544 prior to the inoculation with S45/20. The results indicated that the method had a level of sensitivity of 75% and specificity of 100% in serologically negative cattle that had been exposed previously to Brucella antigens. An evaluation of the method for detecting serologically negative, but infected cattle was not possible as the number of cattle suitable for examination in this study was too low.  相似文献   

10.
An O-polysaccharide (O-chain) and a hot-water extracted polysaccharide (PS), both obtained from Brucella abortus 1119-3, and a B. melitensis 16M native hapten (NH) were evaluated by indirect enzyme linked immunosorbent assay (ELISA) on three groups of cattle sera. The sera tested were: (a) 75 sera from cows naturally infected with B. abortus; (b) 130 sera from non-infected and non-vaccinated cattle; and (c) 61 sera from non-infected heifers recently vaccinated with B. abortus Strain 19 (S19). Sensitivity (Se), specificity (Sp) and the capability to discriminate vaccinated cattle (ADV) were determined. Using PS antigen, Se was 100% and the Sp was 97.7%, while the highest Sp was obtained by using the O-chain (99.2% ). For the NH antigen, Se was 94.7% and the Sp was 90.0%. The ADV of the three antigens was approximately 85%. Statistical analysis showed significant differences between O-chain/PS and O-chain/NH antigens. The agreement among antigens determined by kappa coefficient was 0.899 for O-chain/PS, 0.845 for O-chain/NH and 0.795 for PS/NH.  相似文献   

11.
The outer membrane-peptidoglycan complex (OM-PG) from rough strains of Brucella abortus was tested for its ability to induce lymphocyte responsiveness in cattle. Six groups of heifers were immunized with varying doses and administration schedules of rough OM-PG and assayed for responsiveness of their lymphocytes in proliferation assays in vitro. All OM-PG preparations were emulsified in a commercial adjuvant for administration. Two other groups of heifers were immunized with strain 19 vaccine or adjuvant alone. Three groups of heifers received two inoculations of OM-PG antigens from a naturally-occurring rough strain at a 57-day interval. The doses of OM-PG given in these three groups were 400 micrograms, 1200 micrograms, and 4000 micrograms at each inoculation. The frequency of cows that responded in lymphocyte proliferation assays increased with the dose of OM-PG given. Two groups received single inoculations of OM-PG, either 2400 micrograms or 8000 micrograms. Although there were responsive cows in these immunization groups, their frequency was lower than in the groups receiving the same total dose in two inoculations. A sixth group of cows was inoculated with OM-PG from a rough transposon mutant of B. abortus, and the frequency of responsive cows in this immunization group was comparable to that of responsive cows immunized with the same dose of OM-PG from the spontaneous rough mutant. In comparisons of cows inoculated with strain 19 to those inoculated with OM-PG preparations, differences were observed in the relative responsiveness of their lymphocytes to whole cells and OM-PG in the in vitro lymphocyte proliferation assays. These differences suggested that lymphocytes stimulated by strain 19 vaccination have different specificities than those stimulated by immunization with OM-PG of rough mutant strains of B. abortus.  相似文献   

12.
A Brucella abortus-soluble antigen was investigated, using in vitro assay of lymphocyte immunostimulation, to determine which concentration of this antigen and which period of incubation of the lymphocyte cultures would induce maximum specific lymphocyte immunostimulation as an additional method for further study of B abortus infection in cattle. Soluble antigen was prepared from autoclaved cells of B abortus strain 1119-3. Peripheral blood lymphocytes were obtained from cattle infected with B abortus and from healthy control cattle not infected with B abortus. The lymphocytes were prepared by the Ficoll-Hypaque density gradient technique, suspended in RPMI 1640 medium (1.5 X 10(6)/ml), cultured with several dilutions of soluble antigen, and incubated. Prior to termination of incubation, cultures were labeled with 1 muCi of [3H]thymidine and, after harvesting, assayed for [3H]thymidine incorporation in DNA by a liquid scintillation spectrometer. Maximum specific immunostimulation of lymphocytes from B abortus-infected cattle was induced in this assay system with 6 days' incubation and 22 microgram of protein/ml/1.5 X 10(6) lymphocytes, using protein content to express concentration of soluble antigen in this system.  相似文献   

13.
Two experiments were done on 57 steers. These cattle were allotted to 8 groups (4 groups/experiment) and vaccinated with 1 to 3 X 10(9) colony-forming units of Brucella abortus strain 19. Cattle in 3 of the 4 groups/experiment were given 6 mg of levamisole/kg, subcutaneously, either at the time of vaccination (day 0), 7 days later, or at both times. Serum antibody titers to B abortus were measured sequentially for 28 days in experiment 1 and for 56 days in experiment 2, using the card test, Rivanol test, complement-fixation test, fluorometric immunoassay, and an enzyme-linked immunosorbent assay. In general, the highest mean antibody titers, as determined by all serologic tests, occurred in steers treated with levamisole at 7 days after vaccination or in those treated at the time of vaccination and 7 days later. By the card test on day 56, there was a significantly (P less than 0.05) greater number of seropositive cattle among those given levamisole 7 days after seropositive cattle among those given strain 19 alone. Simultaneous administration of strain 19 and levamisole did not alter antibody responses to B abortus.  相似文献   

14.
The present study was an investigation into the role of T lymphocytes in the killing of antigen-sensitized macrophages (MΦ) in bovine brucellosis. Following confirmation of bovine T lymphocyte cell lines derived from Brucella abortus Strain 19 vaccinated steers as antigen-specific in proliferation studies using various antigens, we adapted an apoptosis assay for evaluation of cytotoxicity by these bovine T cells against autologous monocyte-derived macrophages (MDMΦ) as target cells. Various B. abortus antigen preparations were tested including whole γ-irradiated B. abortus bacteria (γBA), a soluble cytosolic protein fraction and a membrane-associated protein fraction. Both polyclonal and cloned T lymphocyte cell lines exhibited cytotoxicity against MDMΦ targets in an antigen-specific fashion. Polyclonal and cloned T lymphocyte cell lines demonstrated cytotoxic responses to varying degrees against B. abortus antigens regardless of whether the antigen used was whole nonviable bacteria, a soluble protein extract or a membrane-associated fraction of extracted bacteria. To further develop correlation of these responses to an in vivo host defense mechanism, cytotoxicity was evaluated using target cells that had been infected with live B. abortus S19 or B. abortus Strain 2308. Cytotoxic responses were also demonstrated consistently against infected targets with either strain of B. abortus although in most cases, cytotoxicity was higher against target cells sensitized with γBA compared to those infected with live bacteria. Cloned T lymphocyte cell lines were all CD4+, CD8− cells indicating that the observed cytotoxic responses were most likely due to an inflammatory Th1 response and may represent an important host defense mechanism induced by vaccination with live attenuated strains of B. abortus in cattle.  相似文献   

15.
The adjuvant effects of dimethyl dioctadecyl ammonium bromide (DDA) alone or in combination with trehalose dimycolate (TDM) or muramyl dipeptide (MDP) on bovine humoral and cellular responses to a soluble protein extract of gamma irradiated Brucella abortus strain 19 (SPEBA) were investigated. Thirty-five beef steers were randomly allotted to nine groups. Three of these groups received SPEBA (2 mg protein per dose) subcutaneously in combination with adjuvants, one group received the reduced dose of B. abortus strain 19 (S19), and one group received SPEBA alone. Controls included groups receiving adjuvant preparations only or no vaccine. Immune responses to the various immunizations were assessed sequentially for 56 days using various in vitro and in vivo assays. The humoral response to B. abortus was measured using standard serologic tests, an enzyme-linked immunosorbent assay, and a quantitative fluorometric immunoassay. The cell-mediated immune (CMI) response was measured by antigen-specific lymphoproliferation (LP), interleukin 2 (IL 2) production, and soluble suppressor factor release. Skin testing at day 35 for delayed-type hypersensitivity (DTH) to SPEBA was also performed. Minimal humoral responses were induced with SPEBA alone. The highest and most sustained serum antibody responses to B. abortus antigens were elicited by the S19 vaccine. A combination of SPEBA with DDA + TDM induced higher antibody levels than SPEBA with DDA or SPEBA with DDA + MDP. Responses to DTH among the groups receiving SPEBA were most notable in the SPEBA with DDA + TDM groups. Increased IL 2 production was greatest in the S19 and SPEBA with DDA + TDM vaccinates. The results indicated that a combination of DDA + TDM best potentiated immune responses to a soluble B. abortus antigen preparation and may be useful as adjuvants for future vaccines.  相似文献   

16.
人参皂甙Rb1的免疫佐剂作用   总被引：20，自引：0，他引：20  
分别将人参皂甙Rbl(人参主要成分之一)以及氢氧化铝胶作为佐荆和金黄色葡萄球菌菌体抗原混合免疫豚鼠，观察免疫前后血清抗体滴度变化；并用Rbl和奶牛乳房炎金黄色葡萄球菌疫苗混合免疫奶牛，观察免疫前后血清抗体滴度变化，以及血液淋巴细胞在刀豆蛋白A(ConA)、美洲商陆(PWM)和金黄色葡萄球菌抗原刺激下的体外细胞增殖反应。结果表明，Rbl和抗原混合物免疫动物后，未见任何不良反应；Rbl组豚鼠血清抗体滴度比对照组和氢氧化铝胶佐剂组滴度增加快，幅度显著增高；Rbl组奶牛血清抗体滴度比对照组奶牛显著增加，ConA、PWM和金黄色葡萄球菌抗原诱导的血液淋巴细胞体外细胞增殖反应比对照组显著提高。因此，Rbl是一种有效的免疫佐剂。  相似文献   

17.
A concentration of 2.5 X 10(-5) M 2-mercaptoethanol (2-ME) added to the medium in lymphocyte blastogenesis assays increased both the uptake of [3H]thymidine in unstimulated lymphocyte cultures and the probability of detecting antigen-sensitized cattle. The use of 2-ME did not cause lymphocytes from unsensitized cattle to react positively in blastogenesis assays. A crude brucella lysate prepared from Brucella abortus strain 19 was compared with a well-characterized brucella protein allergen prepared from B melitensis and was found to be equally suitable for use in blastogenesis assays. Cell-mediated immunity was produced most effectively in 4-month-old calves by tetanus toxoid, then by Mycobacterium bovis, and least effectively by B abortus.  相似文献   

18.
A competitive enzyme-linked immunosorbent assay (ELISA) using a monoclonal antibody conjugated to horseradish peroxidase MA(A) and a complement fixation test (CFT) were applied to sera collected over a two-year period from 60 cattle challenged with Brucella abortus strain 544. Forty-eight of the cattle were previously vaccinated with B. abortus strain 19 (S19) or B. abortus strain 45/20 (45/20). After challenge 33 of the cattle remained uninfected and nine of the 27 infected cattle showed aberrant reactions by the CFT. The performance of the MA(A) ELISA was as follows: after vaccination, the MA(A) ELISA, like the CFT, was unable to differentiate infected cattle from those recently vaccinated with S19. After challenge the MA(A) ELISA gave results comparable with the CFT for those cattle with aberrant reactions. For the non-infected cattle there was a similar number of weeks after challenge when both tests were negative. It is suggested that the main advantage of the MA(A) ELISA when compared with the CFT lies in its relatively simple test procedure.  相似文献   

19.
The effect of sublethal concentrations of the Pasteurella haemolytica leukotoxic culture supernate on bovine lymphocyte blastogenesis was investigated. Blastogenesis in cultures stimulated with either concanavalin A (Con A) or pokeweed mitogen (PWM) was inhibited in the presence of the supernate, as was the response to purified protein derivative in lymphocytes from BCG-vaccinated cattle. Partially purified leukotoxin had a similar effect. Pre-incubation of the leukotoxic supernate with a polyclonal rabbit antiserum raised to the immunogenic molecule of recombinant leukotoxin (r LktA) abrogated this effect, implicating leukotoxin as the factor responsible for the inhibition. B cell enriched cultures tended to be more sensitive to leukotoxic effects than did T cell enriched cultures. Although only ruminant cells are susceptible to the lethal effects of P. haemolytica leukotoxin, the toxin did inhibit both Con A- and PWM-induced proliferation of human and dog lymphocytes. As well, at high leukotoxin doses, Con A-stimulated pig lymphocyte proliferation was reduced. Rabbit lymphocytes were not affected by leukotoxin in either Con A- or PWM-stimulated cultures.  相似文献   

20.
Brucella abortus strain 19 salt-extractable proteins fractionated by differential ammonium sulfate precipitation were used in a western blotting method to detect bovine immunoglobulin G antibodies to B. abortus. Sera from infected cattle and from cattle vaccinated with strain 19 and subsequently exposed to virulent B. abortus bound to a common group of antigens ranging in molecular weights from 31,000 to 45,000 daltons. Immunoglobulin G antibodies in sera from the latter group in addition also bound to antigens with molecular weights of 66,000 to 71,000 daltons. Some sera from cattle vaccinated when sexually mature reacted similar to those from infected cattle, while immunoglobulin G antibodies in sera from Brucella-free cattle and vaccinated calves did not bind to either group of antigens. In general, fractionation of the proteins by ammonium sulfate precipitation offered no advantage for detecting differences between groups of sera. Ammonium sulfate fraction 0 to 35% reacted with a larger number of sera from a naturally infected group than fraction 0 to 70%. Both fractions reacted equally well with sera from the other groups of cattle, while fractions 35 to 70% and 70 to 100% reacted poorly in this technique. The attractive feature of the blot is that sera from calfhood-vaccinated cattle did not react.  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