| دانلود رایگان مقاله انگلیسی + خرید ترجمه فارسی
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| عنوان فارسی مقاله: |
واکسن برعلیه هلیکوباکتر پیلوری: حقیقت یا افسانه؟ |
| عنوان انگلیسی مقاله: |
Vaccine against Helicobacter pylori: fact or fiction? |
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| مشخصات مقاله انگلیسی (PDF) | |
| سال انتشار مقاله | 1997 |
| تعداد صفحات مقاله انگلیسی | 3 صفحه با فرمت pdf |
| رشته های مرتبط با این مقاله | پزشکی و زیست شناسی |
| گرایش های مرتبط با این مقاله | گوارش و کبد، میکروبیولوژی و ایمنی شناسی پزشکی |
| مجله مربوطه | international peer-reviewed journal for health professionals and researchers in gastroenterology & hepatology |
| دانشگاه تهیه کننده | بخش گوارش، دانشکده پزشکی هاروارد، بوستون، ایالات متحده |
| رفرنس | دارد |
| لینک مقاله در سایت مرجع | لینک این مقاله در سایت NCBI |
| نشریه | NCBI |
| مشخصات و وضعیت ترجمه فارسی این مقاله (Word) | |
| تعداد صفحات ترجمه تایپ شده با فرمت ورد با قابلیت ویرایش و فونت 14 B Nazanin | 7 صفحه |
- فهرست مطالب:
آیا نیاز است؟
واکسیناسیون H pylori چه دستاوردهایی حاصل شده است؟
واکسیناسیون H pylori چه کاری مانده که باید انجام داد؟
- بخشی از ترجمه:
واکسیناسیون H pylori : چه کاری مانده که باید انجام داد؟
طبق مطالعات جانوری، ایمن سازی موکوسی، که باعث تحریک سیستم ایمنی موکوسی می شود، پیش نیازی برای حفاظت به نظر می رسد. مدارک انسانی محدودی از این مفهوم حمایت می کند، اما نشان می دهد سطح تحریک سیستم ایمنی در انسانهایی با اورئاز به علاوه LT بسیار پائین بوده و منجر به رفع عفونت می گردد. برای دستیابی به ایمنی حفاظتی در انسانها، این احتمال وجود دارد که به بیش از یک آنتی ژن نیاز باشد، و اینکه مد تحریک سیستم ایمنی موکوسی بایدبهبود یابد.
در رابطه با تهیه و آماده سازی آنتی ژن بکاررفته برای ایمن سازی، ارتباط دو یا سه آنتی ژن، پاسخ ایمنی قویتری نسبت به استفاده از یک آنتی ژن استنباط می کند. در موش ها، واکسن متشکل از HspA و زیرواحد B از اورئاز، سطح بالاتری از حفاظت در برابر H felis نسبت به هر آنتی ژن تجویز شده به تنهایی را القا و تحریک نمود. با ترکیبی از سیتوتوکسین VacA و اورئاز در موش های آلوده به H pylori نتایج مشابهی بدست آمد. برای بهبود کارایی واکسن و رفع محدودیت ایمونوبیولوژیکی ممکن، به ترکیبی از آنتی ژن ها نیاز می باشد. این پدیده، که اخیراً در موشها تشخیص داده شده است، در انسانها رخ داده و با واکسن تهیه شده از بیش از یک آنتی ژن از آن جلوگیری خواهد شد.
- بخشی از مقاله انگلیسی:
H pylori vaccination: what has been achieved? The concept that vaccination was possible came from animal studies which showed that protection against various gastric helicobacter species could be achieved by mucosal immunisation using an antigen and a mucosal adjuvant. The initial studies were performed using whole cell extracts of bacteria and showed that vaccination was possible despite the lack of eYcacy of the natural immune defences of the host against infection with H pylori.13 14 However, vaccines based on uncharacterised antigen preparations of H pylori are associated with high production costs, diYculties of standardisation, and a high potential for side effects. For these reasons, eVorts have been focused primarily on the identification of antigens of H pylori able to confer protection. Several protective antigens have been identified, including urease, the cytotoxin VacA, two heat shock proteins (HspA and HspB), and catalase.15–18 The list of protective antigens is still growing, and the availability in the public domain of the entire H pylori genome will certainly facilitate the identification of more vaccine antigens. Urease is currently the most promising candidate, and its value as a vaccine antigen has been confirmed by numerous studies in mice, ferrets, and non-human primates.17 19 20 Urease conferred protection against helicobacter infection when delivered either as a native protein or as an enzymatically inactive recombinant protein.15 In addition, when mice previously infected with H felis were immunised with H pylori urease, their infection cleared.21 This therapeutic eVect of mucosal immunisation has also been observed in mice immunised with a bacterial lysate of H felis and with H pylori cytotoxin.22 Therapeutic immunisation with urease has recently been reported in ferrets naturally infected with H mustelae. 19 Infection with H mustelae occurs in ferrets soon after weaning, persists for life, induces active chronic gastritis, and is associated with the development of ulceration in a subgroup of infected animals.23 Thus, therapeutic immunisation is possible in a natural setting of helicobacter infection, confirming that the inability of the natural immune response to clear helicobacter infection can be overcome. In addition to conferring protection, vaccine antigens should, in theory, have a number of other important characteristics. The antigen should be shared by all H pylori isolates without much antigenic variation, and should lack intrinsic toxicity. According to these criteria, the cytotoxin VacA, which is not expressed by all strains and induced erosions when fed to mice, may not be an ideal vaccine candidate.24 There is also concern about inducing an immune response to HspB because this protein has homologies to the GroEL family of heat shock proteins16 Leading articles express the views of the author and not those of the editor and editorial board. 728 Gut 1997; 41: 728–730 involved in autoimmune reactions.25 In contrast, urease and HspA are expressed by all H pylori strains and do not induce adverse reactions when administered orally with an adjuvant to mice. Urease is also safe when administered to non-human primates.20 Immunisation with urease has been studied recently in H pylori infected human volunteers. It was found that oral administration of urease alone did not induce systemic adverse reactions and did not modify H pylori mediated gastric mucosal inflammation.26 Urease alone, however, induced no changes in the host immune response to H pylori or in the density of bacteria present on the gastric mucosa, underlining the need for an appropriate mucosal adjuvant. More recently, the safety and immunogenicity of recombinant H pylori urease was tested when given with a mucosal adjuvant, the heat labile enterotoxin (LT) of Escherichia coli. This study confirmed the safety of urease. Urease given with LT induced an immune response and a reduction in the density of gastric H pylori infection, an indication that vaccination may lead to cure of human H pylori infection. H pylori vaccination: what remains to be done? From animal studies, mucosal immunisation resulting in stimulation of the mucosa associated immune system seems to be a prerequisite for protection. The limited human evidence supports this concept, but suggests that the level of stimulation of the immune system obtained in humans with urease plus LT is too low to lead to clearance of the infection.27 To obtain protective immunity in humans, it is likely that more than one antigen will be required, and that the mode of stimulation of the mucosal immune system will have to be improved. With regard to the antigen preparation used for immunisation, an association of two or three antigens may elicit a stronger immune response than the use of a single antigen. In mice, a vaccine preparation composed of HspA and the B subunit of urease induced a higher level of protection against H felis than either antigen given alone.16 Similar results were reported with a combination of VacA cytotoxin and urease in H pylori infected mice.
| دانلود رایگان مقاله انگلیسی + خرید ترجمه فارسی
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| عنوان فارسی مقاله: |
حقیقت کشف واکسن بر ضد عفونت هلیکوباکتر پیلوری |
| عنوان انگلیسی مقاله: |
Vaccine against Helicobacter pylori: fact or fiction? |
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