점액성 면역체계는 외부환경에 민감한 신체부분을 보호하는 분화된 림프조직들로 구성되어있다. 특히 위관련 림프조직은 이 면역체계의 중추적 역활을 하며 체조직중에서 가장 많은 림파구들이 존재하는 곳이다. 그러나, 수용성 단백질 항원을 경구투여할 경우 관웅작용으로 인한 전신성, 점액성 면역작용의 관용을 가져오는 겅우가 많다. "관용"을 극복하는 일완으로 cholera toxin, ISCOMS같은 면역보조제를 사용하여 전체적인 면역기관을 활성화시켜 항원감작에 대해 민감하도록 하거나 항원이 중간에 대사되거나 분해됨이 없이 원활히 항원가공세포에 표적될 수 있도록 전달시스템에 리포좀이나 미세담립체의 개발을 이용하는 방법들이 많은 연구실에서 행해져 오고 있다. 항원전달에 가장 성공적으로 행해지고 었는 것은 pH에 대한 안정성이 뛰어난 ...
점액성 면역체계는 외부환경에 민감한 신체부분을 보호하는 분화된 림프조직들로 구성되어있다. 특히 위관련 림프조직은 이 면역체계의 중추적 역활을 하며 체조직중에서 가장 많은 림파구들이 존재하는 곳이다. 그러나, 수용성 단백질 항원을 경구투여할 경우 관웅작용으로 인한 전신성, 점액성 면역작용의 관용을 가져오는 겅우가 많다. "관용"을 극복하는 일완으로 cholera toxin, ISCOMS같은 면역보조제를 사용하여 전체적인 면역기관을 활성화시켜 항원감작에 대해 민감하도록 하거나 항원이 중간에 대사되거나 분해됨이 없이 원활히 항원가공세포에 표적될 수 있도록 전달시스템에 리포좀이나 미세담립체의 개발을 이용하는 방법들이 많은 연구실에서 행해져 오고 있다. 항원전달에 가장 성공적으로 행해지고 었는 것은 pH에 대한 안정성이 뛰어난 생분해성 미세담립체로 DL-PLG(DL-lactide-co-glycolide)가 널리 알려져 있으나 이러한 것들은 제조과정중에 유기용매처리가 반드시 필요한 공정중하나이므로 포집되는 단백질의 안정성과 투여 후 안전성에 의문을 제기하지 않을 수 없다. 본 실험에 이용한 liposome는 가열처리가 과정이 들어있으나 포집되는 단백질에 대해 안정성이 확인이 되었으며 간단한 처리과정만을 거치므로 별다른 위해물질이 없다는 장점을 가진다. "관용"작용의 원인으로 가장 크게 토의되고 있는 것으로는 위산액에서 의 낮은 pH와 소화효소들의 작용을 들 수 있다. 특히 산에 대한 안정성이 "관용"작용을 억제하는 주요 표적이다. 이에 대해 본 실험에서는 일반적인 구조를 가지고 있으며 특히 쥐에서 관용작용을 일으킨다고 이미 보고된 바가 있어 면역보조제 실험에서 대상항원으로서의 가치에 의문이 제기되어오고 있는 ovalbumin을 리포좀에 포집하여 경구투여한 결과 특이적인 항체생성을 유발시킴으로써 리포좀 포집이 장내 면려기관에 성공적으로 표적되었음을 보였다. 따라서 항원성이 떨어지는 수용성 단백질에대한 전달체로서의 가능성을 보이며 짧은 제조과정으로 개별항원에 따른 선별적인 제조도 가능하다. 결과적으로 리포좀에 포집된 항원은 구강을 통해 점액성 면역뿐아니라 전신면역에도 효과적으로 작용하였다. 그러나 차후에 좀 더 장시간 위산에서 안정하며 천천히 일정량을 간헐적으로 용출할 수 있도록 carrier formulation 조정에 변수를 가해야 하는 일과 항체역가 외에 장내 림프구의 80%를 차지하는 intraepithelial T lymphocyte에 대한 영향, 비특이면역작용을 하는 장관세포들에서 분비되는 라디칼의 fluctuation, neutralization effect에 대해서 좀더 상세한 실험이 이루어져야한다.
점액성 면역체계는 외부환경에 민감한 신체부분을 보호하는 분화된 림프조직들로 구성되어있다. 특히 위관련 림프조직은 이 면역체계의 중추적 역활을 하며 체조직중에서 가장 많은 림파구들이 존재하는 곳이다. 그러나, 수용성 단백질 항원을 경구투여할 경우 관웅작용으로 인한 전신성, 점액성 면역작용의 관용을 가져오는 겅우가 많다. "관용"을 극복하는 일완으로 cholera toxin, ISCOMS같은 면역보조제를 사용하여 전체적인 면역기관을 활성화시켜 항원감작에 대해 민감하도록 하거나 항원이 중간에 대사되거나 분해됨이 없이 원활히 항원가공세포에 표적될 수 있도록 전달시스템에 리포좀이나 미세담립체의 개발을 이용하는 방법들이 많은 연구실에서 행해져 오고 있다. 항원전달에 가장 성공적으로 행해지고 었는 것은 pH에 대한 안정성이 뛰어난 생분해성 미세담립체로 DL-PLG(DL-lactide-co-glycolide)가 널리 알려져 있으나 이러한 것들은 제조과정중에 유기용매처리가 반드시 필요한 공정중하나이므로 포집되는 단백질의 안정성과 투여 후 안전성에 의문을 제기하지 않을 수 없다. 본 실험에 이용한 liposome는 가열처리가 과정이 들어있으나 포집되는 단백질에 대해 안정성이 확인이 되었으며 간단한 처리과정만을 거치므로 별다른 위해물질이 없다는 장점을 가진다. "관용"작용의 원인으로 가장 크게 토의되고 있는 것으로는 위산액에서 의 낮은 pH와 소화효소들의 작용을 들 수 있다. 특히 산에 대한 안정성이 "관용"작용을 억제하는 주요 표적이다. 이에 대해 본 실험에서는 일반적인 구조를 가지고 있으며 특히 쥐에서 관용작용을 일으킨다고 이미 보고된 바가 있어 면역보조제 실험에서 대상항원으로서의 가치에 의문이 제기되어오고 있는 ovalbumin을 리포좀에 포집하여 경구투여한 결과 특이적인 항체생성을 유발시킴으로써 리포좀 포집이 장내 면려기관에 성공적으로 표적되었음을 보였다. 따라서 항원성이 떨어지는 수용성 단백질에대한 전달체로서의 가능성을 보이며 짧은 제조과정으로 개별항원에 따른 선별적인 제조도 가능하다. 결과적으로 리포좀에 포집된 항원은 구강을 통해 점액성 면역뿐아니라 전신면역에도 효과적으로 작용하였다. 그러나 차후에 좀 더 장시간 위산에서 안정하며 천천히 일정량을 간헐적으로 용출할 수 있도록 carrier formulation 조정에 변수를 가해야 하는 일과 항체역가 외에 장내 림프구의 80%를 차지하는 intraepithelial T lymphocyte에 대한 영향, 비특이면역작용을 하는 장관세포들에서 분비되는 라디칼의 fluctuation, neutralization effect에 대해서 좀더 상세한 실험이 이루어져야한다.
The development of new vaccine, both more efficacious, easier to deliver and less expensive , has become an area of research that can certainly benefit from recent techinical development. In the production of safe subunit and systhetic small peptide vaccines, these vaccines are weakly or non-immunog...
The development of new vaccine, both more efficacious, easier to deliver and less expensive , has become an area of research that can certainly benefit from recent techinical development. In the production of safe subunit and systhetic small peptide vaccines, these vaccines are weakly or non-immunogenic and cannot, therefore, be used effectively in the absence of immunological adjuvants(agents that can induce strong immunity to antigens) In many developing countries the drop-out rates from individuals receiving the first dose, but not successive doses is high and can reach 70%. The reasons for these drop-out rates are numberous: unavailabiliy of vaccines, difficulty of access, ignorance on the fact that some vaccines require multiple doses, lack of faith in vaccination, fear of side-effects. Taking these considerations into account, liposomes have been widely used as carriers of protein or peptide antigens. Antigenic materials can be attatched to the outer surface, encapsulated within the internal aqueous spaces, or reconstituted within the lipid bilayers of the liposomes. The natural tendency of liposomes to interact with macrophages has served as the primary rationale for utilizing liposomes as carriers antigens. liposome are successful for inducing potent immunity in vivo and they are now being employed in numerous immunization procedures and as vehicles for candidate vaccines. Until recently, liposome technology has been concerned with vesicles composed of phospholipid. However, phospholipid liposomes have certain limitations such as sensitivity to host phospholipases, instability on storage, high cost of manufacture and difficulty in scale up of production. For these reasons there has been increasing interest in nonphospholipid liposomes composed of "membrane mimetic" amphiphiles which are molecules with a hydrophilic head group attached to a hydrophobic tail. Liposomes have also been widely proposed as carriers for oral immunization, both for inducing local secretory IgA antibodies and for inducing serum antibodies. Induction of local mucosal IgA is important for protection against pathogenic microorganisms that invade via mucosal surfaces^(47)) Oral immunizations can induce detectable levels of seretory IgA In distant ites via migration of B lymphoblasts. To induce a mucosal immune response, antigens must be transported across the epithelial barrier by specialized epithelial M cells present only over the lymphoid follicles of mucosal inductive sites. M cell uptake of soluble antigens is general]y poor, but particulate antigens, especially those that can adhere to the mucosa, tend to be efficient mucosal vaccines, in part beacause they are taken up by M cells_(49)). Thus, soluble antigens have been formulated in or on various particulate carriers for oral delivery. Liposomes containing encapsulated antigens induced a moderate increase in specific secretory IgA when admistered via oral routes. Therefore, in this study, we have used nonphospholipid liposome and protein cocheleate containing adjuvanticity and carrier of OVA, Pseudomonas aeruginosa membrane protein for oral vaccine candidate, Nonphospholipid liposomes^(50)) and protein cocheleaate^(15)) were prepared essentially as described elsewhere. Groups of male BALB/C were immunized orally by 4 times feeding, interval 7 days. Mucosal secretions and sera of immunized mice were collected at sacrifice. Blood sample were collected by cardiac puncture. Mice were then sacrificed by cervical dislocation, the abdominal cavidity was opened, and the entire samll intestine was removed. IgG, IgA antibodies were measured by ELISA. In the presence of liposome, the IgA response to antigen was further enhanced. Although immunized through oral route, systemic IgG was enhanced. One interpretation of our results is that inclusion of antigen in liposomes provided a modest increase in the amount of antigen delivered to cells in mucosal lymphoid tissues, perhaps by providing a particulate package of concentrated antigen that was readily endocytosed by M cells. Liposomes are taken up from the lumen of the intestine into organised mucosal lymphoid tissues such as Peyer's patches. It is generally agreed that such uptake depends on the transepithelial transport activity of M cells and that adherence to M cell surfaces can greatly enhance the efficiency of transport. The lack of information about the composition of M cell membranes has hampered efforts to target particles to M cells. But this study provides the evidence that IgA mediated M cell transport of an antigen-containing liposome can indeed lead to enhancement of the mucosal immune response. Since this oral immunization route can also result in IgA secretions in intestine. It could be a useful method for mucosal immunization for oral vaccine candidate.
The development of new vaccine, both more efficacious, easier to deliver and less expensive , has become an area of research that can certainly benefit from recent techinical development. In the production of safe subunit and systhetic small peptide vaccines, these vaccines are weakly or non-immunogenic and cannot, therefore, be used effectively in the absence of immunological adjuvants(agents that can induce strong immunity to antigens) In many developing countries the drop-out rates from individuals receiving the first dose, but not successive doses is high and can reach 70%. The reasons for these drop-out rates are numberous: unavailabiliy of vaccines, difficulty of access, ignorance on the fact that some vaccines require multiple doses, lack of faith in vaccination, fear of side-effects. Taking these considerations into account, liposomes have been widely used as carriers of protein or peptide antigens. Antigenic materials can be attatched to the outer surface, encapsulated within the internal aqueous spaces, or reconstituted within the lipid bilayers of the liposomes. The natural tendency of liposomes to interact with macrophages has served as the primary rationale for utilizing liposomes as carriers antigens. liposome are successful for inducing potent immunity in vivo and they are now being employed in numerous immunization procedures and as vehicles for candidate vaccines. Until recently, liposome technology has been concerned with vesicles composed of phospholipid. However, phospholipid liposomes have certain limitations such as sensitivity to host phospholipases, instability on storage, high cost of manufacture and difficulty in scale up of production. For these reasons there has been increasing interest in nonphospholipid liposomes composed of "membrane mimetic" amphiphiles which are molecules with a hydrophilic head group attached to a hydrophobic tail. Liposomes have also been widely proposed as carriers for oral immunization, both for inducing local secretory IgA antibodies and for inducing serum antibodies. Induction of local mucosal IgA is important for protection against pathogenic microorganisms that invade via mucosal surfaces^(47)) Oral immunizations can induce detectable levels of seretory IgA In distant ites via migration of B lymphoblasts. To induce a mucosal immune response, antigens must be transported across the epithelial barrier by specialized epithelial M cells present only over the lymphoid follicles of mucosal inductive sites. M cell uptake of soluble antigens is general]y poor, but particulate antigens, especially those that can adhere to the mucosa, tend to be efficient mucosal vaccines, in part beacause they are taken up by M cells_(49)). Thus, soluble antigens have been formulated in or on various particulate carriers for oral delivery. Liposomes containing encapsulated antigens induced a moderate increase in specific secretory IgA when admistered via oral routes. Therefore, in this study, we have used nonphospholipid liposome and protein cocheleate containing adjuvanticity and carrier of OVA, Pseudomonas aeruginosa membrane protein for oral vaccine candidate, Nonphospholipid liposomes^(50)) and protein cocheleaate^(15)) were prepared essentially as described elsewhere. Groups of male BALB/C were immunized orally by 4 times feeding, interval 7 days. Mucosal secretions and sera of immunized mice were collected at sacrifice. Blood sample were collected by cardiac puncture. Mice were then sacrificed by cervical dislocation, the abdominal cavidity was opened, and the entire samll intestine was removed. IgG, IgA antibodies were measured by ELISA. In the presence of liposome, the IgA response to antigen was further enhanced. Although immunized through oral route, systemic IgG was enhanced. One interpretation of our results is that inclusion of antigen in liposomes provided a modest increase in the amount of antigen delivered to cells in mucosal lymphoid tissues, perhaps by providing a particulate package of concentrated antigen that was readily endocytosed by M cells. Liposomes are taken up from the lumen of the intestine into organised mucosal lymphoid tissues such as Peyer's patches. It is generally agreed that such uptake depends on the transepithelial transport activity of M cells and that adherence to M cell surfaces can greatly enhance the efficiency of transport. The lack of information about the composition of M cell membranes has hampered efforts to target particles to M cells. But this study provides the evidence that IgA mediated M cell transport of an antigen-containing liposome can indeed lead to enhancement of the mucosal immune response. Since this oral immunization route can also result in IgA secretions in intestine. It could be a useful method for mucosal immunization for oral vaccine candidate.
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