초록 ▼

본 과제에서는 암환자에게서 저하된 NK 면역기능의 구체적인 원인을 밝히고 이를 바탕으로 NK 면역세포의 기능을 활성화 시켜 궁극적으로 종양면역치료의 바탕이 될 세포 분자적 기전을 제시하였음. 이를 위하여 암세포를 사멸시키는데 주요한 역할을 하는 세포수용체 NKG2D를 활성화 시키기 위해 여러 암세포주에 NKG2D 리간드발현을 조절하여 NK세포가 암세포주를 완벽하게 사멸 시킬 수 있는 조건을 확립하였음. 또한 NK세포 간에 발현하고 있는 2B4 수용체와 CD48 리간드간의 상호작용에 의해 NK세포의 활성이 조절된다는 사실을 밝히고 이

본 과제에서는 암환자에게서 저하된 NK 면역기능의 구체적인 원인을 밝히고 이를 바탕으로 NK 면역세포의 기능을 활성화 시켜 궁극적으로 종양면역치료의 바탕이 될 세포 분자적 기전을 제시하였음. 이를 위하여 암세포를 사멸시키는데 주요한 역할을 하는 세포수용체 NKG2D를 활성화 시키기 위해 여러 암세포주에 NKG2D 리간드발현을 조절하여 NK세포가 암세포주를 완벽하게 사멸 시킬 수 있는 조건을 확립하였음. 또한 NK세포 간에 발현하고 있는 2B4 수용체와 CD48 리간드간의 상호작용에 의해 NK세포의 활성이 조절된다는 사실을 밝히고 이를 근거로 하여 2B4와 NKG2D의 synergy역할을 중점으로 마우스 암 모델과 정상인, 암환자에게서 연구하여 NK세포의 활성극대화에 요구되는 조건을 확립하였음. 또한 이들 수용체들이 Synergy를 일으키는 메카니즘 및 신호전달 기작을 연구하였음. 이러한 결과는 면역학적질환전반에 응용될 수 있는 기반지식을 제시하여 난치성질환의 치료에 기여하리라 사료됨.

Abstract ▼

I. Purpose
In theory, tumor cells are recognized as foreign, thus have full potential to be lysed by cells in the immune system. However, tumors have evolved to learn how to escape our immune system, and devoid of attack from our immune cells. Therefore, it is critical to understand the mechanism

I. Purpose
In theory, tumor cells are recognized as foreign, thus have full potential to be lysed by cells in the immune system. However, tumors have evolved to learn how to escape our immune system, and devoid of attack from our immune cells. Therefore, it is critical to understand the mechanism of immune escape by tumors, and develop a strategy to overcome immune suppression by tumor. Natural Killer(NK)cells are strong candidate for anti-tumor immunotherapy as they can lyse tumor cells without prior sensitization and antigen requirement. Thus, it would be critical to understand the mechanistic basis of NK cell activation for the application to the specific novel immunotherapies to treat patients suffering from cancer.
II .Goals and Objectives
To understand the mechanism of NK cell activation, we searched NK cell surface receptors involved in lysing tumor cells. One strong candidate is NKG2D, which binds its ligand NKG2DL (Rae-lg or H-60) on tumor cells and lyse. Since our preliminary data suggest that NK cell activity is also controlled by homotypic NK-NK interaction through 2B4 and CD48. we explored if these two receptors function to synergize NK cell activation. for this purpose, we set our specific aims as follows.
-Establishment of soluble and solid tumor lines expressing murine NKG2DL (Rae-1g and H-60).
-Screening of NK receptors regulated by 284 and investigate their signaling mechanism.
-Examination of tumor forming ability by NKGD2L expressing tumor cells in WT or 2B4KO mice.
-Characterization of role of 2B4 in the process of tumor formation, by performing CTL assay, cytokine ELISA, thymidine incorporation Assay.
-Investigation of NKG2D and 2B4 function in healthy human subjects as well as cancer patients.
III. Results.
-Achievement of full NK cell activation through NKG20 as revealed by increased lytic ability against NKG2DL-expressing tumor targets.
-Establishment of stable NKG2DL-expressing cell line (low, intermediate, and high NKG2DL expressor)
-Identification of regulating role of 284 in NK cell activation stimulated by NKG2D.
-2B4 interaction with CD48 expressed on tumor target suppressed proximal signal transduction initiated from NKG2D. Thus, 2B4 ligation inhibited Calcium influx and MAP kinase activation in response to tumor target exposure.
-In vivo, tumor cells expressing CD48 are less killed by WT NK cells and lead to formation of tumors more easily. In the absence of 2B4, CD48+ tumor cells are better killed by WT NK cells, thus confirming the inhibitory role of 284 in the tumor formation.
-These data are in line with the notion that 2B4 was able to suppress the function of NKG2D in vivo.
-To further confirm the inhibitory role of 2B4 in human, CD48 expressing K562 tumor targets are generated by cloning human CD48 into K562 cell line.
-In contrast to the inhibitory role of 2B4 in mouse, CD48+K562 tumor cells are better lysed by human NK cells. These data indicate that 2B4 is an activating receptor in Human.
-The activating role of 2B4 was further confirmed in NK cells purified from human cancer patients.
I. Contribution to the Science and Technology
Completion of our research has revealed a previously undiscovered mechanism of NK cell activation; interplay between NK cell receptor 2B4 and NKG2D. This interplay results an inhibition in the mouse while it causes activation in human. These findings can often lead mis-interpretation of mouse data and causes deviation from pre-clinical data. Our data strong1y demonstrate that the process of NK cell activation needs to be carefully monitored and chosen to be utilized for specific immune cell therapy.
We believe that these findings will provide a mechanistic basis of NK cell activation, and contribute tremendously in the filed of tumor immunology. In addition, it will provide shed light into the new generation of immune regulation and immunotherapy for the cancer as well as other immune-related diseases.

목차 Contents

• 표지...1
• 2. 제출문...2
• 3. 보고서 요약서...3
• 4. 요약문(한글)...4
• 5. 요약문(영문)...6
• 6. 연구 성과 실적 및 향후 계획 ...8
• 7. 참여연구원 현황표...28
• 목차...30
• I. 총괄현황...31
• 2. 제출문...32
• 3. 보고서 요약서...33
• 4. 요약문(한글)...34
• 5. 요약문(영문)...36
• 6. 연구 성과 실적 및 향후 계획...38
• 7. 참여연구원 현황표...40
• II. 총괄연구과제 연구결과...41
• 1. 연구개발과제의 배경 및 필요성...42
• 2. 국내외 기술개발 현황...49
• 3. 연구개발과제의 추진체계...50
• 4. 연구개발 수행 내용 및 결과...51
• 5. 목표달성도 및 관련분야 기여도...62
• 6. 향후 연구성과 추진계획(※해당되는 경우만 작성)...63
• 7. 연구개발결과의 파급효과...63
• 8. 연구개발결과의 활용계획...64
• 9. 연구개발과정에서 수집한 해외과학기술정보...64
• 10. 참고문헌...64
• IV. 첨부서류...66
• 2. 연구성과 실적 증빙서류...70
• 3. 기타 요청서류...70