Regulation of Innate Immunity via MHC Class II-mediated Signaling; Non-classical Role of MHC Class II in Innate Immunity

Park, Hye-Lim,Nam, Jae-Hwan 대한미생물학회 2011 Journal of Bacteriology and Virology Vol.41 No.3

자연면역반응(innate immune response)은 병원체의 침입 을 막는 첫 번째 방어선으로 알려져 있으며, 이는 병원균의 독특한 분자적 특징을 인식할 수 있는 Toll-유사 수용체(Toll-like receptor, TLR), Nod-유사 수용체 및 RIG I-유사 수용체를 통해 작용하게 된다. 병원체를 인식한 Toll-유사 수용체의 활성화는 세포 내 연쇄반응을 통해 염증성 사이토카인(inflammatory cytokine)을 생성시키고, 항 원제시세포(B 세포, 수지상세포, 대식세포)의 보조인자 (costimulatory molecule)의 발현을 촉진하여 결과적으로 침입한 병원균을 제거하는데 필수적이다. Major histocompatibility complex (MHC) class II는 항원제거를 위해 항원제시과정에 참여하는 것 이외에도 세포의 증식 및 성숙, 세포사멸에도 관여하는 것으로 알려져 있으나, 본 논문에서는 TLR 매개 신호전달과정에서 MHC class II가 새로운 중요한 조절 요소로 작용함을 확인하여 MHC class II의 새로운 기능에 주안점을 두어 서술하고 있다. Liu 등은 MHC class II가 결핍된 마우스에 병원체가 감염되면 친염증성 사이토카인(proinflammatory cytokine)을 비롯한 type I interferon의 생성이 감소할 뿐만 아니라, 병 원체 감염에 의한 endotoxin shock 또한 감소하는 것을 통해 MHC class II와 TLR 매개 면역반응의 관련성을 증명하였다. 이어 세포표면에 발현하는 MHC class II가 아닌 세포 내 endosome에 위치하는 세포질(intracellular) MHC class II가 보조인자(costimulatory molecule)인 CD40을 통 해 Btk와 상호작용을 하고, 이는 최종적으로 MyD88 및 TRIF와 상호작용을 함으로써 TLR 매개 신호전달을 촉진시킨다는 것을 증명하였다. 이러한 결과는 MHC class II의 새로운 기능을 제시함과 동시에 자연면역반응과 획득면역반응이 서로 밀접한 관계에 놓여 있음을 시사하고 있다. MHC class II has long been known to play a classical role in antigen presentation and to act as a signal transducer capable of inducing the adaptive immunity needed to produce pathogen specific antibodies. However, it has recently been revealed that MHC class II can also promote the activation of Toll-like receptor mediated signaling by functioning as an adapter. This means that in addition to its classical function of adaptive immunity, MHC class II also plays an intriguing role in the mechanisms that regulate innate immunity. That being the case, queries inevitably arise regarding the fact that many pathogens have tried to control the induction of MHC class II so as to escape the host immune response. Liu et al (Nat Immunol 2011;12:416-424) demonstrated that intracellular MHC class II interacted with Btk, and that this activated Btk promoted TLR signaling via Myd88 and TRIF. The results of this study provide insight regarding the possibility of a novel role for MHC class II, which was heretofore regarded solely as a classical molecule involved in adaptive immune responses, as a regulator of innate immune responses.

흰쥐 뇌에 분포하는 MHC Class II 양성 면역반응 수지상세포의 연령에 따른 변화

양필순(Pil Soon Yang),황규근(Kyu Geun Hwang),유기수(Ki Soo Yoo) 대한소아신경학회 2002 대한소아신경학회지 Vol.10 No.1

목적: 항원제공세포인 MHC Class II 양성 면역반응성 수지상세포를 두개강내에 투여하여 종양을 치료하는 방법이 제시되어 수지상세포에 대한 관심이 고조되고 있다. 그러나 정상 뇌에서 수지상세포의 분포 상태 뿐만 아니라 연령에 따른 세포수 및 형태의 변화에 대해서도 보고된 바 없는 실정이다. 그러므로 본 연구자는 연령에 따른 세포수 및 형태학적인 변화를 구명할 목적으로 이 연구를 시도하였다. 방법: 생후 1개월, 12개월, 및 24개월 된 흰쥐의 뇌를 적출하여 냉동 연속조직절편을 제작한 다음 면역조직화학적 염색을 시행한 뒤 MHC Class II 양성 면역반응성 수지상세포를 관찰하고 계수하였다. 결과: 1)MHC Class II 양성 면역반응 수지상세포는 맥락막총과 백색질에서 관찰되었다. 2)나이가 많아짐에 따라 수지상세포는 증가되었다. 3)연령이 증가함에 따라 수지상세포는 세포질돌기의 분지양상은 더욱 복잡해졌고, 일부 세포들은 군집을 이루었다. 결론: 연령이 증가함에 따라 맥락막총 및 백색질에 분포하는 수지상 세포들은 수적으로 증가할 뿐만 아니라 세포질돌기도 복잡해져 면역반응성을 증대시키는 결과를 초래할 것으로 추측된다. PURPOSE: Dendritic cells are antigen presenting cells(APC) that express class II major histocompatibility complex gene products on their surface. Recently, it was proved that dendritic cells activate antitumor immunity for intracranial germ cell tumor. The aim of the present study is to investigate the age-related changes of MHC class II-immunoreactive dendritic cells in the rat brain. METHODS: Male rats(Sprague-Dawley) were sacrificed at 1 month, 12 months and 24 months after birth. Brains were removed and sliced in rat brain matrix. Brain slices were cryosectioned coronally at interaural 5.70-6.70 mm. Brain tissue sections were immunohistochemically reacted with monoclonal MHC class II antibody. RESULTS: MHC class II-immunoreactive dendritic cells were observed in choroid plexuses and white matter(corpus callosum, cerebral peduncle and external capsule). The number of MHC class II-immunoreactive dendritic cells was slightly increased with age. As age increases, shapes of MHC class II-immunoreactive dendritic cells became more complex and aggregated together. CONCLUSION: As age increases, MHC class II-immunoreactive dendritic cells in choroid plexuses and white matter of the brain became not only more complex in shape, but also increased in number to improve immunity.

MHC Class II+ (HLA-DP-like) Cells in the Cow Reproductive Tract: I. Immunolocalization and Distribution of MHC Class II+ Cells in Uterus at Different Phases of the Estrous Cycle

Eren, U.,Sandikci, M.,Kum, S.,Eren, V. Asian Australasian Association of Animal Productio 2008 Animal Bioscience Vol.21 No.1

This study was undertaken to investigate the distribution of major histocompatibility complex class II positive (MHC II+) (HLA-DP-like) cells in the cow uterus (cervix, corpus and cornu uteri) and to compare these cells between the estrus and diestrus phases of the estrous cycle. Twenty-nine multiparous cows were used. Tissue samples from the middle of the cervix, the corpus and the right cornu were taken immediately after slaughter at the estrus or diestrus phase. Streptavidin-biotin peroxidase complex staining was used to detect MHC II+ cells. The number of MHC II+ cells per unit area of tissue was counted using image analysis software under a light microscope. Numerous MHC II+ cells were found in the endometrium (cervix, corpus and cornu uteri) in both estrus and diestrus. MHC II+ cells were found in the surface epithelium of the cervix uteri in diestrus, but in the corpus uteri in both estrus and diestrus and in the cornu uteri in estrus. MHC II+ cells were also found freely in the lumen of the glands and between the gland epithelia of the corpus and cornu uteri in both estrus and diestrus. There were also MHC II+ cells in the connective tissue of the myometrium and perimetrium (outside the endometrium) and around the blood vessels. Endothelial cells were frequently positive for MHC II staining. More MHC II+ cells were found in the endometrium than outside the endometrium in both estrus and diestrus (p<0.001). However, there was no difference in the numbers of positive cells between estrus and diestrus either in the endometrium or outside it. These results are the first evidence for HLA-DP-like MHC II+ cells in the bovine uterus. They indicate that antigen presentation by HLA-DP-like MHC II+ cells of the uterus is not influenced by hormonal status.

Regulation of Innate Immunity via MHC Class II-mediated Signaling; Non-classical Role of MHC Class II in Innate Immunity

Hye-Lim Park,남재환 대한미생물학회 2011 Journal of Bacteriology and Virology Vol.41 No.3

MHC class II has long been known to play a classical role in antigen presentation and to act as a signal transducer capable of inducing the adaptive immunity needed to produce pathogen specific antibodies. However, it has recently been revealed that MHC class II can also promote the activation of Toll-like receptor mediated signaling by functioning as an adapter. This means that in addition to its classical function of adaptive immunity, MHC class II also plays an intriguing role in the mechanisms that regulate innate immunity. That being the case, queries inevitably arise regarding the fact that many pathogens have tried to control the induction of MHC class II so as to escape the host immune response. Liu et al (Nat Immunol 2011;12:416-424) demonstrated that intracellular MHC class II interacted with Btk,and that this activated Btk promoted TLR signaling via Myd88 and TRIF. The results of this study provide insight regarding the possibility of a novel role for MHC class II, which was heretofore regarded solely as a classical molecule involved in adaptive immune responses, as a regulator of innate immune responses.

Cross-linking of MHC class II molecules interferes with phorbol 12,13-dibutyrate-induced differentiation of resting B cells by inhibiting Rac-associated ROS-dependent ERK/p38 MAP kinase pathways leading to NF-κB activation

Yang, H.Y.,Kim, J.,Chung, G.H.,Lee, J.C.,Jang, Y.S. Pergamon Press 2007 Molecular immunology Vol.44 No.7

In addition to their essential role in antigen presentation, major histocompatibility complex (MHC) class II molecules have been described as the receptor associated with signal transduction regulating B-cell function. In previous experiments, we found that cross-linking of MHC class II molecules with corresponding anti-MHC class II antibodies inhibited NF-κB-activated signaling pathways associated with the proliferation and differentiation of the LPS-stimulated primary and resting B-cell line, 38B9. We also found that exposure to the anti-MHC class II antibody reduced the production of ROS, which function as secondary signal transducers, in the phorbol 12,13-dibutyrate (PDBU)-treated (but not in the LPS-treated) resting B-cell line. In this study, we investigated the molecular mechanisms in the ROS-associated signaling pathway leading to PDBU-induced NF-κB activation that results in B-cell differentiation and speculated that the signaling pathway was inhibited by exposure to the anti-MHC class II antibody. We also found that this inhibition was mediated through down-regulation of the activated Rac/ROS-associated ERK/p38 MAPK signaling pathway in PDBU-treated 38B9 cells. Collectively, these findings suggest that ROS-associated molecules are involved in MHC class II-associated negative signal transduction in resting B cells.

한국인 IgA 신병증 환아에서 MHC Class II유전자형과 예후와의 관계 분석

김병길,육진원,김지홍,장윤수,신전수,최인홍,Kim Pyung Kil,Yook Jinwon,Kim Ji Hong,Jang Yoon Soo,Shin Jeon-Soo,Choi In-Hong 대한소아신장학회 2000 Childhood kidney diseases Vol.4 No.1

Purpose: Our study was designed to investigate the association of MHC Class II (DR, DQ) allele with IgA nephropathy and its significance as a prognostic factor for progression to ESRD Material and Methods: 69 children with IgA nephropathy with normal renal function(serum creatinine $\leq$ 1.5mg/dL) was classified as group A and 70 patients who received renal transplantation due to IgA nephropathy were selected as group B. The HLA-DQB1 and HLA-DRB1 alleles were studied by polymerase chain reaction using sequence specific primers. We have compared the difference in alleles between these two groups and with normal control and also examined any possible effect of the MHC class II genes on the histopathological severity and prognosis of IgAN. Results: Mean age was $8.8{\pm}2.9$ years in group A and $35.0{\pm}15.5$ years in group B. Male to female ratio was 2.8:1 in group A and 2.5:1 in group B. There was a significantly higher frequency of HLA-$DQB1^*03\;and\;DQB1^*05$ in Group B. The frequency of HLA-$DQB1^*0302\;and\;^*05031$ allele had increasing tendency in Group B(P<0.05). HLA-$DRB1^*03\;and\;^*05$ were more common in Group B(P<0.05). HLA-$DRB1^*04$ allele was the most common DR alleles in both group, but there was no statistical significance. There were no significant correlation with MHC class 13 genes on the hjstopathological severity in Group A. Conclusion: In conclusion, $HLA-DQB1^*0302\;and\;HLA-DQB1^*05031 $ allele seemed to be more common in transplanted patients compared to group with normal renal function suggesting that this allele is associated with poor prognosis in IgAN. However larger studies and follow up are required to confirm this due to uncharacterized heterogeneity in etiopathogenesis of IgA nephropathy and possibly one or more than one gene may exert influence in determining susceptibility to the diseases. 목 적 : IgA 신병증은 혈뇨와 단백뇨를 보이는 사구체 질환으로 세계적으로 가장 빈도가 높은 질환중의 하나 이며 우리 나라를 포함한 아시아 지역에서도 높은 발생율을 보이고 있으나 아직 정확한 발생기전이나 원인은 불분명한 상태이다. IgA 신병증은 발병 10년 후 $20-30\%$가 말기 신부전증으로 진행됨이 보고되고 있으나 신부전으로 진행속도는 환자에 따라 매우 다양하기 때문에 특이적인 조직적합항원을 찾아냄으로서 치료 및 예후 결정에 도움을 주기 위하여 본 연구를 시행하였다. 대상 및 방법 : 세브란스 병원에 입원하여 IgA 신병증으로 진단 받은 환자를 대상으로 정상 신기능을 유지하고 있었던 소아환아 69명(Group A)과 이미 신부전으로 진행하여 신이식을 시행 받은 70명(Group B)을 포함한 신기능 저하군으로 분류하여 HLA대립유전자의 결정은 SSOP (sequence specific oligonucleotide probe)법으로 분석하여 HLA-class II(DR, DQ)대립유전자의 발현빈도와 IgA 신병증의 예후와의 관계를 분석하였다. 결 과 : 대상 환자의 진단 당시의 평균나이는 A군은 $8.8{\pm}2.9$세, B군은 $35.0{\pm}15.5$세였고, 남녀비는 각각 2.8:1과 2.5:1이었다. HLA-DQB1 유전자중 139명중 $47.5\%$로 $03^{**}$의 발현빈도가 가장 증가되어 있었고 $06^{**}(32.4\%),\;04^{**}(28.7\%),\;05^{**}(20.1\%),\;02^{**}(8.6\%)$순이 었다. DQ7의 HLA-DQB1*0301 이 전체 환자의 20.1$\%$(28/139)로 가장 흔한 대립유전자였으나 두군간에 유의한 차이는 없었다. 대립유전자중 HㄴA-$DQBI^*03^{**}과\;DQB1^*05^{**}$가 이미 말기신부전으로 진행된 Group B에서 유의하게 증가되어 있었으며(P<0.05), $03^{**}$ 아형중 $DQB1^{*}0302와\;05^{**}중\;DQB1^{*}05031$이 신기능이 정상인 A군에 비해 유의하게 증가되어 있었다(P<0.05). DR 유전자형의 low-frequency type상 HLA-$DRB1^*03과\;HLA-DRB1^*15$가 Group B에서 유의 있게 증가되어 있었으나, high-frequency type상에서는 양군 사이에 유의한 차이가 없었다. A군의 경우 신조직 검사의 소견에 따라 4등급으로 분류하여 대립유전자의 발현빈도를 분석하였으나 의미 있는 관계가 없었다. 곁 론 : IgA신병증의 예후를 예측하기 위한 여러 조사에서 발병 초기의 심한 단백뇨, 고혈압, 조직 병리학상의 심한 변화 등이 있을 경우 예후가 나쁘다고 하였으며 이런 위험 인자외에 유전적 요인에 대해 알아보고자 하였다. 본 연구에서 신부전으로 진행하여 신대체요법을 받은 IgA신병증환자군에서 HLA-$DQB1^*0302와\;^*05031$ 대립유전자의 발현빈도가 유의하게 증가되어 있어 이 결과를 바탕으로 치료후의 경과 및 예후를 진단초기에 예측하여 환자의 관리에 적용할수 있는 중요한 자료로 이용될 수 있을 것으로 사료된다.

Sulforaphane Enhances MHC Class II-Restricted Presentation of Exogenous Antigens

( Chong Kil Lee ),( Yoon Hee Park ),( Nam Joo Ha ),( Kyung Jae Kim ),( Kyung Hae Cho ),( Seul Mee Shin ),( Ki Sung Jung ),( Young Wook Ko ) 한국응용약물학회 2011 Biomolecules & Therapeutics(구 응용약물학회지) Vol.19 No.1

Sulforaphane is an isothiocyanate found in cruciferous vegetables that has been reported to be an effective cancer preventive agent inducing growth arrest and/or cell death in cancer cells of various organs. This paper reports that sulforaphane exerts immunomodulatory activity on the MHC-restricted antigen presenting function. Sulforaphane efficiently increased the class II-restricted presentation of an exogenous antigen, ovalbumin (OVA), in both dendritic cells (DCs) and peritoneal macrophages in vitro. The class II-restricted OVA presentation-enhancing activity of sulforaphane was also confirmed using mice that had been injected with sulforaphane followed by soluble OVA. On the other hand, sulforaphane did not affect the class I-restricted presentation of exogenous OVA at concentrations that increase the class II-restricted antigen presentation. At a high concentration (20 uM), sulforaphane inhibited the class I-restricted presentation of exogenous OVA. Sulforaphane did not affect the phagocytic activity of the DCs, and the cell surface expression of total H-2Kb, B7-1, B7-2 and CD54 molecules, even though it increased the expression of I-Ab molecules to a barely discernable level. These results show that sulforaphane increases the class II-restricted antigen presenting function preferentially, and might provide a novel insight into the mechanisms of the anti-cancer effects of sulforaphane

Rac/ROS-related protein kinase C and phosphatidylinositol-3-kinase signaling are involved in a negative regulating cascade in B cell activation by antibody-mediated cross-linking of MHC class II molecules

Yang, H.Y.,Kim, J.,Lee, K.Y.,Jang, Y.S. Pergamon Press 2010 Molecular immunology Vol.47 No.4

In addition to their essential role in antigen presentation, MHC class II molecules have been widely described as receptors associated with signal transduction involved in regulating B cell function. However, their precise function and mechanism in signal transduction are not yet fully elucidated. Our previous studies demonstrated that cross-linking of MHC class II molecules led to the inhibition of resting B cell activation in which various signal molecules were involved. Especially, Rac-associated ROS-dependent MAP kinases, including ERK½ and p38, are involved in MHC class II-associated negative signal transduction in the phorbol 12, 13-dibutyrate (PDBU)-treated, but not LPS-treated, resting B cell line, 38B9. In this study, we further illustrated that PKC regulates downstream signal molecules, including MAP kinases and NF-κB in PDBU-stimulated resting B cells, together with Rac and ROS. In addition, we found that phosphatidylinositol 3-kinase (PI3K)-dependent activation of ERK/p38 MAP kinases was associated with the signaling procedure in PDBU-induced B cell activation. Collectively, Rac/ROS-related PKC and PI3K signaling are involved in a negative regulation cascade through the cross-linking of MHC class II molecules by anti-MHC class II antibodies in resting B cells.

Introduction of the CIITA gene into tumor cells produces exosomes with enhanced anti-tumor effects

Yeong Shin Lee,김철우,Soo Hyun Kim,조정아 생화학분자생물학회 2011 Experimental and molecular medicine Vol.43 No.5

Exosomes are small membrane vesicles secreted from various types of cells. Tumor-derived exosomes contain MHC class I molecules and tumor-specific antigens,receiving attention as a potential cancer vaccine. For induction of efficient anti-tumor immunity, CD4+helper T cells are required, which recognize appropriate MHC class II-peptide complexes. In this study,we have established an MHC class II molecule-expressing B16F1 murine melanoma cell line (B16F1-CIITA) by transduction of the CIITA (Class II transactivator)gene. Exosomes from B16-CII cells (CIITAExo)contained a high amount of MHC class II as well as a tumor antigen TRP2. When loaded on dendritic cells (DCs), CIITA-Exo induced the increased expression of MHC class II molecules and CD86 than the exosomes from the parental cells (Exo). In vitro assays using co-culture of immunized splenocytes and exosome-loaded DCs demonstrated that CIITA-Exo enhanced the splenocyte proliferation and IL-2 secretion. Consistently, compared to B16-Exo, CIITA-Exo induced the increased mRNA levels of inflammatory cytokines such as TNF-α, chemokine receptor CCR7 and the production of Th1-polarizing cytokine IL-12. A tumor preventive model showed that CIITA-Exo significantly inhibited tumor growth in a dose-dependent manner. Ex vivo assays using immunized mice demonstrated that CIITA-Exo induced a higher amount of Th1-polarized immune responses such as Th1-type IgG2a antibodies and IFN-γ cytokine as well as TRP2-specific CD8+ T cells. A tumor therapeutic model delayed effects of tumor growth by CIITA-Exo. These findings indicate that CIITA-Exo are more efficient as compared to parental Exo to induce anti-tumor immune responses, suggesting a potential role of MHC class II-containing tumor exosomes as an efficient cancer vaccine.

Introduction of the $CIITA$ gene into tumor cells produces exosomes with enhanced anti-tumor effects

Lee, Yeong-Shin,Kim, Soo-Hyun,Cho, Jung-Ah,Kim, Chul-Woo Korean Society for Biochemistry and Molecular Bion 2011 Experimental and molecular medicine Vol.43 No.5

Exosomes are small membrane vesicles secreted from various types of cells. Tumor-derived exosomes contain MHC class I molecules and tumor-specific antigens, receiving attention as a potential cancer vaccine. For induction of efficient anti-tumor immunity, CD4+ helper T cells are required, which recognize appropriate MHC class II-peptide complexes. In this study, we have established an MHC class II molecule-expressing B16F1 murine melanoma cell line (B16F1-CIITA) by transduction of the $CIITA$ (Class II transactivator) gene. Exosomes from B16-CII cells (CIITA-Exo) contained a high amount of MHC class II as well as a tumor antigen TRP2. When loaded on dendritic cells (DCs), CIITA-Exo induced the increased expression of MHC class II molecules and CD86 than the exosomes from the parental cells(Exo). $In$ $vitro$ assays using co-culture of immunized splenocytes and exosome-loaded DCs demonstrated that CIITA-Exo enhanced the splenocyte proliferation and IL-2 secretion. Consistently, compared to B16-Exo, CIITA-Exo induced the increased mRNA levels of inflammatory cytokines such as TNF-${\alpha}$, chemokine receptor CCR7 and the production of Th1-polarizing cytokine IL-12. A tumor preventive model showed that CIITA-Exo significantly inhibited tumor growth in a dose-dependent manner. $Ex$ $vivo$ assays using immunized mice demonstrated that CIITA-Exo induced a higher amount of Th1-polarized immune responses such as Th1-type IgG2a antibodies and IFN-${\gamma}$ cytokine as well as TRP2-specific CD8+ T cells. A tumor therapeutic model delayed effects of tumor growth by CIITA-Exo. These findings indicate that CIITA-Exo are more efficient as compared to parental Exo to induce anti-tumor immune responses, suggesting a potential role of MHC class II-containing tumor exosomes as an efficient cancer vaccine.