Molecular characterization and clinical presentation of HKαα and anti‐HKαα alleles in southern Chinese subjects

The HKαα allele is a rearrangement occurring in the α‐globin gene cluster containing both the ‐α^3.7 and ααα^anti4.2 unequal crossover junctions. The anti‐HKαα allele is the reciprocal product containing both the ‐α^4.2 and ααα^anti3.7 unequal crossover junctions, which had been predicted but had not been detected previously. The phenotypic feature and population frequency of these two unusual alleles were not described. We report the identification of nine individuals carrying the HKαα allele and two individuals carrying the anti‐HKαα allele in southern China and describe their phenotype and haplotype data. The molecular structures of HKαα allele and anti‐HKαα allele were confirmed by two‐round nested polymerase chain reaction assay. The mechanism of origin of both alleles is related to probably simultaneous double crossover. Heterozygotes of HKαα or anti‐HKαα allele show a normal hematological phenotype. Finally, we report the carrier rates of these both alleles in the Guangxi Zhuang Autonomous Region of southern China, namely, ∼0.07% for the HKαα allele and ∼0.02% for the anti‐HKαα allele.     

Cytotoxic protein expression in natural killer cell lymphomas and in αβ and γδ peripheral T-cell lymphomas

Lymphomas with T-cell phenotype represent a heterogeneous group of diseases differing in histopathology, tumour site, and cell origin. They include peripheral T-cell lymphomas (PTCLs) derived from αβ cells, but also some recently recognized entities such as γδ hepatosplenic lymphomas and natural killer (NK) cell lymphomas. Only a few studies have investigated the possibility that at least some PTCLs could be derived from lymphocytes with cytotoxic potential. In order to investigate this possibility, 60 cases of PTCL, including 27 cases expressing the αβ T-cell receptor (TCRαβ), 15 TCRγδ cases and 18 cases expressing neither TCR (TCR silent), as well as 14 cases of NK-cell lymphomas, were studied by immunohistochemistry for the expression of TIA-1, perforin, and granzyme B proteins. Expression of TIA-1 is characteristic of cytotoxic cells regardless of their activation status, whereas expression of perforin and granzymes is highly increased in activated cytotoxic cells and correlates with the induction of cytolytic activity. All NK-cell lymphomas (11 sinonasal, three systemic cases) expressed TIA-1, perforin, and granzyme B in most tumour cells. All γδ PTCLs (15 cases) expressed TIA-1 protein in most tumour cells, with a different cytotoxic antigen profile in hepatosplenic γδ PTCL (TIA-1+, perforin−, granzyme B−) and in non-hepatosplenic γδ PTCLs (three nasal, one skin, one lung), the latter expressing the three cytotoxic proteins. Of the 45 cases of αβ and TCR silent PTCL, 15 (33 per cent) were considered to be derived from cytotoxic lymphocytes with expression of at least one cytotoxic protein (TIA-1, 15/45; perforin, 10/41; granzyme B, 14/38) in tumour cells. This cytotoxic protein expression appeared to be related to the site of localization, since 7/13 (54 per cent) extranodal and only 8/32 (25 per cent) nodal αβ and TCR silent PTCLs expressed TIA-1, and to histology, since this pattern was observed in a proportion of anaplastic (6/8, 75 per cent) and pleomorphic (8/17, 47 per cent) lymphomas, but not in AILD-type NHL (0/16). Taken together, our data suggest that NK-cell lymphomas and non-hepatosplenic γδ PTCLs represent tumours of activated cytotoxic NK cells and γδ T cells, respectively; that hepatosplenic γδ PTCLs represent tumours of non-activated cytotoxic γδ T cells; and that a small proportion of αβ and TCR silent PTCLs, mostly extranodal cases, or nodal anaplastic lymphomas, represent tumours of cytotoxic T cells. © 1997 John Wiley & Sons, Ltd.     

Establishment and characterization of αs1-casein–specific T-cell lines from patients allergic to cow’s milk: Unexpected higher frequency of CD8 T-cell lines

To study cow’s milk allergy at the cellular level, we assessed the reactivity of peripheral blood mononuclear cells from patients allergic to cow’s milk to α_s1-casein, which is one of the major allergens in cow’s milk. Proliferation of the cells to α_s1-casein activation showed a rather weak response. Therefore to understand T-cell reactivity to α_s1-casein in more detail, we prepared α_s1-casein–specific T-cell lines from patients allergic to cow’s milk and established 26 T-cell lines. These T-cell lines could be classified into three groups by analyzing their surface marker expression: those containing predominantly CD4⁺CD8^- T cells, those containing both CD4⁺CD8^- and CD4^-CD8⁺ T cells, and those containing predominantly CD4^-CD8⁺ T cells. The CD8⁺ T cells were obtained at an unexpectedly higher frequency from the patients. These T-cell lines produced interferon-γ and IL-4. These results suggest that CD8⁺ T cells specific for α_s1-casein and CD4⁺ T cells were primed by the stimulation with α_s1-casein in patients allergic to milk and that both T cells may play a key role in the onset, progression of, or recovery from cow’s milk allergy. (J ALLERGY CLIN IMMUNOL 1996;97:1342-9.)     

Recognition of HLA-A3 and HLA-A11 by KIR3DL2 is peptide-specific

The recognition of MHC class I molecules by killer cell immunoglobulin-like receptors (KIR) is central to the control of NK cell function and can also modulate the CTL activation threshold. Among KIR receptors, KIR3DL2 is thought to interact with HLA-A3 and -A11, although direct evidence has been lacking. In this study, we show that HLA-A3 and -A11 tetramers specifically bind to KIR3DL2*001 transfectants and that this recognition is peptide-specific. Single amino acid substitutions in the nonamer peptide underline a critical role for residue 8 in recognition of KIR3DL2. However, the role of this interaction in vivo still remains to be established.     

The Suppressive Function of Human CD8+ iTregs is Inhibited by IL‐1β and TNFα

CD8⁺ Tregs display an immunoregulatory activity and may play an essential role in the immunopathology of several diseases. Therefore, their therapeutic potential is exquisite and further studies on their differentiation and function are essential. The aim of this study was to evaluate the role of the innate immune system in CD8⁺ iTreg differentiation and function. Naive human CD8⁺CD25^?CD45RA⁺ T cells were cultured in Treg‐inducing conditions with or without IL‐1β, TNFα or monocyte‐derived dendritic cells (DCs). The differentiation of CD8⁺CD127^?CD25^hiFoxP3^hi‐induced Tregs (CD8⁺ iTregs) is dependent on TGF‐β1 and IL‐2, which had synergistic effect upon their differentiation. CD8⁺ iTregs were also induced in a coculture with allogeneic mature DCs (mDCs). The CD8⁺ iTregs suppressive function was confirmed, which was diminished in the presence of IL‐1β and TNFα. The IL‐1β‐prevented suppressive function was associated with reduced secretion of IL‐10 and IFNγ, whereas the presence of TNFα did not affect their secretion. Furthermore, the presence of TNFα reduced IL‐10 and TGF‐β1 secretion by CD8⁺ iTregs, whereas only IL‐10 secretion was decreased by IL‐1β. Together, these results suggest that IL‐1β and TNFα prevent IL‐2‐ and TGF‐β1‐driven CD8⁺ iTregs suppressive function in human T cells. Such pro‐inflammatory innate immune response possibly mediates its negative tolerogenic effect through reduced IFNγ‐, IL‐10‐ and TGF‐β1‐driven mechanism.     

Delayed-type hypersensitivity reaction to paraphenylenediamine is mediated by 2 different pathways of antigen recognition by specific αβ human T-cell clones

Background: Allergic contact dermatitis to paraphenylenediamine (PPD) is a frequent cause of morbidity and occupational disability. Objective: The aim of the study was to characterize T-cell responses to PPD and Bandrowski's base (BB), an autoxidation product of PPD, by using polyclonal and monoclonal T-lymphocyte cultures. Methods: PPD- and BB-driven proliferation of PBMCs and T-cell clones (TCCs) was assessed by means of tritiated thymidine incorporation. Surface markers were studied by means of flow cytometry, and cytokine generation was assessed with an ELISA. Results: TCCs, with one exception, were CD4⁺/CD45RO⁺, and T-cell receptors were αβ⁺. Three of 6 TCCs expressed Vβ 16. TCC stimulation was HLA-DP restricted, and TCCs secreted IL-4, IL-5, and marginal levels of IFN-γ. TCCs reacted to both PPD and BB. Presentation of BB to TCCs was dependent on viable antigen-presenting cells (APCs) pulsed for 4 hours, and fixed APCs failed to stimulate TCCs. Moreover, polyclonal responses to BB were enhanced by metabolically active enzymes, such as cytochrome P450 enzymes. BB has to be metabolized and processed. In contrast, fixation of APCs did not impair their ability to present PPD to TCC, whereas pulsing of APCs with PPD failed to stimulate TCCs. Thus PPD had to be present during the process, and polyclonal stimulation was not enhanced by cytochromes. Conclusion: These results suggest that PPD itself can be recognized by T cells through a processing-independent pathway, whereas its autoxidation product, BB, required processing and possibly metabolism to stimulate the same TCC. Our data demonstrate that 2 distinct pathways of antigen presentation to activate specific TCCs are involved in the immune response to PPD. (J Allergy Clin Immunol 2002;109:1005-11.)     

AMBRA1, a novel α‐synuclein‐binding protein,is implicated in the pathogenesis of multiple system atrophy

The accumulation of abnormal α‐synuclein is the major histopathological feature of Lewy body disease and multiple system atrophy (MSA), which are referred to as synucleinopathies. Cytoplasmic degradation systems, such as the autophagy‐lysosome and proteasome pathways, are involved in their pathogenesis. Autophagy is tightly regulated by several upstream proteins including UNC‐51‐like kinase 1/2, beclin1, vacuolar protein sorting‐associated protein 34 and autophagy/beclin1 regulator 1 (AMBRA1). Recently, we revealed that both cortical and brainstem‐type Lewy bodies were immunopositive for several upstream proteins of autophagy. Therefore, we conducted the present study to elucidate the role of upstream proteins of autophagy in the pathogenesis of MSA. Pathological and biochemical analyses using human brain samples revealed that AMBRA1 is a component of the pathological hallmarks of MSA and upstream proteins of autophagy are impaired in the MSA brain. In vitro and in vivo analyses revealed a ninefold stronger affinity of AMBRA1 with α‐synuclein phosphorylated at serine 129 compared with non‐phosphorylated α‐synuclein. Furthermore, a weak but significant correlation between AMBRA1 overexpression and reduction of abnormal α‐synuclein was observed. Silencing AMBRA1 function caused aggregates of α‐synuclein in the cytoplasm of mouse primary cultured neurons, which was simulated by the treatment of Bafilomycin, an autophagy inhibitor. Our results demonstrated for the first time that AMBRA1 is a novel hub binding protein of α‐synuclein and plays a central role in the pathogenesis of MSA through the degradative dynamics of α‐synuclein. These results raise the possibility that molecular modulation targeting AMBRA1 can be a promising candidate for the treatment of synucleinopathies.     

An immunohistochemical examination of the expression of E-cadherin, α- and β/γ-catenins,and α2- and β1-integrins in invasive breast cancer

This study examines the expression of the cell–cell adhesion molecules E-cadherin and its associated proteins, the catenins and the matrix–cell adhesion molecules β1- and α2-integrins, in primary invasive breast carcinoma. Expression was assessed immunohistochemically on frozen sections by semi-quantitative scoring of the intensity and proportion of immunoreactivity in 55 cases. Associations with each other and with other histological and prognostic features and survival were sought. There was a significant association between loss of E-cadherin expression and loss of α- and β/γ-catenin immunostaining. In 20 per cent of cases, membranous immunoreactivity with E-cadherin antibody was absent. Absent cytoplasmic expression of α- and β/γ-catenins was seen in 24 and 22 per cent of breast cancers, respectively. The intensity of reactivity with E-cadherin showed a significant association with histological grade (p = 0·002) and tumour type (p < 0·001). Lobular carcinomas frequently showed loss of expression of E-cadherin, as reported elsewhere; loss of catenin expression was also found in these tumours. α-Catenin intensity also showed a relationship with grade (p = 0·008) and with oestrogen receptor (ER) status (p = 0·006). β/γ-Catenin expression was not associated with other known prognostic factors. Forty-nine per cent and 42 per cent of cases showed no membrane immunostaining with β1- and α2-integrin, respectively, and co-ordinated loss of β1- and α2-integrin expression was found. Both β1- and α2-integrin expression were associated with histological grade (p = 0·003 and p = 0·031, respectively) and β1 immunoreactivity with tumour type (p = 0·010). None of the variables examined showed a statistically significant association with tumour size or lymph node stage, or with overall survival, although a trend was seen (p = 0·087) towards poorer survival of patients with tumours with absent or weak expression of β1-integrin. The expression of these markers is of biological interest, but appears to be of little additional use in predicting clinical behaviour. Copyright © 1999 John Wiley & Sons, Ltd.     

An active CD8α/pMHCI interaction is required for CD8 single positive thymocyte differentiation

Recognition of viral antigenic peptides bound to major histocompatibility complex class I molecules (MHCI) by TCR is critical for initiating the responses of CD8⁺ T cells that ultimately lead to elimination of virus‐infected cells. This antigen recognition is enhanced by the CD8 coreceptor through its interaction with the peptide‐MHCI complexes (pMHCI). Mouse CD8αβ can form two different complexes with pMHCI via either the CD8α‐ or CD8β‐dominated interaction. To understand the functional significance of these complexes in vivo, we generated Tg mice carrying a variant CD8αβ (CD8α^m3β) capable of forming only the CD8β‐dominated CD8αβ/pMHCI complex. These mice show sub‐optimal thymic differentiation with reduced populations of CD8⁺ single‐positive thymocytes. Tg CD8⁺ T cells exhibit a compromised developmental capacity when competing with CD8⁺ T cells from B6 mice in mixed bone marrow chimera experiments. However, once these CD8⁺ T cells have emigrated to the peripheral lymphoid organs, they exhibit normal effector function against viral infection. Our observations indicate that, in addition to the CD8 activity conferred by CD8β‐dominated CD8αβ/pMHCI complexes, full thymocyte differentiation requires additional coreceptor activities conferred by CD8αα and/or CD8αβ with CD8α‐dominated CD8/pMHCI complexes.     

Migration of encephalitogenic CD8 T cells into the central nervous system is dependent on the α4β1‐integrin

Although CD8 T cells are key players in neuroinflammation, little is known about their trafficking cues into the central nervous system (CNS). We used a murine model of CNS autoimmunity to define the molecules involved in cytotoxic CD8 T‐cell migration into the CNS. Using a panel of mAbs, we here show that the α4β1‐integrin is essential for CD8 T‐cell interaction with CNS endothelium. We also investigated which α4β1‐integrin ligands expressed by endothelial cells are implicated. The blockade of VCAM‐1 did not protect against autoimmune encephalomyelitis, and only partly decreased the CD8⁺ T‐cell infiltration into the CNS. In addition, inhibition of junctional adhesion molecule‐B expressed by CNS endothelial cells also decreases CD8 T‐cell infiltration. CD8 T cells may use additional and possibly unidentified adhesion molecules to gain access to the CNS.     

中国人类风湿关节炎与PAD14功能基因多态性及部分HLA-DRB1等位基因相关性研究

目的 分析类风湿关节炎(rheumatoid arthritis,RA)中4型肽精氨酸转亚胺基酶(peptidylarginine deiminase IV,PAD14)功能基因多态性,探讨PAD14基因多态性与RA易感性的关系,以及编码与RA易感性相关HLA共同表位(shared epitope,SE)的HLA-DRB1等位基因与PAD14基因多态性的相关性.方法 采用逆转录合成cDNA、DNA测序和T载体克隆方法 分析67例RA患者、81名正常人PAD14基因外显子4个单核苷酸多态性(single nucleotide polymorphisms,SNPs),包括PADH_89*A/G,PADl4 90*C/T,PAD1492*C/G,PAD14 104*C/T;采用PCR-序列特异性引物方法 分析HLA-DRB1.*-01、*04、* 10基因型.结果 RA患者PAD14 89、90、104位基因多态性分布与正常对照组比差异有统计学意义,携带PAD14少见等位基因者对RA的危险性较携带常见等位基因者显著增加;分析编码SE等位基因与PAD14 SNPs的相关性发现,SE+/PAD14_89G-携带者较SE-/PAD14_89G-携带者发生RA的危险性高4.7倍(OR=4.7,95%CI:1.6～13.4,P=0.003),携带SE+/PAD14 89G+者高5.6倍(OR=5.6,95%CI:2.0～15.7,P=0.003).在PAD14 90、92、104位均出现相似的情况.结论 PAD14功能基因多态性与中国人RA的易感性相关,编码SE的HLA-DRB1等位基因仍然是RA的重要遗传标记,而且HLA-DRB1等位基因与PAD14的少见等位基因间可能存在一定的协同作用.     

DL4‐mediated Notch signaling is required for the development of fetal αβ and γδ T cells

T‐cell development depends upon interactions between thymocytes and thymic epithelial cells (TECs). The engagement of delta‐like 4 (DL4) on TECs by Notch1 expressed by blood‐borne BM‐derived precursors is essential for T‐cell commitment in the adult thymus. In contrast to the adult, the earliest T‐cell progenitors in the embryo originate in the fetal liver and migrate to the nonvascularized fetal thymus via chemokine signals. Within the fetal thymus, some T‐cell precursors undergo programmed TCRγ and TCRδ rearrangement and selection, giving rise to unique γδ T cells. Despite these fundamental differences between fetal and adult T‐cell lymphopoiesis, we show here that DL4‐mediated Notch signaling is essential for the development of both αβ and γδ T‐cell lineages in the embryo. Deletion of the DL4 gene in fetal TECs results in an early block in αβ T‐cell development and a dramatic reduction of all γδ T‐cell subsets in the fetal thymus. In contrast to the adult, no dramatic deviation of T‐cell precursors to alternative fates was observed in the fetal thymus in the absence of Notch signaling. Taken together, our data reveal a common requirement for DL4‐mediated Notch signaling in fetal and adult thymopoiesis.     

High frequency of CD8αα homodimer-bearing T cells in human fetal intestine

Immunohistochemistry on frozen sections was used to identify CD8αα cells and CD8αβ cells in human intestine. As observed previously, CD8αβ cells predominate (>95%) in tonsil and post-natal intestine. However in human fetal intestine (16–24 weeks gestation), almost half the CD8⁺ cells in the lamina propria are CD8αα, and many CD8αα cells can be identified in the epithelium. In contrast, in the T cell zones of the Peyer's patches, CD8αβ cells are dominant. The CD8αα cells are virtually all αβ T cell receptor positive. By analogy with the murine system, these CD8αα cells in the fetal gut may be directly derived from the marrow, undergoing thymus-independent differentiation in the gut mucosa.     

A T-cell clone recognizing an MLC stimulating epitope located on the DRw11β1 chain

An alloreactive proliferative T-cell clone, 6065 WS, was obtained in an intrafamilial cell combination where the stimulator was a homozygous DRw11, DRw52, DQw3 son and the responder his haploidentical mother. Proliferation assays on eight local DRw11 families, 75 homozygous B-cell lines (Tenth Histocompatibility Workshop panel), and blocking assays with monoclonal antibodies showed that clone 6065 WS recognizes an epitope on the DRw11β1 chain. Comparison of the reactivity of clone 6065 WS with cells expressing the three known DRw11β1 amino acid sequences identified two unique amino acids at positions 71 and 86 which contribute to determining the specific recognition by the T-cell clone 6065 WS. Our data suggest that one or both of these amino acids can either be directly involved in the recognition by the T-cell receptor or responsible for critical conformation of the determinants on the DR molecule. Alternatively, they could affect recognition of a self peptide bound to the major histocompatibility complex class II molecule.     

The peptide binding motif of the disease associated HLA-DQ (α 1* 0501, β 1* 0201) molecule

To identify the binding motifs of peptides which bind to the celiac disease and insulin-dependent-diabetes-mellitus (IDDM)-associated DQ2 molecule, peptides were eluted from affinity-purified DQ2 molecules. The eluted peptides were separated by reverse-phase HPLC. Prominent peptide peaks and the remaining pool of peptides were sequenced by Edman degradation. Truncated variants of eight different peptides with a length of 9–19 amino acids were identified; among them class II-associated invariant chain peptides (CLIP) and peptides that stem from HLA class I α, HLA-DQα1*0501, Ig and CD20 molecules. Data from the pool sequencing and the biochemical binding analyses of synthetic variants of an eluted high-affinity ligand (HLA class I α 46–60), indicate that the side chains of amino acid residues at relative position P1 (bulky hydrophobic), P4 (negatively charged or aliphatic), P6 (Pro or negatively charged), P7 (negatively charged) and P9 (bulky hydrophobic) are important for binding of peptides to DQ2. Computer modeling of the DQ2 with variants of the high-affinity ligand in the groove suggests that peptides bind to DQ2 through the primary anchors P1, P7 and P9 and making additional advantageous interactions using the P4 and P6 positions.     

Expression of an avian CD6 candidate is restricted to αβ T cells,splenic CD8+ γδ T cells and embryonic natural killer cells

A candidate avian CD6 homolog is identified by the S3 monoclonal antibody. The S3 antigen exists in a phosphorylated glycoprotein form of 130 kDa and a nonphosphorylated form of 110 kDa. Removal of phosphate groups and N-linked carbohydrates indicates a 78-kDa protein core. During thymocyte differentiation, the γδ T cells do not express S3, whereas mature CD4⁺ and CD8⁺ cells of αβ lineage acquire S3 antigen. All αβ T cells in the blood and spleen express the S3 antigen at relatively high levels. In contrast, only the CD8⁺ sub-population of γδ T cells in the spleen expresses the antigen and neither αβ nor γδ T cells in the intestinal epithelium express the S3 antigen. The S3 antigen is also found on embryonic splenocytes with a phenotypic profile characteristic of avian natural killer cells. The biochemical characteristics and this cellular expression pattern imply that the S3 antigen is the chicken CD6 homolog.     

Five types of lymphocytes (lg− θ−, lg− θ+ weak,lg− θ+strong,lg+ θ− and lg+ θ+) characterized by double immunofluorescence and electrophoretic mobility Organ distribution in normal and nude mice

The simultaneous detection of Ig and θ on the surface of mouse lymphocytes permits the detection of four cell types (Ig^?θ^?, Ig^?θ⁺, Ig⁺θ^?, and Ig⁺θ⁺) which also have distinct electrophoretic profiles. All types are present in variable proportions in all lymphoid organs studied. Results obtained in congenitally athymic nude mice and in T-deprived mice define a new type of lymphocyte, the Ig^?θ^+weak. This cell is non-recirculating, Ig^?, with a low density of θ and a slow electrophoretic mobility. It is a candidate for a T-committed prethymic cell.     

Role of the thymus in the generation of skin-homing αβ and γδ virgin T cells

Current models of lymphocyte traffic suggest that homing specificities of T cells to tissues such as skin are generated outside the thymus as a result of activation of naive T cells by antigen in lymph nodes. Virgin T cells are thought to home to high endothelial venules in lymph nodes, but are thought to be unable to home to extra-lymphoid tissues such as skin. We used the technique of in situ labeling of the thymus with fluorescein isothiocyanate to examine the homing specificities of authentically naive T cells in vivo, immediately after their export from the thymus. We report that homing specificities for skin as well as lymph node are imprinted on T cells inside the thymus, independent of antigen. We also show that both αβ and γδ emigrant T cells exhibit homing patterns to skin and lymph nodes which are identical to those of mature T cells. Our findings demonstrate a key role for the thymus in the induction of skin-homing specificities on T cells indicating that skin-homing specificities of T cells are not generated solely outside the thymus as a result of the activation of virgin T cells by antigen. The migration of thymic emigrants to extra-lymphoid tissues within a few hours of leaving the thymus may have implications for mechanisms of peripheral self-tolerance. This pathway provides an opportunity for direct virgin T cell interactions with self components only expressed in the periphery at a time when emigrants may be more susceptible to tolerance induction than mature circulating T cells.     

The γ → α partial transformation in nylon 12 by drawing

Partial development of the α form crystals in γ nylon 12 has been found to take place by drawing near the melting point. The confirmation of the α form has been made by X-ray diffraction, infrared absorption, and differential scanning calorimetry. The amount of the α form varies depending upon the temperature of drawing and draw ratio, whereas it is almost independent of the rate of drawing. The minimum draw ratio necessary to yield the α form increases as the temperature of drawing decreases. The crystallinity, determined from the density, also increases with the increase in the temperature of drawing and draw ratio, while it decreases slightly with the increase in the rate of drawing. The development of the α form is ascribable to the transformation from the γ form rather than the crystallization from the amorphous region. The total figure of the polymorphism in nylon 12 is proposed.