Association of rheumatoid arthritis and primary osteoarthritis with changes in the glycosylation pattern of total serum IgG

Rheumatoid arthritis (RA) is a widely prevalent (1-3%) chronic systemic disease thought to have an autoimmune component; both humoral and cellular mechanisms have been implicated. Primary osteoarthritis (OA) is considered to be distinct from rheumatoid arthritis, and here damage is thought to be secondary to cartilage degeneration. In rheumatoid arthritis, immune complexes are present that consist exclusively of immunoglobulin, implying that this is both the 'antibody' (rheumatoid factor [RF]) and the 'antigen' (most commonly IgG). Autoantigenic reactivity has been localized to the constant-region (C gamma 2) domains of IgG. There is no evidence for a polypeptide determinant but carbohydrate changes have been reported. We have therefore conducted a study, simultaneously in Oxford and Tokyo, to compare in detail the N-glycosylation pattern of serum IgG (Fig. 1) isolated from normal individuals and from patients with either primary osteoarthritis or rheumatoid arthritis. The results, which required an evaluation of the primary sequences of approximately 1,400 oligosaccharides from 46 IgG samples, indicate that: (1) IgG isolated from normal individuals, patients with RA and patients with OA contains different distributions of asparagine-linked bi-antennary complex-type oligosaccharide structures, (2) in neither disease is the IgG associated with novel oligosaccharide structures, but the observed differences are due to changes in the relative extent of galactosylation compared with normal individuals. This change results in a 'shift' in the population of IgG molecules towards those carrying complex oligosaccharides, one or both of whose arms terminate in N-acetylglucosamine. These two arthritides may therefore be glycosylation diseases, reflecting changes in the intracellular processing, or post-secretory degradation of N-linked oligosaccharides.

A novel human serum lectin with collagen- and fibrinogen-like domains that functions as an opsonin

Collectins are C-type animal lectins with both collagenous and carbohydrate recognition domains and are involved in the first line host defense against pathogens. We report here a novel Ca(2+)-dependent and GlcNAc-binding lectin consisting of subunits of 35 kDa (P35) with a collagen-like sequence. When P35 is isolated from human serum, it forms a homopolymer by means of intermolecular disulfide bonding, as is the case with collectins. P35 cDNA was cloned from a human liver cDNA library, and the deduced amino acid sequence of 313 residues revealed that the mature form of P35 consists mainly of collagen- and fibrinogen-like domains. The latter contained two potential Ca(2+)-binding sites that may be involved in carbohydrate binding. The overall sequence of P35 was highly homologous to porcine ficolins alpha and beta. Northern blots of various human tissues showed that the major product of the 1.3-kilobase-long P35 transcript is expressed in liver. P35 enhanced phagocytosis of Salmonella typhimurium by neutrophils, suggesting an opsonic effect via the collagen region. P35 was found to bind to GlcNAc-conjugated bovine serum albumin, a neoglycoprotein, as well as to neoglycolipids containing complex-type oligosaccharides derived from glycoproteins, suggesting that P35 recognizes GlcNAc residues such as those found in microbial glycoconjugates and complex-type oligosaccharides. Therefore, P35 represents a new type of GlcNAc-binding lectin with structural and functional similarities to collectins involved in innate immunity.

Carbohydrate structures of the human-immunodeficiency-virus (HIV) recombinant envelope glycoprotein gp120 produced in Chinese-hamster ovary cells

The present paper describes the structures of the N-linked oligosaccharides of the human-immunodeficiency-virus (HIV) envelope glycoprotein gp120 (cloned from the HTLV-III B isolate and expressed as a secreted fusion protein after transfection of Chinese-hamster ovary cells), which is known to bind with high affinity to human T4-lymphocytes. Oligosaccharides were released from peptide by hydrazinolysis, fractionated by paper electrophoresis, high-performance lectin-affinity chromatography and Bio-Gel P-4 column chromatography, and their structures determined by sequential exoglycosidase digestions in conjunction with methylation analysis. The glycoprotein was found to be unique in its diversity of oligosaccharide structures. These include high-mannose type and hybrid type, as well as four categories of complex-type chains: mono-, bi-, tri- and tetra-antennary, with or without N-acetyl-lactosamine repeats, and with or without a core-region fucose residue. Among the sialidase-treated oligosaccharides, no less than 29 structures were identified as follows: (formula; see text) where G is galactose, GN is N-acetylglucosamine, M is mannose, F is fucose, and '+/- ' means that residues are present in a proportion of chains. The actual number of oligosaccharide structures is much greater, since before desialylation there was evidence that, among the hybrid and complex-type chains, all but 6% contained sialic acid at the C-3 position of terminal galactose residues, and partially sialylated forms of the bi- and multi-antennary chains were present. Detailed evidence for the proposed oligosaccharide sequences will be published as a supplementary paper [T. Mizuochi, M. W. Spellman, M. Larkin, J. Solomon, L. J. Basa & T. Feizi (1988) Biomed. Chromatogr., in the press].

Biliary repair and carcinogenesis are mediated by IL-33-dependent cholangiocyte proliferation

Injury to the biliary epithelium triggers inflammation and fibrosis, which can result in severe liver diseases and may progress to malignancy. Development of a type 1 immune response has been linked to biliary injury pathogenesis; however, a subset of patients with biliary atresia, the most common childhood cholangiopathy, exhibit increased levels of Th2-promoting cytokines. The relationship among different inflammatory drivers, epithelial repair, and carcinogenesis remains unclear. Here, we determined that the Th2-activating cytokine IL-33 is elevated in biliary atresia patient serum and in the livers and bile ducts of mice with experimental biliary atresia. Administration of IL-33 to WT mice markedly increased cholangiocyte proliferation and promoted sustained cell growth, resulting in dramatic and rapid enlargement of extrahepatic bile ducts. The IL-33-dependent proliferative response was mediated by an increase in the number of type 2 innate lymphoid cells (ILC2s), which released high levels of IL-13 that in turn promoted cholangiocyte hyperplasia. Induction of the IL-33/ILC2/IL-13 circuit in a murine biliary injury model promoted epithelial repair; however, induction of this circuit in mice with constitutive activation of AKT and YAP in bile ducts induced cholangiocarcinoma with liver metastases. These findings reveal that IL-33 mediates epithelial proliferation and suggest that activation of IL-33/ILC2/IL-13 may improve biliary repair and disruption of the circuit may block progression of carcinogenesis.

Phenotype, specificity, and function of T cell subsets and T cell interactions involved in skin allograft rejection

In the present study we used an adoptive transfer model with athymic nude mice to characterize the T cells involved in initiating and mediating skin allograft rejection. It was found that skin allograft rejection in nude mice required the transfer of immunocompetent T cells and that such reconstitution did not itself stimulate the appearance of T cells derived from the nude host. Reconstitution with isolated populations of Lyt-2+/L3T4- T cells resulted in the rapid rejection of MHC class I-disparate skin allografts, whereas reconstitution with isolated populations of L3T4+/Lyt-2- T cells resulted in the rapid rejection of MHC class II-disparate and minor H-disparate skin allografts. By correlating these rejection responses with the functional capabilities of antigen-specific T cells contained within the reconstituting Lyt-2+ and L3T4+ T cell populations, it was noted that skin allografts were only rejected by mice that, as shown by in vitro assessment, contained both lymphokine-secreting Th cells and lymphokine-responsive Tk cells specific for the alloantigens of the graft. The ability of two such functionally distinct T cell subsets to interact in vivo to reject skin allografts was directly demonstrated in H-Y-specific rejection responses by taking advantage of the fact that H-Y-specific Th cells are L3T4+ while H-Y specific Tk cells are Lyt-2+. Finally, the importance of in vivo interactions between functionally distinct Th/T-inducer cells and T killer (Tk)/T-effector cells in skin allograft rejection was demonstrated by the observation that normal B6 mice retain Qala and Kbm6 skin allografts because of a selective deficiency in antigen-specific Th cells, even though they contain T-effector cells that, when activated, are able to reject such allografts. Thus, the ability to reject skin allografts is neither unique to a specialized subset of T cells with a given Lyt phenotype, nor unique to a specialized subset of helper-independent effector T cells with so-called dual function capability. Rather, skin allograft rejection can be mediated by in vivo collaborations between T-inducer cells and T-effector cells, and the two interacting T cell subsets can express different Lyt phenotypes as well as different antigen specificities.

An ancient lectin-dependent complement system in an ascidian: novel lectin isolated from the plasma of the solitary ascidian, Halocynthia roretzi

Mannose-binding lectin (MBL) is a C-type lectin involved in the first line of host defense against pathogens and it requires MBL-associated serine protease (MASP) for activation of the complement lectin pathway. To elucidate the origin and evolution of MBL, MBL-like lectin was isolated from the plasma of a urochordate, the solitary ascidian Halocynthia roretzi, using affinity chromatography on a yeast mannan-Sepharose. SDS-PAGE of the eluted proteins revealed a major band of approximately 36 kDa (p36). p36 cDNA was cloned from an ascidian hepatopancreas cDNA library. Sequence analysis revealed that the carboxy-terminal half of the ascidian lectin contains a carbohydrate recognition domain (CRD) that is homologous to C-type lectin, but it lacks a collagen-like domain that is present in mammalian MBLs. Purified p36 binds specifically to glucose but not to mannose or N-acetylglucosamine, and it was designated glucose-binding lectin (GBL). The two ascidian MASPs associated with GBL activate ascidian C3, which had been reported to act as an opsonin. The removal of GBL-MASPs complex from ascidian plasma using Ab against GBL inhibits C3-dependent phagocytosis. These observations strongly suggest that GBL acts as a recognition molecule and that the primitive complement system, consisting of the lectin-proteases complex and C3, played a major role in innate immunity before the evolution of an adaptive immune system in vertebrates.

Cloning and characterization of novel ficolins from the solitary ascidian, Halocynthia roretzi

Ficolins are animal lectins with collagen-like and fibrinogen-like domains. They are involved in the first line of host defense against pathogens. Human ficolin/P35 as well as mannose-binding lectin (MBL) activates the complement lectin pathway in association with MBL-associated serine proteases. To elucidate the origin and evolution of ficolins, we separated approximately 40 kDa (p40) and approximately 50 kDa (p50) N-acetylglucosamine-binding lectins from hemolymph plasma of the solitary ascidian. Binding assays revealed that p40 recognizes N-acetyl groups in association with a pyranose ring and that p50 recognizes N-acetylglucosamine alone. Based on the amino acid sequences of the proteins, we isolated two clones each of p40 and p50 from the ascidian hepatopancreas cDNA and determined the entire coding sequences of these clones. Because all of the clones contained both collagen-like and fibrinogen-like domains, we concluded that these were homologs of the mammalian ficolin family and designated ascidian ficolins (AsFCNs). The fibrinogen-like domain of the AsFCNs shows 45.4-52.4% amino acid sequence identity with the mammalian ficolin family. A phylogenetic tree of the fibrinogen-like sequences shows that all the fibrinogen-like domains may have evolved from a common ancestor that branched off an authentic fibrinogen. These results suggest that AsFCNs play an important role with respect to ascidian hemolymph lectin activity and the correlation of different functions with binding specificity.

Improved procedure for the construction of neoglycolipids having antigenic and lectin-binding activities, from reducing oligosaccharides

Conditions have been established for the rapid and efficient conjugation of reducing oligosaccharides (di- to deca-saccharides) to dipalmitoyl phosphatidylethanolamine. The resulting neoglycolipids derived from several naturally occurring oligosaccharides and a series of N-linked high-mannose-type oligosaccharides released by hydrazinolysis from RNAase B showed specific and potent reactivities, as appropriate, with monoclonal antibodies to blood group Lewis(b), blood group A or a stage-specific embryonic (SSEA-1) antigen, or the lectin concanavalin A.

Paracrine signals regulate human liver organoid maturation from induced pluripotent stem cells

A self-organizing organoid model provides a new approach to study the mechanism of human liver organogenesis. Previous animal models documented that simultaneous paracrine signaling and cell-to-cell surface contact regulate hepatocyte differentiation. To dissect the relative contributions of the paracrine effects, we first established a liver organoid using human induced pluripotent stem cells (iPSCs), mesenchymal stem cells (MSCs) and human umbilical vein endothelial cells (HUVECs) as previously reported. Time-lapse imaging showed that hepatic-specified endoderm iPSCs (HE-iPSCs) self-assembled into three-dimensional organoids, resulting in hepatic gene induction. Progressive differentiation was demonstrated by hepatic protein production after in vivo organoid transplantation. To assess the paracrine contributions, we employed a Transwell system in which HE-iPSCs were separately co-cultured with MSCs and/or HUVECs. Although the three-dimensional structure did not form, their soluble factors induced a hepatocyte-like phenotype in HE-iPSCs, resulting in the expression of bile salt export pump. In conclusion, the mesoderm-derived paracrine signals promote hepatocyte maturation in liver organoids, but organoid self-organization requires cell-to-cell surface contact. Our in vitro model demonstrates a novel approach to identify developmental paracrine signals regulating the differentiation of human hepatocytes.

Analysis of T-cell subsets in rejection of Kb mutant skin allografts differing at class I MHC

The T-cell subpopulations which initiate and mediate tissue allograft rejection remain controversial. In the present study we attempted to identify the phenotype and function of the T-cell subset(s) primarily responsible for the rejection of skin allografts differing at a single class I locus in the major histocompatibility complex (MHC). We found that the rejection rates by B6 mice (H-2b) of four different class I mutant (Kbm) skin allografts form a distinct hierarchy. This hierarchy correlates strikingly and uniquely with the relative precursor frequencies of Lyt2+ interleukin-2-secreting T-helper cells reactive against the various Kbm mutants. To investigate the role of Lyt2+ T cells in the rejection of class I-disparate skin allografts directly, H-2b nude mice were engrafted with Kbm skin allografts and then reconstituted with L3T4+ or Lyt2+ T-cell subpopulations from syngeneic H-2b mice. Lyt2+ T cells were observed to be both necessary and sufficient for the rejection of class I-disparate Kbm skin allografts, whereas L3T4+ T cells were neither necessary nor sufficient. These results identify the Lyt2+ interleukin-2-secreting T-cell subset as the critical cell type determining the rejection rate of class I-disparate Kbm skin allografts.

Neoglycolipids as probes of oligosaccharide recognition by recombinant and natural mannose-binding proteins of the rat and man

Oligosaccharide recognition by three mammalian mannose-binding proteins was investigated by using as probes a series of structurally characterized neoglycolipids in t.l.c. binding assays. The neoglycolipids were derived from N-linked oligosaccharides of complex, high-mannose and hybrid types and from human milk oligosaccharides and simple di- and tri-saccharides. The three proteins, namely the recombinant carbohydrate-recognition domain of rat mannose-binding Protein A and the multi-subunit forms of rat and human serum mannose-binding proteins, were shown to have in common reactivity with oligosaccharide probes containing one or more non-reducing terminal N-acetylglucosamine residue(s). Substitution with galactose masks reactivity. The three proteins also bound to non-reducing terminal mannose residues in high-mannose-type oligosaccharides, non-reducing terminal fucose residues in the sequence Fuc alpha 1-4(Gal beta 1-3)GlcNAc and non-reducing terminal glucose residues in dextran oligomers; the recombinant binding domain gave consistently weaker binding. The relative reactivities with the various probes differ for each protein. Overall, the reaction patterns of the three mammalian proteins differ from that of the plant lectin concanavalin A, which showed preferential binding to the high-mannose type, weak binding to biantennary complex type and no binding to the fuco-oligosaccharide and simple oligosaccharide probes. As a group, the three mammalian proteins resemble bovine serum conglutinin and behave as lectins with rather broad sugar specificities directed at certain non-reducing terminal N-acetylglucosamine, mannose, glucose and fucose residues, but with subtle differences in fine specificities. These results illustrate the potential of neoglycolipids in studies of oligosaccharide recognition by natural and recombinant proteins of diverse biological systems.

Autoantibody activity of IgG rheumatoid factor increases with decreasing levels of galactosylation and sialylation

The occurrence of N-linked oligosaccharides lacking galactose is significantly higher than normal in serum IgG of patients with rheumatoid arthritis (RA) in whom rheumatoid factor (RF), an autoantibody against autologous IgG, has been detected. In the present study, IgGs with and without RF activity (IgGRF and non-RF IgG, respectively) were prepared from sera of RA patients, and their oligosaccharide structures were characterized in order to investigate the relationship between RF activity and glycosylation. Three IgGRF fractions and a non-RF IgG fraction were obtained based on their ability to bind to an IgG-Sepharose column. The specific RF activity, as measured by immunoassays, was highest in the IgGRF fraction, which bound most avidly to the IgG-Sepharose. When the oligosaccharides were released by hydrazinolysis, and analyzed by MALDI-TOF mass spectrometry and HPLC, in combination with sequential exoglycosidase treatment, all the IgG samples were found to contain a series of biantennary complex-type oligosaccharides. The incidence of galactose-free oligosaccharides was significantly higher in both IgGRFs and non-RF IgG from RA patients compared with IgG from healthy individuals. In all IgGRFs, the levels of sialylation and galactosylation were lower than those in non-RF IgG from RA patients; the sialylation of non-RF IgG was the same as that of IgG from healthy individuals. In addition, the decreases in galactosylation and sialylation of oligosaccharides in IgGRF correlated well with the increase in RF activity. These findings could contribute to our understanding of the mechanisms of IgG-IgG complex formation and the pathogenicity of these complexes in RA patients.

Both L3T4+ and Lyt-2+ helper T cells initiate cytotoxic T lymphocyte responses against allogenic major histocompatibility antigens but not against trinitrophenyl-modified self

This study characterizes the T helper (Th) cells that initiate primary cytotoxic T lymphocyte (CTL) responses against allogeneic and trinitrophenyl (TNP)-modified self class I major histocompatibility (MHC) determinants. We show that two distinct Th cell subsets participate in allospecific CTL responses: (a) an L3T4+,Lyt-2- class II-restricted Th cell population, and (b) an L3T4-,Lyt-2+ class I-restricted Th cell population. Both of these T cell subpopulations were shown to function in allospecific CTL responses as helper cells by their ability to show synergy with allospecific CTL precursors. Thus, primary class I allospecific CTL responses represent an immune response involving not only L3T4+ Th cells, but Lyt-2+ Th cells as well. One of the necessary functions performed by both L3T4+ and Lyt-2+ Th cell populations in allospecific CTL responses was found to be the secretion of interleukin 2. Finally, despite the many similarities between anti-allo- and anti-TNP-CTL responses, anti-TNP-CTL responses were found to be mediated by only L3T4+ Th cells, not by Lyt-2+ Th cells. Consequently, Lyt-2+ Th cells appear to be a helper cell population that is primarily involved in MHC-specific immune responses.

Tolerance induction by clonal deletion of CD4+8+ thymocytes in vitro does not require dedicated antigen-presenting cells

The cellular requirements of T cell tolerance induction in the thymus by clonal deletion was investigated by using an in vitro assay: thymocytes from mice expressing a transgenic TcR specific for lymphocytic choriomeningitis virus (LCMV) and H-2Db were co-cultured with various H-2b cell types as antigen-presenting cells in the presence of the antigenic LCMV peptide. The results revealed that all cell lines examined including embryonic and transformed fibroblasts, melanoma cells, cortical thymic epithelial cells, lymphomas and neuronal cells induced an antigen dose-dependent deletion of CD4+8+ thymocytes. Similarly, highly enriched accessory cell populations from thymus and spleen (macrophages, dendritic and cortical epithelial cells, i.e. thymic nurse cells) could induce antigen-specific depletion of immature CD4+8+ thymocytes. Depending on the cell type examined micromolar to picomolar concentration of LCMV peptide were required to induce deletion. The effectiveness of deletion by the different cell types did not correlate with their major histocompatibility class I expression level; it was, however, influenced by the presence of ICAM-1 adhesion molecules.

Structural changes in the oligosaccharide moiety of human IgG with aging

In order to elucidate the relationship between glycosylation of IgG and aging, oligosaccharide structures of human IgG purified from sera of men and women aged 18 to 73 years were investigated. Oligosaccharides were liberated quantitatively from IgG by hydrazinolysis followed by N-acetylation and were tagged with p-aminobenzoic acid ethyl ester. The oligosaccharide structures were then analyzed by HPLC in conjunction with sequential exoglycosidase digestion. All IgG samples were shown to contain a series of biantennary complex type oligosaccharides which consisted of +/-Galbeta1-4GlcNAcbeta1-2Manalpha1-6(+/-GlcNAcbeta 1-4)(+/-Galbeta1-4GlcNAcbeta1-2Man(alpha)1-3)Man(beta)1-+ ++4GlcNAcbeta1-4(+/- Fucalpha1-6)GlcNAc and their mono- and disialo glycoforms in different ratios. In female IgG samples only, the incidence of non-galactosylated oligosaccharides with non-reducing terminal GlcNAc residues increased with aging (r>0.8), whereas that of digalactosylated oligosaccharides decreased (r<-0.8). A weaker correlation was observed between aging and the incidence of neutral and monosialo oligosaccharides in female IgG (r=0.461 and r= -0.538, respectively) and between aging and the incidence of oligosaccharides with a bisecting GlcNAc in both male and female IgG samples (r=0.566 and r=0.440, respectively). In addition, a significant change with aging in the galactosylation of IgG oligosaccharides was observed in females in their thirties, fifties, and sixties (p<0.02, p<0.01, and p<0.04, respectively). These findings may contribute to our understanding of autoimmune diseases such as rheumatoid arthritis in which glycosylation is involved.

Characterization of two distinct primary T cell populations that secrete interleukin 2 upon recognition of class I or class II major histocompatibility antigens

This study has characterized the primary T cell subpopulations that secrete IL-2 in response to recognition of either class I or class II MHC encoded determinants. The addition to culture of anti-IL-2-R mAb inhibited the consumption of IL-2 by activated lymphocytes during the response period, permitting a much more accurate assessment of the amount of IL-2 produced in the response cultures. Using this response system, we found that primary T cell populations contain two IL-2-secreting T cell subsets that express reciprocal phenotypes and different MHC recognition specificities: an L3T4+, Lyt-2- T cell subset responsive to both class I and class II MHC alloantigens, and an L3T4-Lyt-2+ T cell subset responsive only to class I MHC alloantigens. The L3T4+ T cell subset expressed a broad functional response repertoire in that L3T4+ T cells were triggered to secrete IL-2 upon recognition of unmodified self-Ia determinants, allogeneic Ia determinants, and class I alloantigens presented by self-Ia determinants. The activation of L3T4+ IL-2-secreting T cells, even those responsive to class I MHC alloantigens, could be blocked completely by anti-Ia mAbs, confirming that the L3T4+ T cell subset was in fact class II restricted. In contrast, the Lvt-2+ T cell subset expressed a narrow functional response repertoire in that they were triggered to secrete IL-2 only in response to allogeneic class I MHC determinants, and were not triggered to secrete IL-2 even in response to TNP-modified self-MHC determinants. The specificity of Lyt-2+ IL-2-secreting T cells for class I MHC allodeterminants was confirmed by the observations that: (a) their activation could be blocked completely by anti-class I mAbs, (b) they could be triggered by Ia- cell lines which expressed class I MHC alloantigens and possessed accessory function, and (c) they responded to class I MHC alloantigens but failed to respond to class II MHC alloantigens, even in the presence of exogenously added second signals that circumvented the requirement for alloantigen-bearing accessory cells. Finally, the frequency of primary Lyt-2+ T cells that secreted IL-2 in response to class I (Kbm1) MHC alloantigens was shown to be only minimally lower than that of L3T4+ T cells that secreted IL-2 in response to class II (I-Abm12) MHC alloantigens.(ABSTRACT TRUNCATED AT 400 WORDS)

Benign infantile convulsions associated with mild gastroenteritis: a retrospective study of 39 cases including virological tests and efficacy of anticonvulsants

Benign convulsions associated with mild gastroenteritis (CwG) are a commonly observed disorder in Asia, especially in infants and seniors. Here, we describe a retrospective study about the clinical features of CwG in 62 children hospitalized at St. Mary's Hospital (Kurume City, Japan) between January 1, 2000 and March 31, 2006, and further evaluate the efficacies of various anticonvulsant treatments for patients with CwG due to either rotavirus or norovirus. Causative diarrheal viruses were detected in 71% of the fecal specimens tested; 30 patients were positive for rotavirus, nine patients were positive for norovirus, two patients were positive for sapovirus, two patients were positive for adenovirus, and one patient was positive for coxackievirus A4. The age of onset for patients with norovirus-positive CwG (16.7+/-2.7 months) was significantly lower than that of patients with rotavirus-positive CwG (23.0+/-8.7 months). The duration of the seizures due to norovirus infection (11.8+/-12.0 h) was significantly longer than that due to rotavirus infection (4.9+/-5.7 h). There were no significant differences between the two groups with regard to the results of blood chemistry analysis, including the concentrations of serum electrolytes, blood glucose levels, and liver function tests. In this preliminary study, the duration of seizures in patients with CwG due to norovirus that was treated with carbamazepine was significantly shorter than the duration of seizures in the patients treated with another anticonvulsant (phenobarbital). Further randomized controlled studies are required to clarify the efficacies of the various anticonvulsants for patients with CwG.

Both cathepsin B and cathepsin D are necessary for processing of ovalbumin as well as for degradation of class II MHC invariant chain

The effect of highly selective inhibitors of cathepsins on the processing of ovalbumin (OVA) and the presentation of an OVA-derived antigenic peptide (OVA323-339) by antigen presenting cells (APC) was investigated. Both CA-074 (a specific inhibitor of cathepsin B) and pepstatin A (a specific inhibitor of cathepsin D) showed an inhibitory effect on the IL-2 production from an OVA-specific, I-Ad-restricted helper T (Th) cell clone upon stimulation with OVA presented by the I-Ad-positive APC. In contrast, the presentation of the antigenic epitope, OVA323-339, to the same Th clone was not inhibited by either CA-074 or pepstatin A alone, nor even by the mixture of both inhibitors. When APC were treated with cathepsin inhibitor for 24 h, and then antigen and Th were added to the culture, the presentation of not only OVA but also an OVA-derived antigenic peptide was inhibited by either cathepsin inhibitor alone. In addition, the expression of invariant chain on APC was significantly augmented by the pretreatment of APC with either cathepsin inhibitor. Two main conclusions are drawn from these results. First, not only aspartyl protease, such as cathepsin D, but also thiol protease, such as cathepsin B, is involved in antigen processing by APC. Second, both cathepsin B and cathepsin D are necessary for degradation of the invariant chain (Ii) from the MHC class II alpha beta heterodimer in endosomes in order to express functional MHC class II molecules for binding antigenic peptides.