A promiscuous T cell hybridoma restricted to various I-A molecules

In a previous study, we identified T cell receptor and major histocompatibility complex (MHC) contact sites on the pigeon cytochrome c p43-58 peptide. Positions 46 and 54 of p43-58 were shown to be the MHC-binding sites. Specific amino acids were identified on the MHC-binding sites which bound to the relevant I-A molecule. In the present study, using NOD (I-A^g7) mice, we established a T cell hybridoma, NOE33-1-2, specific for a p43-58 analog 46R50E54A with arginine (R) and alanine (A) at positions 46 and 54, respectively. Interestingly, NOE 33-1-2 recognized 46R50E54A in the presence of not only I-A^g7, but also I-A^{d, s, u and v}. In contrast to previous reports that promiscuous T cells were able to recognize peptide antigens with various HLA-DR or I-E molecules consist of monomorphic α and polymorphic β chains, the promiscuous T cell clone NOE33-1-2 recognized peptides with various I-A molecules lacking the monomorphic chain.     

Molecular defects in the beta-globin gene identified in different ethnic groups/populations during prenatal diagnosis for beta-thalassemia: a Malaysian experience

Abstract   β-thalassemia is the most-common genetic disorder of hemoglobin synthesis in Malaysia, and about 4.5% of the population are heterozygous carriers of the disorder. Prenatal diagnosis was performed for 96 couples using the Amplification Refractory Mutation System and Gap-Polymerase Chain Reaction. We identified 17 β-globin defects-initiation codon for translation (T-G), -29 (A-G), -28 (A-G), CAP +1 (A-C), CD 8/9 (+G), CD 15 (G-A), CD 17 (A-T), CD 19 (A-G), Hb E (G-A), IVS1-1 (G-T), IVS1-5 (G-C), CD 41/42 (-CTTT), CD 71–72 (+A), IVS2-654 (CT), poly A(A-G), 100-kb ^Gγ(^Aγδβ)° and 45-kb Filipino deletions. The 192 β-alleles studied comprised Chinese (151 patients), Malay (21), Orang Asli from East Malaysia (15), Filipino (1), Indian (1), Indonesian Chinese (2), and Thai (1). In the Chinese, 2 β-globin defects at CD 41/42 and IVS2-654 were responsible for 74% of β-thalassemia. β-mutations at CD 19, IVS1-1 (G-T), IVS1-5, poly A, and hemoglobin E caused 76% of the hemoglobin disorders in the Malays. The Filipino 45-kb deletion caused 73.3% of bthalassemia in the Orang Asli. Using genomic sequencing, the rare Chinese β-mutation at CD 43 (G-T) was confirmed in 2 Chinese, and the Mediterranean mutation IVS1-1 (G-A) was observed in a Malay β-thalassemia carrier. The β-globin mutations confirmed in this prenatal diagnosis study were heterogenous and 65 (68%) couples showed a different globin defect from each other. The use of specific molecular protocols has allowed rapid and successful prenatal diagnosis of β-thalassemia in Malaysia.     

DQCAR 113 and DQCAR 115 in combination with HLA-DRB1 alleles are significant markers of susceptibility to rheumatoid arthritis in the Korean population

We have investigated HLA region microsatellite polymorphisms in rheumatoid arthritis (RA) which are known to be associated with HLA class II alleles in the Korean population. Ninety patients with RA and 106 controls were employed for this study, in which TAP1CA, DQCAR, D6S273, HLA-DRB1, -DQA1 and -DQB1 allele typing were performed. DQCAR 113 (RR = 3.2, P<0.0002), DQCAR 115 (RR = 3.6, P<0.0001) and heterozygous DQCAR 113/115 (RR = 11.2, P<0.0001) frequencies were significantly increased in the RA group compared with the control group. The HLA-DRB1 genotypes of patients who had DQCAR 113/115 alleles were defined as DRB1*04 and/or DRB1*09. There was no significant difference between RA and controls in D6S273 and TAP1CA allele frequencies. We demonstrated that HLA-DRB1*0405 (RR = 6.6, P<10(-6)), DQA1*03 (RR = 5.2, P<10(-6)), DQB1*04 (RR = 3.5, P<0.002) alleles were useful markers of susceptibility to RA in Koreans. The frequency of HLA-DRB1*0405 was higher in DQCAR 113 allele-positive RA (68.1%) than in DQCAR 113 allele-negative (16.3%) and total RA (43.3%) groups, and the susceptibility risk of DQCAR 113 allele to RA was more increased in the DRB1*0405-positive group (RR = 5.5, P<0.04). On the other hand, DQCAR 115 allele was more significantly associated with susceptibility to RA in HLA-DRB1*0405-negative patients (RR = 5.1, P<0.0005), and the association between RA and HLA-DRB1*0405 was also significantly associated with DQCAR 115 allele-negative patients (RR = 13.2, P<0.00001) as compared with DQCAR 115 allele-negative control groups. HLA-DRB1*0405-DQA1*03-DQCAR113-DQB1*03 haplotype showed high relative risk value (RR= 17.7, P<0.0002). In conclusion, the DQCAR allele in combination with HLA class II, especially DR, is probably a useful risk marker for RA susceptibility in the Korean population.     

Expression pattern of Popdc2 during mouse embryogenesis and in the adult.

The Popdc2 gene is a member of the Popeye domain containing gene family encoding membrane proteins with prominent expression in striated and smooth muscle tissue. After introducing a LacZ reporter gene into the Popdc2 locus, expression was studied during embryonic development and postnatal life. At embryonic day (E) 7.5, expression was present in cardiac and extraembryonic mesoderm. At E10.5, expression was found in heart, somites, and mesothelial cells lining the coelom. At E12.5, expression was present in the coelomic mesothelium, pericardial and myocardial layer of the heart, skeletal muscle, bladder, gut, and umbilical vessels. Postnatal expression was found in cardiac and skeletal muscle and in the smooth muscle layer of colon, rectum, and bladder. In the stomach, Popdc2 was exclusively present in the pyloric epithelium. In conclusion, Popdc2 is expressed in various muscle and nonmuscle cell types during embryonic development and in postnatal life.     

The inhibitory NK cell receptor CD94/NKG2A and the activating receptor CD94/NKG2C bind the top of HLA-E through mostly shared but partly distinct sets of HLA-E residues

The human non-classical MHC class I molecule HLA-E is a ligand for both an inhibitory NK cell receptor (CD94/NKG2A) and an activating receptor (CD94/NKG2C). To identify HLA-E surface recognized by both receptors, especially to determine if both receptors recognize the same epitope, we made a series of individually Ala-substituted HLA-E proteins and analyzed their binding to CD94/NKG2A orCD94/NKG2C. Eight HLA-E mutations that significantly impaired HLA-E binding to CD94/NKG2A are all found in the top of alpha1/alpha2 domain of HLA-E. These results suggest that CD94/NKG2A binds a HLA-E surface equivalent to a NKG2D binding site on MICA. Of the eight mutations that impaired HLA-E binding to CD94/NKG2A, six significantly impaired HLA-E binding to CD94/NKG2C suggesting that CD94/NKG2C also binds a similar surface of HLA-E. Unexpectedly, the two HLA-E mutations (D69A and H155A) selectively abrogated HLA-E binding to CD94/NKG2A, not largely affected CD94/NKG2C. These results indicate that a mostly shared, but partly distinct set of HLA-E residues is discriminated by the two receptors.     

Production of CA125 by human lung cancer cell lines

CA125, which until recently was considered an ovary specific tumor marker, is elevated in the serum of patients with many pathological conditions, including lung cancer. In order to investigate the production of CA125 by human lung cancer cell lines, cell culture and immunochemical staining were performed in three cell lines. Our results showed the cell surface expression of CA125 in both adenocarcinoma and large cell carcinoma cell lines and the production of CA125 in culture medium. This is considered as evidence for in vitro production of CA125 by human lung cancer, and suggests that CA125 elevation is not only the result of ovarian cancer but may be due to other pathological conditions, including lung cancer.     

Chronic mucocutaneous candidiasis. II. Class and subclass of specific antibody responses in vivo and in vitro

Patients with chronic mucocutaneous candidiasis (CMC) succumb to persistent infections with the opportunistic yeast Candida. Impaired cell-mediated responses to Candida have been repeatedly reported while antibody responses were mostly found to be normal. The underlying defect remains poorly understood. It has recently been shown that CMC patients are also susceptible to infections with encapsulated bacteria, and may have associated IgG2 and IgG4 deficiency. Our previous studies demonstrated altered cytokine production in CMC patients. As cytokines can influence production and isotype of specific antibody, in 10 patients with CMC we measured the levels and isotype distributions of serum antibodies to Candida antigens (CAg), pneumococcal polysaccharide (PPS) and tetanus toxoid (TT) antigens. Peripheral blood lymphocytes were also stimulated in culture and the antibodies made in vitro were measured. Our data demonstrated that in vivo, CMC patients had very high levels of IgG and IgA CAg-specific antibodies. CAg-specific and PPS-specific IgG1 was markedly higher than in controls. Children but not adults with CMC had significantly lower levels of IgG2-specific antibody to CAg and PPS compared with age-matched controls. Patients had significantly higher levels of IgG3-specific antibody to all three antigens tested. These findings were in accordance with increased total IgG and IgG3 levels seen in CMC patients. In vitro, CMC patients, particularly children, did not respond as frequently to antigen stimulation as did their healthy controls. The level of specific antibody produced was also lower to all antigens tested, as was the amount of total immunoglobulins following antigenic and particularly mitogenic stimulation. Addition of interferon-alpha (IFN-α) or IFN-γ to cultures had variable, sometimes marked, effects. Our results demonstrate that CMC patients manifest subtle alterations in specific antibody responses to CAg, PPS and TT, which are most pronounced in children. This may relate to altered cytokine production also seen in these patients.     

A case of progression from type II cryoglobulinaemia to Waldenstrom’s macroglobulinaemia in a patient with chronic hepatitis C

In recent years, much interest has been generated over the potential of human embryonic stem cells in transplantation medicine. The ground-breaking study of Fraidenraich and colleagues conclusively demonstrated that rescue of lethal cardiac defects in Id knockout mutant mouse embryos was not due to transplanted embryonic stem cells giving rise to functional new tissues within the defective embryonic heart. Instead, there is indirect evidence that the observed therapeutic effect was due to various secreted factors emanating from the transplanted cells. This therefore introduces the exciting prospect of utilizing human embryonic stem cells as "catalysts" to promote biological repair and regeneration in transplantation therapy. Nevertheless, the immunological barrier against allogenic transplantation, as well as the teratogenic potential of human embryonic stem cells poses major technical challenges. A possible strategy to overcome the immunological barrier may be to impose a temporary regimen of immunosuppressive drugs followed by their gradual withdrawal, once adequate tissue regeneration has been achieved. Other more novel alternatives include the use of microencapsulation to block interaction with the transplant recipient's immune system, and co-transplantation with bone marrow-derived mesenchymal stem cells, which have been demonstrated to possess immuno-suppressive properties. The teratogenic potential of human embryonic stem cells could possibly be alleviated by directing the differentiation of these cells to specific lineages prior to transplantation, or through mitotic inactivation. Co-transplantation with autologous adult stem cells may represent a novel strategy to further enhance the "catalytic" effects of human embryonic stem cells. The various factors secreted by human embryonic stem cells could then have a concentrated localized effect on relatively large numbers of co-transplanted autologous adult stem cells, which may in turn lead to enhanced repair and regeneration of the damaged tissue or organ. This new therapeutic strategy needs to rigorously investigated, in view of its potentially important clinical applications.     

Increase in the proportion of fast-twitch muscle fibres by sprint training in males

Fifteen male physical education students were studied. The subjects trained for 4–6 weeks, 2–3 days per week, on a mechanically braked bicycle ergometer. A training session consisted of repeated 30-s ‘all-out’ sprints on a Wingate bicycle ergometer, on which the brake band of the flywheel was loaded with 75 g kg^-1 body wt, with rest periods of 15–20 min between consecutive sprints. Thigh muscle biopsies were taken before and after the training period and were analysed for fibre types using a myofibrillar ATPase stain. The proportion of type I fibres decreased from 57 to 48% (P < 0.05) and type IIA fibres increased from 32 to 38% (P < 0.05). This study indicates that it is possible to achieve a fibre type transformation with high-intensity training. The effect of two-legged ‘sprint’ training on muscle fibre type composition may be related to a changed pattern of muscle fibre activation (e.g. an increased stimulation frequency). A change in fibre activation frequency may induce an increased synthesis of type II fibre myosin (fast myosin). Hormonal influences such as enhanced adrenergic stimulation of the muscle fibres cannot be excluded as a contributing factor, however.