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Biomedical subjects

K Kano

Publications and source records attributed to K Kano.

At least 181 records · Page 10Linked to original sources
PubMed1989

The structure and expression of genes encoding serologically undetected HLA-C locus antigens.

Approximately 20 to 50% individuals in every race are untypable by human alloantisera for at least one allele of HLA-C locus and the surface expression of HLA-C locus Ag in such an individual (HLA-C blank Ag) remains unknown. To investigate the structure and the surface expression of HLA-C blank Ag, two genes (Cb-1 and Cb-2) encoding HLA-C blank Ag were cloned and their primary structures were determined and compared with other HLA-C locus genes. The similarity of amino acids between Cb-1 and Cw1 was the highest among HLA-C locus genes previously published. Five amino acid substitutions between these molecules were shown to be located on the beta-strand of alpha 1 and alpha 2 domains, suggesting that they might change the conformational allodeterminants on the alpha-helical region of Cw1 which were recognized by antibodies. On the other hand, Cb-2 was the closest to Cw2.2. Six of nine amino acid substitutions between these molecules were observed on alpha 1 and alpha 2 domains, whereas three other substitutions were located on the leader peptide, the alpha 3 domain and the transmembrane. Two substitutions (residues 73 and 163) of the alpha-helical region of the alpha 1 and alpha 2 domains and one (residue 16) of exposed loop may make new allodeterminants which are not recognized by anti-Cw2 sera as well as other alloantisera. The surface expression of these genes was examined on transfected mouse L cells and human B cell line. Both gene products were expressed stably on the surface of these cells. These results suggest that HLA-C blank Ag are most probably expressed on cells in HLA-C blank individuals and that the primary structures of these Ag, which were not detectable by the available alloantisera, may be incapable of generating corresponding alloantibodies.

Amino Acid Sequence↗
PubMed1989

Structure of the alpha 1 subunit of horse Na,K-ATPase gene.

Genomic DNA for Na,K-ATPase alpha 1 subunit was obtained from libraries of horse kidney genomic DNA in Charon 4A and in EMBL3 bacteriophages by screening with the full sized cDNA probe of the alpha 1 subunit of rat Na,K-ATPase as probe. The gene spans 30 kb and consists of 23 exons and 22 intervening sequences. Intron-exon boundaries were analyzed. The protein-coding nucleotide sequence encodes 1016 amino acids with an Mr of 112,264. The putative amino acid sequence of horse alpha 1 is 96-97% homologous to those of other mammalian species.

Amino Acid Sequence↗
PubMed1989

HLA-B51 and HLA-Bw52 differ by only two amino acids which are in the helical region of the alpha 1 domain.

Genes encoding the serologically cross-reactive HLA-B51 and HLA-Bw52 molecules were isolated and the exons sequenced. HLA-B51 genes obtained from Caucasian and Oriental individuals were identical. HLA-Bw52 differs from HLA-B51 by four nucleotide substitutions in exon 2 encoding the alpha 1 domain. These comprise one isolated silent substitution in codon 23 and a cluster of three coding substitutions in codons 63 and 67. Amino acid substitutions of N----E at position 63 and F----S at position 67 are the only differences between HLA-B51 and HLA-Bw52 and these residues are postulated to form HLA-B51 specific epitopes. HLA-B51 could have been formed from HLA-Bw52 by the combination of a genetic exchange with HLA-B8 and a point mutation. Similarity of HLA-B51 and HLA-Bw52 with HLA-Bw58 suggest they also share a common ancestor.

Amino Acid Sequence↗
PubMed1989

Allo-class I-reactive CD4-CD8- T cell hybridomas recognize the conformational change of class I molecule resulting from the exchange of the alpha 3 domain.

H-2Kb-reactive, interleukin (IL) 2-producing T cell hybridomas possessing neither CD8 nor CD4 molecules were employed for the study of allorecognition on interspecies hybrid antigens by T cells in the absence of an influence of these accessory molecules. Both HTB176.10 and HTB177.2 T cell hybridomas reacted with KbKbB7 hybrid antigens as well as Kb antigens and they produced more IL2 in response to Kb antigens than KbKbB7 hybrid antigens. IL2 production of these T cell hybridomas was dependent on the surface expression level of Kb molecules on stimulators. Therefore, L cells expressing almost equivalent levels of Kb or hybrid antigens were selected for further functional studies by these T cell hybridomas. They apparently produced less IL2 in response not only to interspecies hybrid antigens but also to interspecies hybrid antigens in response to Kb antigens. These results indicated that T cell hybridomas recognized the conformational change of class I molecule resulting from the exchange of the alpha 3 domain via their T cell receptors.

Amino Acid Sequence↗
PubMed1989

The structure of HLA-B35 suggests that it is derived from HLA-Bw58 by two genetic mechanisms.

The primary structure of HLA-B51 and HLA-Bw52 suggested that HLA-B51 was derived from HLA-Bw52 by the combination of a genetic exchange with HLA-B8 and a point mutation. To investigate the evolution of the HLA-B5 cross reactive group, the HLA-B35 gene was cloned and the primary structure was determined. HLA-B35 is identical to HLA-Bw58 except in the alpha 1 domain. The alpha 1 domain of HLA-B35 except Bw4/Bw6-associated amino acids is identical to that of HLA-B51, which was suspected to be an intermediate gene between HLA-B51 and HLA-Bw52. These data suggest that HLA-B35 has evolved from HLA-Bw58 in two steps; an in vivo replacement of the alpha 1 domain with HLA-B51 and genetic exchange with one of the HLA-Bw6 genes. These three genes and HLA-Bw58 are postulated to share a common ancestor. As HLA class I molecules of a serologically cross-reactive group (CREG) have limited polymorphism, we suspected they might have evolved from a common ancestor. In fact, the structures of HLA-B51 and HLA-Bw52 in HLA-B5 CREG demonstrate that they differ by only two amino acids. Both substitutions are in the helical region of the alpha 1 domain and suggest that HLA-B51 could be derived from HLA-Bw52 by the combination of a genetic exchange with HLA-B8 and a point mutation (Hayashi et al. 1989). HLA-B35 belongs to the HLA-B5 CREG and is serologically related to Bw6, while HLA-B5 (B51 and Bw52) is related to Bw4. HLA-B35 is serologically closer to HLA-B51 than to HLA-Bw52. Therefore, we have cloned a genomic gene of HLA-B35 and determined its structure to study further the evolution of the HLA-B5 family.

Amino Acid Sequence↗
PubMed1989

Overexpression of src family gene for tyrosine-kinase p59fyn in CD4-CD8- T cells of mice with a lymphoproliferative disorder.

Overexpression of a src family gene, lck, has been associated with differentiation of the murine thymic lymphoma line LSTRA. Recent findings by several groups strongly suggest a functional role for the gene product p56lck protein-tyrosine kinase (PTK) in the activation of normal T cells. A single recessive gene, lpr or gld, induces a lymphoproliferative disorder concomitant with autoimmune disease in mice. In this study, a 10-fold elevated activity of PTK encoded by fyn, another src family gene, was demonstrated in CD4-CD8- T cells in mutant mice. The increased PTK activity was consistent with overexpression of fyn mRNA. The elevated fyn mRNA expression appeared to be a characteristic of CD4-CD8- T cells, since it was not observed in normal T cells at any stage of differentiation. The fact that fyn mRNA expression was markedly induced in normal T cells by mitogenic stimulation with anti-T3 epsilon antiserum supports the possibility that p59fyn PTK is a signal-generating molecule in T cells. Thus, our findings provide insight into the physiological role for a src gene family kinase in T-cell development and contribute to a better understanding of the molecular mechanisms of disease-inducing recessive genes.

Animals↗
PubMed1989

Analysis of xenoantigenicity of HLA class I molecules by a complete series of human-mouse hybrid genes.

To investigate the xenoantigenicity of HLA class I antigens, a complete series of human/mouse chimeric major histocompatibility complex class I genes was constructed by using the human HLA-B7 and mouse H-2Kb genes. All of these hybrid antigens were stably expressed on L cells at high levels. Nine anti-HLA class I monoclonal antibodies, including 5 monomorphic, 3 broad polymorphic, and 2 specific polymorphic ones, were tested by binding to these cell lines. Our data suggest that the alpha 2 domain of HLA-B7 plays an important role in the formation of the antigenic determinants recognized by all of the anti-HLA class I mAbs tested. However, the antigenic determinants of the monomorphic mAbs were complex. In some cases, all of the three extracellular domains were required for expression of the epitope. The location of xenoimmunogenic site of HLA-B7 antigen was also examined by immunizing (B6xC3H)F1 and C3H mice with the parental and hybrid antigens. Our data suggest that the alpha 1 and alpha 2 domains of HLA-B7 must be expressed together for production of antibodies against monomorphic determinants of HLA class I antigens, while the alpha 3 alone can induce xenoantibodies in (B6xC3H)F1 mice but not in C3H mice.

Animals↗
PubMed1989

Risk factors in chronic obstructive pulmonary malfunction and "chronic bronchitis" symptoms in Beijing district: a joint study between Japan and China.

A cross sectional study of risk factors in respiratory diseases was carried out in August 1986, in Beijing, China. Inhabitants greater than or equal to 40 years old were selected at random from a rural area, a residential area and an industrial area, using a two stage sampling method. The analysis presented here is based on the sample population of adults who (1) were prepared to be interviewed, using the British Medical Research Council's questionnaire translated into Chinese (n = 3423) and (2) had lung function measurements at the same time (n = 3373). Obstructive lung disease was defined as forced expiratory volume in 1s (FEV1) less than 68% of forced vital capacity (FVC). Seven variables were considered as potential risk factors or confounding factors: area of residence, sex, age, cigarette smoking, history of respiratory disease, socio-economic status and familial component. A modified binary variable regression method developed by Feldstein was used for the adjustment of rate ratios. The adjusted prevalence of obstructive lung disease was highest in the rural area and lowest in the residential area(s). An increase in age, cigarette smoking, low socio-economic status and positive history of respiratory diseases were associated with significantly higher rates of impaired pulmonary function. The other measured factors did not appear to be related to impaired pulmonary function.

Adult↗
PubMed1989

Production of monoclonal antibody to thyroglobulin from malignant thyroid carcinoma.

In this study, the production of anti-human thyroglobulin (Tg) monoclonal antibodies was attempted to detect Tg levels in serum and to study the localization of thyroid metastases in patients with thyroid-gland ablation. As a result four clones of hybridoma cell lines were obtained. By means of enzyme immunoassay (EIA) and immunohistochemical method, it was found that one of them, 2G4, produced a monoclonal antibody recognizing a malignant structural change of Tg and other three clones produced monoclonal antibodies recognizing not only the normal human Tg but also the malignant Tg. Our monoclonal antibody, 2G4, will be a hopeful reagent for the diagnosis in thyroid carcinoma.

Antibodies, Monoclonal↗
PubMed1988

Nanosecond pulse fluorometry of conformational change in phenylalanine hydroxylase associated with activation.

Conformational change in rat liver phenylalanine hydroxylase associated with activation by phenylalanine or N-(1-anilinonaphth-4-yl)maleimide was investigated by measuring fluorescence spectra and fluorescence lifetimes of tryptophanyl residues as well as the probe fluorophore conjugated with SH groups of the hydroxylase. The fluorescence spectrum of tryptophan exhibited its maximum at 342 nm. It shifted by 8 nm toward longer wavelength accompanied by an increase in its intensity, by preincubation with 1 mM phenylalanine. The fluorescence intensity of tryptophan increased by 36% upon the activation. On the other hand, the binding of (6R)-L-erythro-tetrahydrobiopterin, a natural cofactor of the enzyme, induced a decrease in the fluorescence intensity by 79% without a shift of the maximum wavelength. The fluorescence lifetime of tryptophan of phenylalanine hydroxylase exhibited two components with lifetimes of 1.7 and 4.1 ns. The values of the lifetimes changed to 1.4 and 5.6 ns, respectively, upon the activation. It is considered that the change in the longer lifetime is correlated with the shift of the emission peak upon the activation. The values of both the lifetimes decreased to 0.64 and 3.6 ns upon the binding of (6R)-L-erythro-tetrahydrobiopterin, which is coincident with the decrease in the fluorescence intensity. Conjugation of N-(1-anilinonaphth-4-yl)maleimide with SH of phenylalanine hydroxylase brought about a decrease in both the fluorescence intensity and the value of the shorter lifetime of the tryptophanyl residues, while the longer lifetime remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Ontogeny and function of B220+ L3T4+ T-cell subset of MRL/Mp-lpr/lpr mice.

T-cell-enriched populations obtained from lymph nodes (LNs) of 4-month-old MRL/Mp-lpr/lpr (MRL-lpr), C3H/HeJ-lpr/lpr (C3H-lpr), and C3H/HeJ-gld/gld (C3H-gld) mice were studied for the expression of B220, L3T4, and Lyt 2 antigens. A new B220+ L3T4+ phenotype was demonstrated in T-cell populations of these mice by two-color flow cytometry with phycoerythrin-conjugated monoclonal antibodies (MoAb) to L3T4 and FITC-anti-B220 MoAb. The generation of the T subset was apparently under the influence of the lpr or gld gene, since it could not be demonstrated in T-cell-enriched populations of MRL/Mp- +/+ and normal C3H mice. The expression level of L3T4 antigen on the T subset was lower than that on B220- L3T4+ cells, while the level of B220 antigen was similar to that of B220+ L3T4- or B220+ Lyt 2- cells. The B220+ L3T4+ phenotype appeared in LNs and spleens, but not in thymuses, of MRL-lpr mice as early as 2 months of age. Its proportion to whole LN T cells at this age was equivalent to that observed in 4-month-old mice. Functional studies on FACS-sorted cell populations revealed that the T subset similar to B220+ L3T4- cells possessed deficiencies in the IL-2-IL-2 receptor system. The appearance of the T subset with an intermediate phenotype and its functional defects suggests that lpr and gld genes in these autoimmune mice exert their influences on the ontogeny and function of L3T4+ T cells and contribute to the induction of early lupus.

Animals↗
PubMed1988

Mode of induction of long-term depression at parallel fibre--Purkinje cell synapses in rabbit cerebellar cortex.

In a superficial folium of the dorsal paraflocculus of high decerebrate rabbits, extracellular unitary spikes were recorded from a Purkinje cell, while two parallel fibre beams impinging onto that Purkinje cell were separately stimulated in the molecular layer. Climbing fibre afferents were stimulated at the contralateral inferior olive. Quisqualate was ionophoretically applied to the dendrite of the Purkinje cell intersecting one of the stimulated parallel fibre beams (test beam). Long-term depression (longer than 45 min) occurred in Purkinje cell responsiveness to the test beam, but not to the other beam (control beam), when quisqualate was applied for 4 min in conjunction with 2 Hz stimulation of climbing fibres. This effect was completely abolished by simultaneous application of a glutamate blocker, kynurenate, during conjunctive quisqualate-climbing fibre stimulation. Application of quisqualate alone caused a small degree of depression in parallel fibre-Purkinje cell transmission. This effect was abolished when spontaneous activity of climbing fibres was blocked by injection of tetrodotoxin or lidocaine to the contralateral inferior olive, and therefore was due to conjunction of quisqualate with spontaneous climbing fibre inputs that normally occurred at 0.5-1.2 Hz. These findings suggest that the occurrence of long-term depression is strictly dependent on conjunction of climbing fibre activity with quisqualate receptor activation.

Action Potentials↗
PubMed1988

Heterophile Hanganutziu-Deicher antigen in ganglioside fractions of human melanoma tissues.

Gangliosides were purified from melanoma tissue extracts obtained from 5 patients. GM3 and GD3 were identified as the major components in ganglioside fractions of the melanoma tissues. Following thin-layer chromatography, enzyme immunostaining with Hanganutziu-Deicher (H-D) antigen-specific chicken antisera demonstrated the presence of NeuGc-neolactotetraosylceramide (H-D5) and NeuGc-lacto-N-norhexa-osylceramide (H-D7) in all 5 melanoma extracts.

Antibodies, Heterophile↗