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Biomedical subjects

T Honjo

Publications and source records attributed to T Honjo.

At least 271 records · Page 15Linked to original sources
PubMed1988

Expression of functional interleukin-2 receptors in human light chain/Tac transgenic mice.

The growth of mature T lymphocytes is regulated by interaction between interleukin-2 (IL-2) and its receptor. Three distinct binding sites for IL-2, namely low- (Kd 10 nM), intermediate- (Kd 100 pM) and high- (Kd 10 pM) affinity sites, have been found on human and primate T lymphocytes. Chemical crosslinking of labelled IL-2 to human T cells shows that two polypeptide chains, p55 (L chain) and p75 (H chain), bind IL-2 with low and intermediate affinities respectively. The high-affinity binding was shown to arise from ternary complex formation of IL-2, L and H chains. Construction of mutants of the L-chain complementary DNA indicated that the L chain is not directly involved in growth signal transduction. Nevertheless, expression of the IL-2 receptor L chain is tightly regulated by antigen or mitogen stimulation. To investigate the L chain function, we have produced transgenic mice using human L-chain cDNA of the IL-2 receptor under the control of a constitutive promoter. Studies on the L-chain transgenic mice showed that functionally active IL-2 receptors with high affinity were expressed on unstimulated spleen and thymus cells. The results indicate that the H chain of the IL-2 receptor is constitutively expressed in T cells.

Animals↗
PubMed1988

Dispersed localization of D segments in the human immunoglobulin heavy-chain locus.

We have studied the organization of the human immunoglobulin heavy-chain genes by pulse field gel electrophoresis as well as by isolation of cosmid clones. The total length of the heavy-chain variable region locus was estimated to be approximately 3000 kb. We found that D segments including a recently isolated D5 segment were dispersed among VH segments. We identified a pseudo V segment 18 kb 3' to the D5 segment in isolated cosmid clones. A 300 kb fragment produced by MluI digestion contained VH, D, JH segments and the distance between VH and D was estimated to be approximately 240 kb. Overlapping cosmid clones containing the human D1, D2, D3, D4, JH, Cmu and C delta genes were isolated. Restriction maps of these regions indicated that the distance between D and JH is about 22 kb. A partial restriction map of the VH locus was constructed using the pulse field gel electrophoresis technique and deletion of VH segments in B cells.

Amino Acid Sequence↗
PubMed1988

Fibroblast-dependent growth of mouse mast cells in vitro: duplication of mast cell depletion in mutant mice of W/Wv genotype.

In spite of the apparent depletion of mast cells in tissues of mutant mice of W/Wv genotype, cells with many features of mast cells do develop when bone marrow cells of W/Wv mice are cultured in the presence of pokeweed mitogen-stimulated spleen cell-conditioned medium (PWM-SCM). In order to resolve this discrepancy and facilitate the analysis of the W mutation, we attempted to establish an in vitro system in which the in vivo defect of W/Wv mice can be reproduced. Cultured mast cells (CMC) were developed from bone marrow cells of either W/Wv or congenic +/+ mice, and then co-cultured with NIH/3T3 mouse fibroblasts in media supplemented only with fetal calf serum (i.e., in the absence of PWM-SCM). Under this condition, CMC from +/+ mice continued to divide and were maintained for more than 4 weeks. The supportive effect of NIH/3T3 cells required close-range interactions with CMC and was not due to synthesis of the known mast cell growth factors, interleukins 3 and 4. By contrast, CMC from W/Wv mice were not maintained, and the number of mast cells remaining after 4 weeks of co-culture was only 1% of the normal +/+ counterparts. Thus, the humoral factor-independent and cell contact-dependent system presented here revealed the intrinsic defects in growth and differentiation of CMC derived from W/Wv mice and might be useful for biochemical and molecular analysis of the gene product(s) encoded at the W locus.

Animals↗
PubMed1988

Mouse immunoglobulin allotypes: multiple differences between the nucleic acid sequences of the IgEa and IgEb alleles.

To clarify the allotypic difference of the IgE antibody molecule, we determined the complete nucleotide sequence of the genes encoding the constant portion of mouse IgE of a (BALB/c) as well as b (B10.A) allotypes. A comparison of the sequences revealed that there were 12 single-base changes: 2 single-base changes in CH1 and CH2, 3 in CH3, and 7 in CH4. Five of them were silent changes, but seven resulted in amino acid substitutions. Although the silent changes are scattered through CH1 to CH4, the nonsilent substitutions were found only in CH3 (two substitutions) and CH4 (five). The allotypic determinant(s) that conventional antisera detect most likely reflects an amino acid difference(s) in CH3 and/or CH4.

Alleles↗
PubMed1988

Multiple recombinational events in primate immunoglobulin epsilon and alpha genes suggest closer relationship of humans to chimpanzees than to gorillas.

Immunoglobulin epsilon and alpha genes of chimpanzee and gorilla were isolated and their structures were compared with their human counterparts. Multiple deletions and duplications seem to have happened in both genes during hominoid evolution; the chimpanzee had deleted the entire C epsilon 2 gene after its divergence. In addition, the length of the C alpha 1 hinge region of gorilla is distinct from those of chimpanzee and humans. Structural homology of the epsilon and alpha genes suggests that humans are evolutionarily closer to chimpanzees than to gorillas.

Animals↗
PubMed1988

Human immunoglobulin D segments: isolation of a new D segment and polymorphic deletion of the D1 segment.

We have isolated and identified a new human germline D segment which is not physically linked to the known D cluster. The nucleotide sequence of the new D segment was highly homologous with the known D segments. Frequent polymorphic deletion of the D1 segment was found in the Japanese population. Nucleotide sequences surrounding the deletion indicate that homologous recombination is likely to be responsible for the deletion of the D1 segment.

Amino Acid Sequence↗
PubMed1988

Effect of human recombinant interleukin 5 and G-CSF on eosinophil colony formation.

Human recombinant (r) IL-5 was shown to have the activity to stimulate eosinophil (Eo) colony formation from human non-T, non-adherent bone marrow cells. The majority of these colonies were found to contain a small number of basophils, macrophages or neutrophils. Human rG-CSF, which alone did not stimulate Eo colony formation, showed an enhancing effect on Eo colony formation when added with IL-5. IL-5 seems to stimulate the proliferation and differentiation of CFU-Eo, while G-CSF acts on the early stage of eosinophilopoiesis.

Cell Differentiation↗
PubMed1988

A unique monoclonal antibody derived from a lupus-prone mouse with multiple bindings to autoantigens associated with rheumatic disease.

Monoclonal anti-poly(ADP-ribose) (MRP-2) was primarily a product of a hybridoma selected by binding to poly(ADP-ribose) from an autoimmune MRL/Mp-lpr/lpr (MRL/1) mouse. Detailed examination revealed that anti-poly(ADP-ribose) monoclonal IgMK antibody bound not only to left-handed Z-DNA and single-stranded (ss) DNA but also to a conformational epitope formed by histone and double-stranded (ds) DNA. A reconstitution study revealed that association of dsDNA with histone H3 plus H4 was essential for their binding to MRP-2 monoclonal antibody. MRP-2 monoclonal antibody acted as a rheumatoid factor (RF). Since some monoclonal or polyclonal human serum antibodies of rheumatoid arthritis (RA) or mixed connective tissue disease (MCTD) have been reported to recognize shared epitopes of denatured IgG and DNA-histone (nucleosomes), this MRP-2 monoclonal antibody with the similar activity derived from a lupus-prone mouse will be useful for the studies on the etiology of autoantibodies associated with RA, MCTD and systemic lupus erythematosus (SLE).

Animals↗
PubMed1988

A soluble 'anchorminus' interleukin 2 receptor suppresses in vitro interleukin 2-mediated immune responses.

The immunosuppressive effects of a recombinant soluble IL-2 receptor L chain (s-IL-2R) were analyzed. S-IL-2R protein was obtained from the conditioned medium of L cells transfected with a mutant cDNA clone encoding the extracytoplasmic portion of the IL-2 receptor (IL-2R) and was purified to homogeneity by an IL-2-coupled sepharose column, following by reverse phase chromatography (HPLC). Soluble IL-2R protein thus prepared retained the ability to bind IL-2 specifically and suppressed the in vitro IL-2-mediated immune responses, including proliferation of IL-2-dependent cell line (CTLL-2), induction of secondary cytotoxic T lymphocytes (CTL) and the mixed lymphocyte reaction (MLR), but did not suppress the growth of IL-3-dependent cell line. Kinetic studies revealed that s-IL-2R exhibited the suppressive effects on the proliferative responses of alloantigen stimulated human tonsillar cells, only when added at an early stage, namely 0-48 h after culture onset, whereas cyclosporin A (CsA) exhibited an inhibitory effect only when added at between 0 and 24 h. This implies that s-IL-2R exerts its effect on an early stage of lymphocyte activation. The observed immunosuppressive effects of s-IL-2R suggest the possibility that s-IL-2R might be useful for the protection of rejection crisis in organ transplantation.

Animals↗
PubMed1988

Application of a human T cell line derived from a Sézary syndrome patient for human interleukin 4 assay.

Interleukin 4 (IL-4) is a multi-functional biological regulator molecule. We developed a simple assay system for human IL-4, using a IL-2-dependent T cell line designated Sez 627 cell line. Sez 627 cells were found to respond only to human IL-4 and human IL-2, but not to other available lymphokines. In combination with mouse IL-2-dependent CTLL-2 cell line, which responds to both human and murine IL-2 but not to human IL-4, human IL-4 activity can be discriminated from human IL-2 activity.

Biological Assay↗
PubMed1988

Loss of alleles at loci on chromosome 13 in human primary gastric cancers.

Mitotic events leading to the loss of the normal allele corresponding to a mutated gene are important for tumorigenesis in rare heritable tumors such as retinoblastoma and Wilms tumor. As reported for both colorectal and breast cancers, some common tumors seem to develop because of the same mitotic events. We examined constitutional and tumor genotypes defined by polymorphic DNA clones in 36 patients with gastric cancer. In 14 cases, constitutional heterozygosity at loci on chromosome 13 had been lost. Loss of alleles was also detected at a locus on chromosome 18 in two cases and at a locus on chromosome 17 in one case. The frequent loss of alleles at loci on chromosome 13 (41%) suggests that elimination of genes on this chromosome may be of importance in the tumorigenesis of human primary gastric cancers.

Alleles↗
PubMed1988

Differentiation of an interleukin 3-dependent precursor B-cell clone into immunoglobulin-producing cells in vitro.

Precursors to B-cell lines with immunoglobulin genes in the germ-line context have been shown to be capable of generating mature B cells in vivo. We report here that an interleukin 3-dependent precursor B-cell line, LyD9, differentiated in vitro into mature B cells, producing IgM and IgG by coculture with bone marrow accessory (or stroma) cells or with dendritic cells and T cells. Up to 50% of IgM-positive cells, but no Thy-1-positive cells, appeared after the 7- to 10-day coculture. Induced LyD9 cells underwent heterogenous immunoglobulin gene rearrangement and synthesized mRNAs encoding immunoglobulin mu, gamma, and kappa chains. However, these cells did not show any rearrangement of genes encoding the alpha and beta chains of the T-cell receptor. The induction of differentiation by coculture with bone marrow stroma cells was blocked by anti-lymphocyte function-associated antigen 1 or anti-interleukin 4 antibody. These systems are useful for molecular biological studies on regulation of differentiation of bone marrow-derived cells into the B-cell lineage.

Animals↗
PubMed1988

Biased expression of variable region gene families of the immunoglobulin heavy chain in autoimmune-prone mice.

We have examined usage of variable region gene families of the immunoglobulin heavy chain (VH gene family) in spleens of MRL/MpJ-1pr/lpr (MRL/lpr), (NZB x NZW)F1, and BXSB mice by Northern analysis using various VH probes, including the VHPAR gene which we cloned and identified as a gene encoding the heavy-chain variable region of antipoly(ADP-ribose) antibody. The amount of VHS107 family mRNA was almost constant for the same amount of splenic crude RNA in autoimmune-prone and normal mice, while concentrations of other family mRNAs were elevated in autoimmune-prone mice. For example, per splenic RNA the VHPAR family was expressed in MRL/lpr mice 10 times more than in their normal counterpart, MRL/MpJ-+/+ (MRL/+) mice. These results indicate the bias of VH gene usage in autoimmune-prone mice. Expression of the VHS107 family was depressed from an early life stage of MRL/lpr and male BXSB mice. Furthermore, the expression of IL-4 and IL-5 were quantitatively compared, as B cell differentiation factor was thought to be produced by abnormally proliferative T cells in lymph nodes of MRL/lpr mice. We could not, however, observe overproduction of IL-4 and IL-5 mRNA in the lymph nodes.

Amino Acid Sequence↗
PubMed1988

Immunogenotypes of lymphoid malignancies; the rearrangement of T cell receptor beta chain gene can occur before the gamma chain gene rearrangement.

Immunoglobulin (Ig) and T cell receptor (TcR) gene rearrangements were analyzed in 101 cases of lymphoid malignancies in association with a surface phenotype study. In leukemias/lymphomas with mature phenotype, there is a good correlation between phenotypes and genotypes. However, in leukemias/lymphomas with immature phenotype, we found many discordances between phenotypes and genotypes, suggesting the stochastic nature of hematopoietic cell differentiation at the early stage. As for TcR beta and gamma chains, the rearrangement of gamma chain gene is considered to occur slightly prior to that of beta chain gene. However, we observed a mature T cell malignancy, adult T-cell leukemia, with rearranged beta chain gene and germ line gamma chain gene, showing the possible existence of another pathway of T cell differentiation.

Cell Differentiation↗
PubMed1988

Occurrence of respiratory syncytial virus subgroup A and B strains in Japan, 1980 to 1987.

The subgroup characteristics of 71 strains of respiratory syncytial virus (RSV) isolated in Sapporo, Japan, during 5 epidemic years from 1980 to 1987 were determined by the use of 17 monoclonal antibodies (MAbs) raised against the RSV Long strain, which is now recognized as the prototype subgroup A strain. Nine of these MAbs immunoprecipitated the fusion protein (F), five immunoprecipitated the large glycoprotein (G), two immunoprecipitated the nucleoprotein (NP), and one immunoprecipitated the phosphoprotein (P). Based on the pattern of reaction of these MAbs to RSV isolates in an indirect immunofluorescence assay, we were able to distinguish two different subgroups. Subgroup A strains reacted to all 17 MAbs. Subgroup B strains reacted to none of the anti-G MAbs, eight of the nine anti-F MAbs, and all anti-NP and anti-P MAbs. Subgroup A included 38 (53.5%) isolates from every epidemic year. Subgroup B included 32 (45.1%) strains isolated in the last 4 epidemic years. One virus strain with an intermediate character of reactivity was isolated in 1983. From the first epidemic year, six subgroup A strains and no B strains were isolated. During the next three annual epidemics, subgroup B strains were predominantly isolated, i.e., 8 of 13, 10 of 13, and 13 of 17 strains. However, in the last epidemic year only one strain of 22 isolates belonged to subgroup B, and the remainder belonged to subgroup A. This variability of dominance in the occurrence of different RSV subgroup strains may suggest a possible role of the subgroup-specific immune response in RSV epidemics.

Antibodies, Monoclonal↗