Takako Nakatsuji

Association of HLA-A24 With Complete β-Cell Destruction in IDDM

A sensitive C-peptide immunoreactivity radioimmunoassay demonstrated the presence of subtle, but definite residual β-cell function in patients with IDDM of long duration. Although HLA antigens are known to influence susceptibility to IDDM, their contribution to the extent of pancreatic β-cell destruction has not yet been examined extensively. We studied the relationship between residual β-cell function and HLA class I and class II antigens in 111 unrelated Japanese IDDM patients. Using the sensitive C-peptide immunoreactivity radioimmunoassay, the presence or absence of residual β-cell function was evaluated by the C-peptide immunoreactivity response to a 100-g oral glucose load. DNA typing for HLA-DQA1 and HLA-DQB1 antigens was performed in addition to serological typing of HLA-A, HLA-B, HLA-C, and HLA-DR antigens. A C-peptide immunoreactivity response > 0.033 nM was regarded as an indication of the presence of residual β-cell function, not the assay error. Surprisingly, 35 of 37 (94.6%) patients without residual β-cell function had HLA-A24, whereas only 39 of 74 (52.7%) patients with residual β-cell function had this antigen (corrected P = 9.795 × 10(–6). Any other HLA antigens, including the DR and DQ loci, showed no difference in the frequency with regard to residual β-cell function. The duration of diabetes was similar between the groups with and without residual β-cell function. The duration of diabetes was similar between the groups with and without residual β-cell function. Even when the patients were stratified according to the duration of diabetes, HLA-A24 was more common in those with early complete loss of β-cell function (duration of diabetes <1 yr) (P = 0.035) and was less common in those with residual β-cell function despite a long duration of diabetes (>10 yr) (P = 0.001). The correlation between HLA-A24 positivity and complete β-cell loss also was confirmed in younger-onset (<30 yr old) and elder-onset (≥30 yr old) groups. The C-peptide immunoreactivity response in patients with HLA-A24 (0.09 ± 0.02 nM, mean ± SE, n = 74) was significantly lower than that in patients without HLA-A24 (0.19 ± 0.03 nM, n = 37, P < 5.0 × 10−5). Further typing of HLA-A24 by one-dimensional isoelectric focusing gel electrophoresis revealed that the isoelectric point of HLA-A24 was identical in charge in 17 of 18 patients and 7 normal control subjects (isoeletric point 6.32, HLA-A24.1). We conclude that a specific HLA class I antigen, HLA-A24, promotes pancreatic p-cell destruction in IDDM patients with other disease-susceptible HLA antigens.

Stages of Embryonic Development of the Ice Goby (Shiro-uo), Leucopsarion petersii

Abstract A series of normal stages for the embryonic development of the ice goby (shiro-uo), Leucopsarion petersii, which belongs to the Perciformes, is described. Stages are based on morphological features, by utilizing the optical transparency of live embryos from the first cleavage to the hatching stage. Fertilized eggs were obtained by artificial insemination and normal embryogenesis was accomplished in a defined medium in plastic petri dishes at 19°C. Shiro-uo eggs were surrounded by a very thin and clear chorion and could be dechorionated with forceps very easily. Developmental stages were mostly comparable to those of other fish embryos described so far, but several differences were indicated, such as the third cleavage plane being horizontal, and that the length of the cleavage cycle increased gradually from the very early stages. Also, there were differences in the relative rates of organogenesis of the brain, eyes, otic vesicles, and somites when compared to the zebrafish and medaka.

Importance of DQB as an indicator in living-related kidney transplant

Southern blot hybridization was performed in 16 pairs of living-related kidney transplant patients and donors, using DNA samples extracted from peripheral blood lymphocytes. The number of HLA-DNA-mismatched bands was used as an indicator for graft survival. The total number of DNA-mismatched bands seemed to be a valuable parameter. This was further analyzed and it was found that DQB in particular could be used to predict graft survival. Especially, usefulness of HLA-DNA typing was found in positive MLR, where good prognosis was strongly related to DQB matching. This method can therefore be applied in selecting a suitable living-related donor with the best chance of graft survival.

The Role of Transfected HLA-DQ Genes in the Mixed Lymphocyte Reaction-Like Condition

DR gene products are commonly thought to be involved in the induction of the mixed lymphocyte reaction (MLR). However, very little is known about the role of HLA DQ antigens in the MLR. To address this question, we introduced DQα andβ chain genes into mouse L cells, a human T -cell line, and a human premonocytoid cell line using a liposome-mediated transfer technique. The DQα and DQβ genomic clones were isolated from a DR2 DQw1 and a DR3 DQw2 phage library, respectively. ThepSV2-Neo gene was introduced as a selection marker with both DQα and DQβ. The resultant transfected cells were able to bind several HLA class II monoclonal antibodies. In addition, these cells were found to be efficient in stimulating peripheral blood lymphocyte proliferation under MLR-like conditions, implying a role for HLA-DQ molecules in HLA-D typing differences.

Germ Cell Lineage from a Single Blastomere at 8-Cell Stage in Shiro-uo (ice goby)

Abstract Shiro-uo (ice goby; teleost fish), Leucopsarion petersii, shows a unique cleavage pattern characterized by two tires of blastomeres at 8-cell stage, like that of echinoderm and amphibian embryo. Such a pattern is suitable to isolation and cell lineage experiments. In this study, cell lineage of germ-line was traced by histological observation and cell labelling experiment at the 8-cell stage. Primordial germ cells (PGCs) were first detected histologically at the 10-somite stage, and migrated to gonadal anlage at 10 days post-fertilization, through usual way described in other teleost species. When a single blastomere was labelled with tracer dye at 8-cell stage, both upper and lower tires generated labelled PGCs at gonadal anlage although upper tires occasionally. This result suggests that all blastomeres at the 8-cell stage have potential to produce PGCs in shiro-uo.

HLA-DQ structural polymorphism in HLA-DR2 associated HLA-D clusters

Three homozygous cell lines with different cellular HLA-D specificities associated with HLA-DR2 including Dw2, Dw12, DB9 displayed structural variation in the products of the DQ locus. Nonglycosylated precursor polypeptides of DQ molecules immunoprecipitated by two-dimensional polyacrylamide gel electrophoresis (2-D gel) revealed distinct differences in the patterns of DQ alpha and DQ beta chains.

Proliferative Response by Stimulation of DP-Transfectants

DP antigens are products of the HLA-D region (class II antigens) along with DR and DQ. They were first defined by the primed lymphocyte typing (PLT) system (1–3). Whereas alloantisera exist against DR and DQ, no single DP specific alloantiserum has yet been discovered (4). The role of HLA-DP in transplantation immunology has not been defined. By introducing DP gene clones into cell lines, the resultant transfectant cells will allow the expression of DP antigens and hence enable their study. Using such transfectant cells as stimulator cells, the T-cell proliferative response was measured. In this study, it was observed that DP transfectant cells could generate a T-cell response.

PLT Analysis of D Region Complexity by Cloned Cells: A New Non-DP Antigen

The HLA-D region is very complex. HLA-D specificity is not identical to DR. It is not known whether the difference in HLA-D of cells with the same DR can be supposed to be due to one antigen determinant. To resolve the problem, PLT clones were used. From the MLC of cells with the same DR, DQ, DP antigens but with different D antigens, Dwl5-specific PLT clones and a Dw4-specific clone were established.