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Biomedical subjects

Y X Chen

Publications and source records attributed to Y X Chen.

87 records · Page 5Linked to original sources
PubMed1984

Characterization and expression of the HLA-DC antigens defined by anti-Leu 10.

The expression of HLA-DC antigens on peripheral blood mononuclear cells, in tonsil and lymph node tissue sections, on tumor cell lines, and on activated T cells was studied using monoclonal antibody, anti-Leu 10. Anti-Leu 10 reacts with HLA-DC molecules on homozygous B cell lines expressing HLA-DR 1,2,4,5,6,8, and 9. It reacts with heterozygous B lymphocytes expressing DR7 and DRw10, suggesting it also recognizes HLA-DC molecules linked to DRw10. The HLA-DC molecules detected by anti-Leu 10 are expressed on all Ig-positive and DR-positive peripheral B lymphocytes and an apparent subpopulation of DR-positive peripheral blood monocytes. Two-color immunofluorescence experiments using phycoerythrin-anti-HLA-DR (L243) and FITC-anti-Leu 10 demonstrated a correlation of the amounts of HLA-DR and DC antigens expressed on B lymphocytes. Cells expressing relatively low, or high amounts of one Class II molecule express respectively low or high amounts of the other Class II molecule. Anti-Leu 10 reacted with all B lymphocyte derived tumor cell lines not with lines of myeloid or erythroid origin, and with only one T cell derived line, HUT-78 which has an activated T cell phenotype. Consistent with this result, anti-Leu 10 binding suggested the presence of HLA-DC on activated T cells in lymphoid tissue, in addition to staining B cells. HLA-DC was also detected on mitogen and MLC activated T cells by anti-Leu 10 binding. Anti-Leu 10 is, therefore, a useful reagent for further studies of the role of HLA-DC in T cell activation and in normal B cell and monocyte functions.

Antibodies, Monoclonal↗
PubMed1984

Induction of T cell aggregation by antibody to a 16kd human leukocyte surface antigen.

We describe studies of a human leukocyte antigen, termed Leu-13, that is defined by a mouse monoclonal antibody that reacts with T and B lymphocytes. Optimal staining of T cells requires a much higher concentration of alpha Leu-13 (greater than or equal to 200 micrograms/ml) than alpha Leu-4 (6 micrograms/ml). However, the fluorescence intensity of T cells labeled with alpha Leu-13, washed and kept at 4 degrees C for different periods, does not diminish more rapidly than the fluorescence of T cells stained with alpha Leu-4 and treated the same way. These results indicate that the novel binding pattern of alpha Leu-13 is not due to weak affinity. Immunoprecipitation and SDS-PAGE analysis indicates that alpha Leu-13 precipitates a major 16-kilodalton (16kd) band and a minor 26kd component from Nonidet P-40-solubilized membrane of normal T cells that are surface-labeled with 125I. The similar sizes of the 16kd to 26kd (Leu-13) and 22kd to 28kd (Leu-4) molecules prompted us to compare the capacity of alpha Leu-13 and alpha Leu-4 to trigger T cell functions, and to co-modulate and co-precipitate the T cell antigen receptor. Unlike alpha Leu-4, alpha Leu-13 does not trigger T cell proliferation or augment NK activity, but inhibits the mitogenic effect of alpha Leu-4/T3 antibodies. alpha Leu-13 also induces T cells to clump into large aggregates after 16 hr of culture at 37 degrees C, but not at 4 degrees C. T cell aggregation is triggered by concentrations of alpha Leu-13 as low as 12.5 ng/ml. At this concentration, alpha Leu-13 is not detectable on the surface of T cells by indirect immunofluorescence analysis in a FACS. On leukemic T cells, alpha Leu-4 was found to co-modulate and co-precipitate a 38kd to 44kd dimer having apparent idiotypic determinants, whereas alpha Leu-13 did not. The possible significance of these findings to immune regulation by T cells is discussed.

Animals↗
PubMedDate not supplied

A neuromagnetic study of acupuncturing LI-4 (Hegu).

The brain magnetic fields evoked by acupuncturing LI-4(Hegu) were measured by using SQUID (superconductive Quantum Interference Device) Biomagnetometer, and the morphological characters of these biomagnetic fields were examined in 12 subjects. The observed phenomenon of the LI-4(Hegu)'s projection area overlapping on the jaw's and face's projection area suggests that excitation of LI-4 (Hegu)'s projection area activated by acupuncturing LI-4(Hegu) could inhibit action of the jaw's and face's projection through the overlapping area, and this is the reason why the acupuncturing LI-4(Hegu) could effectively case pains in the treatment of dental pain.

Acupuncture Points↗
PubMedDate not supplied

Preparation and characterization of monoclonal antibodies against sperm-specific lactate dehydrogenase C4.

LDH-C4, the testis-specific isozymes of lactate dehydrogenase (LDH), is the predominant LDH isozyme in mammalian spermatozoa. Nine monoclonal antibodies against mouse LDH-C4 have been developed. These antibodies were tested for cross reactivity with LDH-C4 from human testis and with LDH-1-5 from mouse and human testes by immunoelectrophoresis, bio-dot, and western blot assays. The results showed that all monoclonal antibodies were specific to LDH-C4 only: they did not react with LDH-1-5 from mice, nor from humans. The immunologic localization of the monoclonal antibodies on capacitated sperm was observed by indirect immunofluorescent assay. On mouse sperm the antibodies were bound to the tail only, but on human sperm eight antibodies were bound to the postacrosome, some to the neck and to the mid-piece. Most of the antibodies belonged to the Ig G class.

Animals↗