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Biomedical subjects

T Han

Publications and source records attributed to T Han.

At least 217 records · Page 12Linked to original sources
PubMed1976

Adjuvant immunotherapy in bronchogenic carcinoma.

Ten patients with locally far advanced bronchogenic carcinoma were treated with autologous tumor vaccine after a radical surgical resection. Three of 10 patients treated with tumor vaccine are alive (median survival of 26 months) whereas all nine patients in the control group are dead (median survival of 6.5 months). Active immunotherapy adjunct to radical surgery appeared to improve cellular immunity of the treated patients in the postoperative period, and the migration inhibition test indicated sensitization of treated patients against their tumor.

Antigens, Neoplasm↗
PubMed1976

Human thymus cells. Excellent responders but poor stimulators in 'One Way' mixed lymphocyte reaction.

Human allogeneic 'one-way' mixed lymphocyte reactions between thymus cells and thymus cells were entirely absent. Of twenty-one mixed lymphocyte reactions between peripheral blood lymphocytes as responding cells and thymus cells as stimulating cells, only eleven had a weak but significant reaction. In contrast, a highly significant response was observed in each of eighteen mixed lymphocyte reactions between thymus cells as responding cells and peripheral blood lymphocytes as stimulating cells and in each of eleven mixed lymphocyte reactions between peripheral blood lymphocytes and peripheral blood lymphocytes. These findings indicate that the thymus cells (T lymphocytes) possess excellent proliferative capacity, with little or no stimulating capacity, while peripheral blood lymphocytes (T and B lymphocytes), on the other hand, are good responders, as well as good stimulators, in the mixed lymphocyte reaction.

Antibodies↗
PubMed1976

Enhancement of "one-way" human mixed lymphocyte reaction by cholinergic agents.

"One-way" mixed lymphocyte reaction was not enhanced when the cells were allowed to be exposed to acetylcholine or carbamylcholine at a concentration of 0.01-1.0mumole/ml during the entire period of culture. It was thought to be due to cytotoxicity effect of these agents on responding cells. When the responding cells were incubated with cholinergic agents for 1 hr prior to washing the cells and setting up the mixed cell culture, "one-way" mixed lymphocyte reaction was enhanced. However, when the stimulating cells were similarly treated with either agent, no enhancement of "one-way" mixed lymphocyte reaction was observed. These observations indicate that cholinergic agent induces enhancement of mixed lymphocyte reaction by affecting only the responding cells and not the stimulating cells.

Acetylcholine↗
PubMed1976

Human thymus cells: blastogenic response to mitogens, antigens and allogeneic cells.

Over 90 per cent of the thymus cells from each of twenty-six donors were T lymphocytes, identified by E-rosetting and less than 3 per cent of the cells were B lymphocytes identified by EAC-rosetting. With advancing age, the proportion of T lymphocytes decreased while that of B lymphocytes increased. The degree of (3H)thymidine incorporation of thymus cells was inversely proportional to the age of the thymus-cell donor. The PHA or PWM- induced blastogenic response of thymus cells gradually increased with advancing age when the response was expressed as the stimulation index. However, the actual rate of (3H)thymidine incorporation in all three groups was rather similar when cells were cultured with mitogens. The difference in stimulation index was due to the variation in incorporation rate in cultures without stimulants. The PHA response was approximately four-fold higher than that of PWM response. Thymus cell response to allogeneic lyphocytes, on the other hand, had no correlation with the age of thymus donor. The most surprising result in the present study was that the thymus cells from each of ten donors, aged 1-14 years, were incapable of responding to all four different recall antigens. Peripheral blood lymphocytes from nine to ten randomly selected age-matched children responded very well to one or more antigens.

Adolescent↗
PubMed1976

T and B lymphocytes. Exclusive role as responders and stimulators in human one-way mixed lymphocyte reaction.

Four different combinations of one-way mixed lymphocyte reactions between human peripheral blood T and B lymphocytes (at a ratio of 1:1), purified by the E-rosetting technique, were carried our. A significant mixed lymphocyte reaction was observed only in a combination in which T lymphocytes, as responding cells, and B lymphocytes, as stimulating cells, were utilized. No significant mixed lymphocyte reaction was noted in the other three combinations of cells, using T or B lymphocytes as responders and T lymphocytes as stimulators, and also B lymphocytes as both responders and stimulators. Mixed lymphocyte reactions between T lymphocytes as responders (at constant concentration) and T and B lymphocytes as stimulators (varying proportions) showed that the response decreased proportionately with decreasing numbers of B cells and increasing numbers of T cells used as stimulators. Addition of increasing numbers of stimulating T cells to a constant number of stimulating B cells did not suppress or enhance the T-cell response to B cells. These observations indicate that the human peripheral blood T and B lymphocytes play an exclusive role as responding cells and stimulating cells, respectively.

B-Lymphocytes↗
PubMed1976

Whole blood microculture assay of human lymphocyte function.

A whole blood microculture assay is described for measuring lymphocyte reactivity to mitogenic and antigenic stimulants. This assay employs heparinized whole blood, serum-free culture medium, microtiter plates, and a Multiple Automated Sample Harvester (MASH). When this assay is compared to other leukocyte assays, its major advantages include (1) the utilization of fewer lymphocytes per microculture, thuus reducing the amount of blood required per test while increasing the number of test agents and replicate cultures which can be employed in any given experiment; (2) the conservation of mitogens, antigens, drugs, enzymes, hormones, lymphokines, and other test agents, some of which are either expensive of difficult to prepare in large quantities; (3) the elimination of lymphocyte isolation and purification procedures which may disrupt the relative proportion of T cells, B cells and antigen-processing cells; and (4) the application of an automated harvester which simplifies and expedites procedures required for processing cells for liquid scintillation counting.

Cell Separation↗
PubMed1975

Disparity in the production of lymphoblastogenesis inhibition factor by cultured human B and T lymphoid cell lines.

A comparative study of inhibitory effects of cell-free supernatants from cultured human B and T lymphoid cell lines on lymphocyte blastogenesis indicated that the inhibitory effect of supernatant from B lymphoid cells on lymphocyte blastogenesis was significantly higher than that of supernatant from T lymphoid cells or from non-lymphoid neoplastic cells. The inhibitory effect of supernatant was reversible and dose-related. The inhibitory effect gradually diminished with time when the supernatant from B lymphoid cells was added to the culture, 1-3 days after the beginning of cultures. The supernatant of human B lymphoid cells was also found to be highly active in affecting the mouse thymus cell response. The biological nature of this inhibitory factor has not been defined. Both B lymphoid cell lines used in the present study contained Epstein-Barr virus (EBV) genomes while the T-cell line and the non-lymphoid neoplastic cell lines were free of EBV genomes. Sensitivity of the supernatant of B lymphoid cells to u.v. irradiation and heat suggests the possibility that the EBV genomes released into the culture medium may be responsible for inhibition of lymphocyte blastogenesis; resistance of this supernatant to DNase suggests that the EBV genomes may be double-stranded DNA.

Animals↗
PubMed1975

Adoptive transfer of cell-mediated immunity to tuberculin using RNA from tuberculin-sensitive subjects.

Adoptive transfer of delayed hypersensitivity skin test response to tuberculin with 'immune' RNA extracted from the sensitized lymphocytes of a healthy subject or a patient with Hodgkin's disease was successfully demonstrated in previously non-sensitive patients with neoplastic diseases including Hodgkin's disease. 'Non-immune' RNA obtained from non-sensitive man, on the other hand, failed to transfer PPD skin reactivity in non-sensitive recipients. 'Immune' RNA-mediated PPD skin test response remained positive for a considerable period of time, indicating that the effect of 'immune' RNA is systemically active. 'Immune' RNA was found to be RNase-sensitive but DNase-resistant. In vitro adoptive transfer of delayed hypersensitivity with 'immune' RNA, as assayed by lymphocyte transformation test, was unsuccessful.

Deoxyribonucleases↗
PubMed1975

Human chorionic gonadotropin. Its inhibitory effect on cell-mediated immunity in vivo and in vitro.

An inhibitory effect of human chorionic gonadotropin (HCG) on delayed hypersensitivity skin test responses in guinea-pigs given 4000 i.u. of HCG intraperitoneally, 1--7 days prior to skin testing, is presented. The effect of HCG on skin test responses lasted for at least 3 weeks. Inhibition of lymphocyte response to PHA or PPD in the HCG-treated guinea-pigs was also observed. Guinea-pig peripheral blood lymphocyte response to mitogen or antigen is unequivocally inhibited by HCG in vitro. The effect of this hormone is not due to direct cytotoxicity, and its inhibitory effect seems to be dose related. These observations support the hypothesis that the HCG and possibly other placental hormones might play an important role in protecting the foetus against maternal rejection.

Animals↗
PubMed1975

Specific effect of neuraminidase on blastogenic response of sensitized lymphocytes.

The blastogenic response of sensitized lymphocytes from guinea-pigs to 'de novo' antigens (KLH, HCH and PPD) was ehhanced by BCN treatment in twenty-one of twenty-three instances. In contrast, no effect of VCN on nonsensitized guinea-pig lymphocyte response to these antigens, or to mumps antigen, was noted in any of thirty-four instances, These findings indicate that the enhancement effect of VCN is specific for sensitized lymphocytes. Heating VCN at 100 degrees for 10 minutes completely abolished the enhancement effect on the lymphocyte response. VCN treatment did not change the kinetics of antigen-induced blastogenesis. The increased lymphocyte response could probably be related to unmasking of the antigen receptor sites of the cells, resulting in increased antigen uptake, following the VCN treatment.

Animals↗
PubMed1975

In vitro transfer of tumour-specific immunity with human 'immune' RNA.

In vitro tumour-specific immunity against lung cancer was passively transferred in the leucocyte migration inhibition system with 'immune' RNA in man; 'non-immune' RNA, on the other hand, failed to transfer such immunity, indicating the specificity of 'immune' RNA.

Antigens, Neoplasm↗
PubMed1975

Disparity of mixed lymphocyte reactivity to cultured cells of human T and B lymphoid lines.

Repeated attempts with difference assays and experimental conditions failed to detect significant peripheral blood lymphocyte reactivity in one-way mixed lymphocyte reactions to irradiated or mitomycin C-treated cells of the "leukemic" T lymphoid line RPMI 8402. In contrast, consistently high levels of peripheral blood lymphocyte reactivity were obtained with cells of six B lymphoid lines established from the same blood sample used to initiate this T lymphoid line. Although attempts to define the reason why these cultured T cells did not initiate a mixed lymphocyte reaction were not successful, evidence indicates that this inability may be an intrinsic characteristic common to three other T lymphoid lines (MOLT-4, CCRF-CEM, and CCRF-HSB-2), also established from patients with relapsed acute lymphoblastic leukemia.

B-Lymphocytes↗