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Biomedical subjects

J Minowada

Publications and source records attributed to J Minowada.

At least 325 records · Page 18Linked to original sources
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

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↗
PubMed1975

Properties, inducibility, and an improved method of analysis of aryl hydrocarbon hydroxylase in cultured human lymphocytes.

The properties and inducibility of aryl hydrocarbon hydroxylase (AHH) in cultured human lymphocytes were studied, and a sensitive method of analysis has been developed. In agreement with other reports, peripheral blood lymphocytes per se had no activity and required pretreatment in culture with a mitogen for conversion to lymphoblasts to possess AHH activity. This activity had an absolute requirement for reduced nicotinamide adenine dinucleotide phosphate. Under our conditions of incubation, reduced nicotinamide adenine dinucleotide (1.3 mM) or ethylenediaminetetraacetic acid disodium salt (1 mM), when added to reduced nicotinamide adenine dinucleotide phosphate-fortified incubation mixture, caused about 30% increase in activity and MnCl2 caused an appreciable inhibition. The reaction was linear with the number of cells, with up to 16.8 X 10-6 cells contained in the incubation mixture, and had a pH optimum of 8.5. The enzyme was fairly stable at -70 degrees and retained about 90% of the original activity for 15 days. The enzyme activity in the mitogen-stimulated lymphocyte cultures appeared slowly and reached a maximum at 48 to 72 hr of incubation at 37 degrees, after which it considerably decayed with time. Viability of the cells in culture also decayed considerably after 72 hr and reached about 50% level at 120 hr. The enzyme was inducible with 3-methylcholanthrene and dibenz(a,h)anthracene. Dibenz(a,h)anthracene was a much more potent inducer than 3-methylcholanthrene and evoked a response in cells that would be considered noninducible with 3-methylcholanthrene. By using purified lymphocytes and Roswell Park Memorial Institute Medium 1640, providing larger surface area during culture, harvesting the cells at the time of minimum cell death and maximum AHH activity, and assaying AHH at its pH optimum of 8.5 instead of 7.6, it was possible to enhance the sensitivity of the assay an average of 17-fold.

Aryl Hydrocarbon Hydroxylases↗
PubMed1975

Antigenic determinants common to established human B-cell lines, but not shared by human T-cell lines (molt and sommer).

Rabbits were immunized with two kinds of human B-cell lines (SOMMER-B, and RPMI number 1788 cells) to get anti-B-cell sera. Sera were absorbed with human red blood cells, human liver, human brain and human T cells (MOLT-4 and SOMMER-T cells). Cytotoxicity of absorbed sera was not only tested against B cells which were used for immunization but also tested against unrelated B cells, including B35M cells derived from Burkitt lymphoma specimens. Results indicated that established human B cells had antigenic determinants which were shared with allogeneic human B cells, but not shared with non-lymphoid cells or tissues, nor with extablished human T cells.

Absorption↗
PubMed1974

Immunological functions of human T-lymphoid cell line (MOLT). I. Release of immunosuppressive factors from the mixture of MOLT-4 cells and sheep red blood cells.

A short term incubation of the mixture of established human T-lymphoid cells (MOLT) and sheep red blood cells (SRBC) resulted in the release of factors which nonspecifically suppressed the response of mouse spleen cells against heterologous erythrocytes in vitro. Neither human B-cell line (RPMI 1788), nor the supernate of MOLT cell suspension in the absence of SRBC had such suppressive effects. The supernate of the mixture of MOLT cells with chicken red blood cells (CRBC) did not suppress either anti-CRBC or anti-SRBC responses of mouse spleen cells. Since CRBC did not form rosettes with MOLT cells, it is suspected that the origin of the production of these factors might be MOLT cells forming SRBC rosettes. Some of these factors are dialysable.

Animals↗