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Biomedical subjects

T Morito

Publications and source records attributed to T Morito.

67 records · Page 4Linked to original sources
PubMed1979

Studies of human cord blood and adult lymphocyte interactions with in vitro immunoglobulin production.

Newborns are unable to produce normal amounts of immunoglobulin despite the presence of circulating lymphocytes with surface immunoglobin (Ig). This study was designed to examine the cellular basis of such impaired Ig synthesis in the newborn infant. An in vitro assay for IgG and IgM synthesis was employed which measured the Ig present in the supernates of pokeweed mitogen-stimulated cord blood and/or adult peripheral mononuclear cells (MNC). Results were as follows: (a) the addition of cord blood MNC to adult MNC suppressed both normal IgG and IgM production; (b) addition of a suspension of adult thymus-derived (T) cells to cord bone marrow-derived (B) cells did not enhance the production of Ig; (c) the addition of cord T cells to adult B cells did not enhance normal Ig production but did significantly depress IgM and IgG synthesis; and (d) irradiation of cord T cells with 2,000 rads removed the suppressive effect of cord T cells on adult MNC. A similar reversal of the suppressive effect exerted by cord MNC was also seen in the presence of 10 microM of hydrocortisone. It appears that the inability of newborn infants to make normal amounts of Ig is a result of a combined B-cell defect and the presence of a steroid-sensitive and radiosensitive suppressor cord T cell.

Adult↗
PubMed1978

Fc-rosette inhibition by pregnant women's sera and by rabbit anti-beta2-microglobulin.

Some anti-HLA sera showed Fc-rosette inhibitory activity, which had little correlation with type-specific anti-HLA activity. Cytotoxic titers did not correlate with Fc-rosette inhibition rate and these antisera showed considerable inhibition of rosette formation even after absorption of anti-HLA activity with T lymphocytes. These results suggest that some anti-HLA sera contain B-cell-specific inhibitory activity against Fc-receptor like anti-Ia antibody in mice. Rabbit antiserum against human beta2-microglobulin showed specific inhibition of Fc-rosette formation. It was suggested that Fc-receptor or Ia-like antigen in human has a close relation with beta2-microglobulin.

Animals↗
PubMed1978

Close association of human mixed lymphocyte culture antigen, Ia-like antigen and Fc receptor.

The effects of aggregated human IgG, human anti-Ia-like antibody, and anti-beta2-microglobulin on mixed lymphocyte culture (MLC) were studied. Aggregated human IgG inhibited both stimulatory and responding activities in MLC. When Fc-receptor-bearing cells were removed from responding cells, the inhibitory activity of aggregated IgG was markedly reduced. The result suggested that the inhibition of MLC by aggregated IgG is primarily based on the blocking of Fc-receptor-bearing cells contained in the stimulator cells. In addition, the removal of Fc-receptor-bearing cells from stimulatory cells resulted in the loss of MLC response. Anti-Ia-like antibodies contained in anti-HLA sera and B-cell-specific human alloantisera also inhibited stimulatory activities in MLC. Rabbit antiserum against human beta2-microglobulin showed inhibitions of both stimulatory and responding activities. These results suggested the close association of human MLC stimulator site with Fc receptor and Ia-like antigen and also some relation of beta2-microglobulin with MLC reaction.

Antigens↗
PubMed1977

Inhibition of Fc-rosette formation by synovial fluids from patients with rheumatoid arthritis.

Human red cells sensitized with one of the Rh antisera (Ripley) form rosettes (Fc-rosette) with human B lymphocytes and the rosettes are well inhibited by aggregated human IgG. As synovial fluids from patients with rheumatoid arthritis are usually hypocomplementaemic and frequently contain immune complexes, they were used for the inhibition of Fc-rosette formations in this study. The Fc-rosette inhibitory rates were inversely correlated with the levels of CH50 and C4 in the synovial fluids. Fractionation studies of the synovial fluids by ultracentrifugation and Sephadex G200 gel filtration indicated that main inhibitory activities were present in macromolecular fractions. Reduction and alkylation of the synovial fluids resulted in marked reductions of inhibitory activities. The tested synovial fluids did not contain anti-HLA activity as assessed by the microcytotoxicity test. The Fc-rosette inhibitory rates were not correlated with the levels of C3 and immunoglobulins, nor with the activity of rheumatoid factors in the synovial fluids. These results indicate that the Fc-rosette formations are inhibited by the immune complexes contained in the synovial fluids and it was confirmed that the Fc-rosette inhibition test is a simple and sensitive method for the detection of circulating immune complexes.

Arthritis, Rheumatoid↗
PubMed1977

Reduced Fc-receptor bearing cells in peripheral bloods of patients with systemic lupus erythematosus and in rheumatoid synovial fluids.

Previous reports described that human red cells sensitized with one of Rh antisera (Ripley) make rosette formations (Fc-rosette with some lymphocytes. These Fc-rosettes were well inhibited by aggregated human IgG as well as hypocomplementemic systemic lupus erythematosus (SLE) sera and rheumatoid synovial fluids. In the present study, Fc-receptor bearing lymphocytes were considerably reduced in peripheral bloods of SLE (16.0 +/- 7.6%) and rheumatoid synovial fluids (15.6 +/- 5.3%). On the other hand, EAC-rosette formation rates of peripheral bloods of SLE (32.0 +/- 13.2%) and rheumatoid synovial fluids (30.3 +/- 11.2%) did not significantly differ from normal peripheral bloods (28.3 +/- 2.9%). E-rosette forming lymphocytes were reduced in peripheral bloods of SLE (48.7 +/- 15.7%) and in rheumatoid synovial fluids (49.0 +/- 14.6%) whereas 61.7 +/- 8.6% in normal peripheral bloods. Reduced Fc-rosette formation rates correlated well with the Fc-rosette inhibitory rates. In addition, eluates from the lymphocytes in rheumatoid synovial fluids also inhibited Fc-rosette formation. These results suggested that immune complexes present in peripheral bloods of SLE and rheumatoid synovial fluids are bound to the Fc-receptors on the lymphocytes, block the additional binding of the sensitized red cells, and result in the reduction of Fc-rosette formation.

Antigen-Antibody Complex↗
PubMed1975

Fc-rosette inhibition by hypocomplementaemic systemic lupus erythematosus sera.

Human red cells sensitized with one of the Rh antisera (Ripley) form rosettes (Fc-rosette) with human B lymphocytes and the rosettes are well inhibited by aggregated human IgG. Since sera of hypocomplementaemic patients with systemic lupus erythematosus (SLE) have frequently been reported to contain immune complexes, they were used for the inhibition of Fc-rosette formation in this study. The results of Fc-rosette inhibition rates of the sera were inversely correlated with the serum CH50 levels. When the sera were separated into top, middle, and bottom fractions by ultracentrifugation, the bottom fractions showed more effective inhititions than the others. Similarly, the strongest inhibition was found in the void volume of the serum separated by Sephadex G200 gel filtration. Reduction and alkylation of IgG resulted in the loss of reactivity with Fc receptor of B lymphocytes, and the rosette inhibiting activities of the SLE sera were markedly reduced after reduction and alkylation. Some of anti-HLA sera were inhibitory for the Fc-rosette formation, while the tested sera did not contain anti-HLA activity assessed by the microcytotoxicity test. These results indicated that circulating immune complexes contained in the sera inhibit the rosette formation, and that the Fc-rosette inhibition test is a simple and relatively sensitive method for the detection of circulating immune complexes. Antinuclear antibody activities of the sera were tested by the indirect immunofluorescent method; however, clear correlations were not obtained between Fc-rosette inhibition rates and staining patterns of antinuclear antibodies. On the other hand, the positive groups of LE-test exhibited slightly greater inhibition rates of the rosette than the negative groups.

Antibodies, Antinuclear↗