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T Tada

Publications and source records attributed to T Tada.

At least 451 records · Page 25Linked to original sources
PubMed1974

Selective roles of thymus-derived lymphocytes in the antibody response. I. Differential suppressive effect of carrier-primed T cells on hapten-specific IgM and IgG antibody responses.

Passively transferred thymocytes and spleen cells from donors primed with keyhole limpet hemocyanin (KLH) exerted differential suppressive effect on IgM and IgG antibody responses of syngeneic recipients immunized with DNP-KLH depending primarily on the time when KLH-primed cells were transferred. This was demonstrated by the decrease in the numbers of DNP-specific direct and indirect PFC in the spleen of the recipients given KLH-primed cells at different times during primary and secondary immunization. Whereas the cell transfer simultaneously with or 2 days after the primary immunization produced only slight suppression of the peak IgM antibody response, it caused profound suppression of late IgM and IgG antibody responses. By contrast, the cell transfer 3 days after the immunization produced immediate suppression of the ongoing IgM antibody response resulting in its earlier termination, while being unable to prevent the induction of IgG antibody response. KLH-primed cells could moderately suppress the secondary anti-DNP antibody response, in which IgG antibody response was found to be slightly more sensitive than IgM antibody response to the suppressive influence of KLH-primed cells. The suppressive effect of the KLH-primed spleen cells was completely eliminated by the in vitro treatment of the cells with anti-theta and C before cell transfer, indicating that cells responsible for the suppression are, in fact, T cells. The suppression of DNP-specific antibody response by KLH-primed T cells was achieved only if the recipients were immunized with DNP-KLH but not with DNP-heterologous carrier, suggesting that direct interaction between T and B cells is necessary for the suppression of the antibody response. It is concluded that susceptibility of B cells to the specific suppressive influence of T cells is inherently different depending on the differentiation stage of B cells and on the immunoglobulin class they are destined to produce.

Animals↗
PubMed1974

Selective roles of thymus-derived lymphocytes in the antibody response. II. Preferential suppression of high-affinity antibody-forming cells by carrier-primed suppressor T cells.

Passive transfer of thymocytes and spleen cells from donors primed with keyhole limpet hemocyanin (KLH) caused significant decrease in the average avidity of anti-DNP antibodies produced by direct and indirect PFC in the recipients in both primary and adoptive secondary antibody responses against DNP-KLH. The analysis of the avidity distribution of antibodies produced by plaque-forming cells (PFC) indicated that the observed decrease in the average avidity is primarily due to the selective loss of high avidity subpopulation of PFC leaving low avidity subpopulation relatively unaffected. The degree of suppression in antibody avidity did not correlate with the reduction in the number of PFC, and thus causing the "shift" of avidity distribution of PFC to the low avidity end. These results indicate that the "maturation" of antibody in the T-cell-dependent antibody response is influenced by the carrier-specific suppressor T cells with respect to the emergence and selection of B cells having high affinity receptors for hapten. It is suggested that B cells binding antigen with high affinity receptors would be more easily affected than those with low affinity receptors by specific suppressor T cells which are capable of reacting the carrier portion of the same antigen.

Aminocaproates↗
PubMed1974

Dual regulatory role of the thymus in the maturation of immune response in the rabbit.

Rabbits thymectomized in early adulthood produced more antihapten antibody than sham-thymectomized controls after hyperimmunization with 2,4-dinitrophenyl bovine gamma globulin (DNP-BGG). The average associated constant of anti-DNP antibody produced by thymectomized animals was more than 10 times higher than that of the controls. Similar effects were obtained by extensive treatment of rabbits with antithymocyte serum (ATS) before and during the immunization with DNP-BGG. The results indicated that relative diminution of thymus-derived lymphocytes (T cells) resulted in a stimulation of antibody-forming cells with a higher affinity. On the other hand, preimmunization of rabbits with different doses of BGG caused either enhancement or suppression of the hapten-specific antibody response, depending on the priming dose of BGG. The suppressed antibody response was always associated with a marked decrease in the antibody affinity. If rabbits were partially tolerized with a large dose of soluble BGG, some of the animals produced little antibody against hapten (DNP) coupled to this carrier, and the affinity of produced antibody was low. However, other rabbits tolerized with BGG produced large amounts of anti-DNP antibody upon hyperimmunization with DNP-BGG, whose affinity was only slightly lower than that of the control. These results can be harmonized if it is assumed that the thymus plays an important role in the maturation of the immune response. It is postulated that T cells, in numbers ordinarily available, would first assist in the proliferation of antihapten antibody-forming cell precursors already selected by antigen, thus accounting for the rapid increase of antibody affinity in the early stage of immunization. However, after a larger number of carrier-specific T cells are made in response to continued immunization, these would suppress antibody-forming cells. The suppression would be greater for cells with higher affinity for antigen, resulting in a decrease in antibody affinity. This postulate explains preferential stimulation and suppression of cells having higher affinity receptors under circumstances in which T cell are relatively depleted or overstimulated, and further permits an explanation for the decrease of antibody affinity after long-term immunization.

Animals↗
PubMed1972

Clinical, microbiological, and immunological studies in patients with immunoglobulin deficiencies and gastrointestinal disorders.

Seven patients with gastrointestinal disorders and deficiencies of serum and secretory immunoglobulins were evaluated clinically, microbiologically, and immunologically. Five patients had generalized deficiencies of immunoglobulins; two were selectively deficient. Diarrhoea and malabsorption in six of the seven patients were at least partially explained. Four of the five patients with generalized hypogammaglobulinaemia had intestinal infestation with Giardia lamblia; in three of the five, excessive numbers of anaerobic bacteria were cultured from small bowel fluids. Despite much variability in relative severity of patients' respiratory and gastrointestinal tract symptoms, deficiencies of mucosal immunocytes and immunoglobulins in nasopharyngeal and gastrointestinal tract tissues and secretions were similar. Except for one selectively IgA-deficient patient, all patients were deficient in IgE. The study characterizes in greater detail than heretofore the gastrointestinal disorders associated with immunoglobulin deficiency states.

Adolescent↗