Search PubMed⌕ Search

Biomedical subjects

J Yodoi

Publications and source records attributed to J Yodoi.

At least 289 records · Page 16Linked to original sources
PubMed1983

Failure of regulation of Tac antigen/TCGF receptor on adult T-cell leukemia cells by anti-Tac monoclonal antibody.

Anti-Tac monoclonal antibody, which blocks the membrane binding and action of human T-cell growth factor (TCGF), is strongly proposed to recognize TCGF receptor. We have demonstrated that anti-Tac antibody reacted with leukemic cells from patients with adult T-cell leukemia (ATL) and reacted with T-cell lines established from ATL cells. Although antigenic modulation, or down-regulation, of Tac antigen on activated normal T cells was induced by anti-Tac antibody, the expression of Tac antigen on ATL cells or T-cell lines was not affected when examined by the fluorescence-activated cell sorter (FACS) and the radioassay using 125I-staphylococcal protein A. These results indicate that regulation of Tac antigen-TCGF receptor is different between normal and malignant T cells, suggesting that failure of down-regulation of Tac antigen on leukemic cells by anti-Tac antibody may play an important role in the malignant proliferation of ATL cells.

Animals↗
PubMed1982

Modulation of Tac antigen on activated human T cells by anti-Tac monoclonal antibody.

A monoclonal antibody termed anti-Tac antibody is reactive with activated and functionally mature human T cells, but not reactive with resting T cells or B cells. We found that the expression of Tac antigen on activated T cells was inhibited by the addition of anti-Tac antibody in the culture of T cells activated with Con A or alloantigen. In the mixed lymphocyte culture, the expression of Ia-like antigen on allo-activated T cells was also inhibited by anti-Tac antibody, although the antibody does not recognize Ia-like antigen. However, anti-Ia monoclonal antibody did not suppress the expression of either Tac or Ia-like antigen. In addition, Tac antigen expressed on activated T cells was modulated by anti-Tac antibody cultured with activated T cells at 37 degrees C for 48 hr. Antigenic modulation, which means a specific loss of Tac antigen from the cell surface of T cells, was detected by the indirect immunofluorescence method. Tac antigen was reexpressed on T cells after restimulation when the anti-Tac antibody was removed, whereas Ia-like antigen already expressed on allo-activated T cells was not modulated by anti-Tac antibody. These results suggest that Tac and Ia-like antigens are carried on different molecules, both of which are closely linked in expression on activated T cells. The expression of Tac antigen may be essential for the following expression of Ia-like antigen.

Antibodies, Monoclonal↗
PubMed1981

Regulation of IgE response by IgE binding factors.

T lymphocytes from rats infected with Nippostrongylus brasiliensis (Nb) release a soluble factor with affinity for IgE that selectively potentiates the IgE response to an unrelated antigen. The factor is derived from Fc omega receptors on T cells, binds to surface IgE on precursors of IgE-forming cells, and enhances their differentiation. The factor had a molecular weight between 10,000 to 20,000 and an affinity for lentil lectin. T cells from Nb-infected rats formed another IgE-binding factor upon incubation with rat IgE. The factor has the ability to suppress rather than enhance the IgE response. The IgE-specific suppressive factor is comparable to IgE-potentiating factor with respect to molecular weight and affinity for IgE but it fails to bind to lentil lectin. The IgE-specific suppressive factor is formed by lymphocytes complete Freund's adjuvant-treated rats. The results strongly suggest that IgE-binding factors are involved in the regulation of IgE response.

Animals↗
PubMed1981

Regulatory role of IgE-binding factors from rat T lymphocytes. V. formation of IgE-potentiating factor by T lymphocytes from rats treated with Bordetella pertussis vaccine.

An i.p. injection of Bordetella pertussis vaccine (BP) into rats induced the formation of soluble factors that had affinity for IgE (IgE-binding factors). The factor was detected in the serum of BP-treated animals 5 to 7 days after the treatment. Their circulating lymphocytes as well as spleen cells spontaneously released IgE-binding factors in the serum of BP-treated rats and those released from their circulating lymphocytes had affinity for lentil lectin, and the ability to selectively potentiate an in vitro IgE response of DNP-OA primed cells to homologous antigen. The molecular size of IgE-potentiating factor was between 10,000 and 20,000, and was comparable to that formed by lymphocytes of rats infected with Nippostrongylus brasiliensis. Evidence was obtained that IgE-potentiating factor was derived from Fc epsilon R(+) T cells, with a T cell marker identified by monoclonal antibody W 3/25. Their production of IgE-potentiating factor may be the basis of the adjuvant effect of BP on the IgE response.

Animals↗
PubMed1981

Lymphocytes bearing Fc receptors for IgE. V. Effect of tunicamycin on the formation of IgE-potentiating factor and IgE-suppressive factor by con A-activated lymphocytes.

Attempts were made to induce the formation of soluble factors having affinity for IgE (IgE-binding factors) by activated T cells. Normal rat mesenteric lymph node (MLN) cells were cultured in 1 microgram/ml Con A for 48 hr or in 10 microgram/ml Con A for 72 hr, and Con A-activated lymphocytes were incubated with rat IgE. It was found that IgE induced an increase in the proportion of Fc epsilon R(+) cells in the Con A-activated cells and formation of IgE-binding factors. However, the nature of IgE-binding factors formed by the cells were different depending on the concentration of Con A for activation. Thus, IgE-binding factors formed by 10 microgram/ml Con A-activated cells had a high affinity for lentil lectin and enhanced the IgE-forming cell response of DNP-OA primed cells. In contrast, the majority of IgE-binding factors formed by 1 microgram/ml Con A-activated cells failed to bind to lentil lectin and suppressed the IgE response. Induction of Fc epsilon R by IgE on Con A-activated cells was prevented by tunicamycin, which inhibits protein glycosylation. This antibiotic did not prevent the IgE-induced formation of IgE-binding factors but changed the nature of the factors formed by 10 microgram/ml Con A-activated cells. The majority of IgE-binding factors formed in the presence of tunicamycin lacked affinity for lentil lectin and Con A, and suppressed, rather than enhanced, the IgE response. The nature and amount of IgE-binding factors formed by 1 microgram/ml Con A-activated cells was not affected by tunicamycin. The results suggest that glycosylation of IgE-binding factors during their biosynthesis is an important step in determining their biologic function.

Animals↗
PubMed1981

Lymphocytes bearing Fc receptors for IgE. VI. Suppressive effect of glucocorticoids on the expression of Fc epsilon receptors and glycosylation of IgE-binding factors.

Incubation of rat lymphocytes with homologous IgE induced an increase in Fc epsilon R(+) lymphocytes and the formation of IgE-binding factors. Pretreatment of rat lymphocytes with 1 to 5 microM dexamethasone, however, prevented the IgE-induced expression of Fc epsilon R on both B and T lymphocytes. Upon incubation with IgE, T cells activated with 10 micrograms/ml Con A produced IgE-potentiating factors that had affinity for lentil lectin and selectively enhanced the IgE response. Pretreatment of the Con A-activated T cells with dexamethasone, before incubation with IgE, changed the nature of IgE-binding factors formed by the cells. The majority of IgE-binding factors formed by the dexamethasone-treated, Con A-activated cells failed to bind lentil lectin Sepharose and selectively suppressed the IgE response. An injection of 0.2 mg dexamethasone into rats infected with Nippostrongylus brasiliensis markedly diminished the proportion of Fc epsilon R(+) lymphocytes in their mesenteric lymph nodes. The lymph node cells from the infected animals spontaneously released IgE-potentiating factors in vitro. However, the majority of IgE-binding factors formed by the mesenteric lymph node cells from the dexamethasone-treated, Nb-infected animals lacked affinity for lentil lectin and selectively suppressed the IgE response. The results indicate that glucocorticoid treatment prevented the glycosylation of IgE-binding factors and thereby changed the biologic activities of the factors.

Animals↗
PubMed1980

Lymphocytes bearing Fc receptors for IgE. IV. Formation of IgE-binding factor by rat T lymphocytes.

Culture of mesenteric lymph node cells from rats infected with Nippostrongylus brasiliensis resulted in the release of a soluble factor (IgE-binding factor) that can inhibit rosette formation of Fc epsilon R(+) lymphocytes with IgE-coated red cells. The factor is specifically absorbed with IgE-coated Sepharose. It has a m.w. of between 10,000 and 20,000. The major source of IgE-binding factor appears to be Fc epsilon R(+) T cells. The formation of IgE-binding factor by the lymphocytes was enhanced by IgE added to the culture medium. Evidence was obtained that Fc epsilon R(+) cells are involved in the induction of IgE-induced factor formation. Normal rat lymphocytes cultured alone failed to release IgE-binding factor, but incubation of normal lymphocytes with rat IgE resulted in the formation of IgE-binding factor and an increase in the proportion of Fc epsilon R(+) cells. It was also found that normal T cells formed the soluble factor upon incubation with IgE. In the induction of factor formation by normal lymphocytes, Fc gamma R(+) cells are essential; an Fc gamma R-depleted fraction failed to form IgE-binding factor upon incubation with IgE. The results suggest that interaction of IgE with Fc epsilon R(+) T cells and Fc gamma R(+) T cells induces the formation of IgE-binding factor(s).

Animals↗
PubMed1980

Regulatory role of IgE-binding factors from rat T lymphocytes. I. Mechanism of enhancement of IgE response by IgE-potentiating factor.

T lymphocytes in the mesenteric lymph nodes of rats infected with Nippostrongylus brasiliensis spontaneously released a soluble factor that selectively potentiated the IgE-forming cell response of antigen-primed cells to homologous antigen. The factor could enhance the IgE response of DNP-OA-primed cells to DNP-HSA and T cell-replacing factor. In contrast, the treatment of OA-primed T cells with the factor failed to enhance either the IgE or IgG response of the mixture of DNP-KLH primed cells and OA-primed T cells to DNP-OA. The results collectively suggested that the target cells of the IgE-potentiating factor are B cells. Indeed, IgE potentiating factor was absorbed by B cells rather than T cells or thymocytes. Evidence was obtained that IgE-potentiating factor could be absorbed by IgE-bearing B cells or IgE-coupled Sepharose, indicating that the factor had affinity for IgE. It appeared that the potentiating factor bound to IgE-bearing B cells and selectively enhanced the differentiation of IgE-B cells to IgE-forming cells. It was also found that the major source of the factor was Fc epsilon R-bearing T cells.

Absorption↗
PubMed1980

Regulatory role of IgE-binding factors from rat T lymphocytes. II. Glycoprotein nature and source of IgE-potentiating factor.

Previous experiments have shown that Fc epsilon receptor-bearing (Fc epsilon R(+)) T lymphocytes in mesenteric lymph nodes (MLN) of rats infected with Nippostrongylus brasiliensis (Nb) release a soluble factor that selectively potentiates the IgE response. The IgE-potentiating factor has affinity for IgE, and can be detected by the ability to inhibit rosette formation of Fc epsilon R(+) cells with IgE-coated erythrocytes. The factor was bound to IgE-coated Sepharose and was eluted from the beads at acid pH. It was also found that the IgE-potentiating factor binds to lentil lectin-Sepharose, indicating that the factor is a glycoprotein. The affinity of the factor for IgE was lost after treatment with trypsin but was maintained after treatment with neuraminidase. However, the ability of the factor to potentiate the IgE response was lost after neuraminidase treatment. The results suggested that the factor's binding site for IgE is associated with a protein (peptide) moiety but that its carbohydrate moiety is essential for its biologic activity. When MLN cells were incubated at 37 degrees C, a substantial amount of the IgE-potentiating factor was released into culture medium within 4 hr even in the presence of cycloheximide. Pretreatment of the cells with trypsin, which removed Fc epsilon R, markedly diminished the release of IgE-potentiating factor, suggesting that the factor is derived from Fc epsilon R on the cell surface.

Animals↗