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Biomedical subjects

M Yutoku

Publications and source records attributed to M Yutoku.

6 recordsLinked to original sources
PubMed1975

The expression on mouse lymphoid cells of Th-B, an antigen common to mouse B cells and thymus cells.

A new cell-surface antigen of mouse lymphocytes, which was found earlier on normal and malignant plasma cells and about half the normal thymus cell population, has been shown to be on mature B cells and on the least immunocompetent subpopulation of cells of the thymus. The antigen was first detected by the cytotoxic effect on relevant cells of an in vivo purified rabbit antiserum raised against cells of the mouse IgM-producing plasma cell tumor MOPC-104E. We have now used a cell-transfer method to examine the effect of this antiserum (RantiM104E) on immunocompetent lymphocytes of spleen, including separated splenic B and T cells and thymus and bone marrow cells. We have found the antigen on the immunocompetent B lymphocytes of the spleen, but not on any other of the immunocompetent cells examined. The method involves determining the effect of the antiserum on the development of plaque-forming cells in the spleens of irradiated mice that have received lymphocytes from immune or non-immune donors by treating the lymphocyyes with RantiM104E antiserum before transfer. Plaque-forming cells are suppressed when antiserum-treated spleen cells are transferred to the irradiated mice.This suppression was found to be due to action on only the splenic B cells. The helper activity of splenic T cells was not reduced significantly by antiserum treatment. Neither was the helper activity of thymus cells similarly treated reduced by the antiserum. We found, in fact, that the subpopulation of the thymus cells which is resistant to the antiserum was more immunocompetent than the total thymus cell population. In addition, the hydrocortisone-resistant thymus cells were also found to be resistant to the cytotoxic action of the antiserum. The antiserum had no effect on bone marrow cells in the cell-transfer procedure. The antigen involved, which we are designating "Th-B" appears to be a B cell line marker which appears relatively early during the differentiation of mouse B cells from precursor cells and is lost during maturation of T cells.

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PubMed1975

An experimental model for evaluation of factors in tumor escape from immunological attack.

A model system is presented for studying the factors involved in tumor immunity. The initial observations with this system concern the importance of dose and route of administration of tumor cells on tumor growth. The data show that myeloma tumor cells, when inoculated i.v.in relatively large numbers, are eradicated by the immune response of an allogeneic host; tumor cells administered i.v. in smaller number escape from immune attack even though the host has the potential to mount an immune response. BALB/c mouse myeloma cells (MOPC-21) were transplanted s.c., i.p., or i.v. into H-2-compatible allogeneic DBA/ 2 mice. There was a marked difference in the response of the host to tumor given s.c. or i.p. as compared to tumor given i.v. Thus s.c. or i.p. inoculation resulted in lethal tumor growth when 5 x 10-3 or more tumor cells were given. In contrast, the outcome of i.v. inoculation depended on tumor cell dose. Although small cell doses ( 5x 10-4 down to 10-2) resulted in lethal tumor gosulted in lethal tumor growth with only 10% survival, large cell doses (10-5 to 5 x 10-7) resulted in tumor rejection and 70% survival. DBA/2 mice possess the immunological ability to react agaist the tumor when large doses of tumor cells (10-7) are given i.v. or i.p., since spleen cells obtained from such mice were found to be able to suppress the growth of MOPC-21 when a mixture of spleen cells and tumor cells was inoculated. On the basis of these initial observations, our model appears to relate especially to the idea that, in autochithonous tumor development or in metastasis of tumor, a small number of antigenic tumor cells, perhaps even a single cell, usually grows into a frank tumor in spite of the immunological competence od the host to respond to the tumor cells.

Animals↗
PubMed1975

A surface membrane determinant shared by subpopulations of thymocytes and B lymphocytes.

Utilizing a quantitative fluorescence assay with the fluorescence-activated cell sorter (FACS), we have demonstrated that a rabbit antiserum obtained by immunization with cells of a mouse IgM-producing plasma cell tumor (MOPC104E) is reactive with at least two surface determinants, designated Th-B and ML2, on subpopulations of normal murine lymphocytes. The ML2 determinant is restricted to B lymphocytes. The Th-B determinant is shared by splenic B lymphocytes and a large subpopulation of thymocytes, the latter of which express a 3-fold higher density of Th-B on their surface than do the B lymphocytes. Neither Th-B nor ML2 were found on peripheral T cells or on brain, liver, or kidney cells. The available evidence suggesting that Th-B may be a stem cell determinant that is lost upon maturation is discussed.

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