A Novel Monoclonal Antibody to Thymic Medullary Epithelial Cells Raised Against a Thymoma Cell Line of the Rat

A monoclonal antibody (mAb), RE12B2 was raised against a thymic thymoma cell line TAD1-3 and its specificity for the epithelial component of thymus assessed by immunohistochemical staining. The result revealed the mAb labeled cells in the medullary areas of the thymus. PIAS AREA study showed that the number of RE12B2 positive cells are reduced in the thymus of spontane-ous thymoma rat. Western immunoblotting revealed that RE12B2 recognized a protein with a molecular weight of 35 kDa. This mAb did not exhibit reactivity with cells in peripheral lymphoid organs

Electron microscopic observation of polyoma DNA component I isolated by CsCl-ethidium bromide density gradient centrifugation.

The DNA extracted from a purified preparation of polyoma virus was separated into two fractions situated in either light or dense bands by CsCl-ethidium bromide density gradient centrifugation. The electron microscopic examination of the DNA in each band showed the molecular configuration of linear and circular DNA, respectively.It was previously considered that the DNA in the dense band consisted component I (closed supercoiled circular DNA) of polyoma virus, however this band contained a number of open circular DNA molecules which increased the length of circumference. The influence of dye binding on the molecular configuration of closed supescoiled circular DNA is discussed

Review Intracellular Glutathione in Cellular Immunology

Glutathione is the most abundant intracellular tripeptide thiol and acts as a reducing agent and an antioxidant. Glutathione may regulate many enzymatic and pharmacological activities by changing the intracellular redox condition. Recent studies have accumulated evidence for important roles of glutathione in full competence of lymphocytes for such as activation, proliferation and induction of cytotoxicity. A decrease in intracellular glutathione may cause malfunction of lymphocytes, immunosuppression and apoptosis. A variety of immunological functions are determined on the basis of the balance between synthesis and con-sumption of intracellular glutathione

Clonal Heterogeneity in Drug Sensitivity of Primary and Metastatic Murine Tumor Cells Using a Clonogenic Assay

The heterogeneity with respect to the sensitivity to a cytotoxic agent of clones derived from a mouse fibrosarcoma tumor (MCA-F?) and its individual metastatic lung colonies has been examined. After 1 hr exposure of mitomycin C (MMC), the plating efficiency (PE) of parental tumor cell clones and metastatic cell clones were measured respectively, suggesting that the degree of clonal heterogeneity of primary tumor cells which showed different ancholage-independency was lower than that of metastatic tumors. The drug sensitivity of parental tumor cell clones also showed their heterogeneity and in the individual metastatic lung tumor cell clones as well, but with a rather high resistance. One (MCA-F-M2) out of 4 colonies in the lung, especially showed significantly high % PE in a clonogenic assay using 1 hr MMC exposure at 0.1 μg/ml concentration (mean % PE=19.7; P<0.005) and its clones showed almost the same homogeneous sensitivity within a growing colony in the lung. While, there existed not a small population of drug sensitive clones within these metastatic lesions. These findings indicate the clonal chemotherapeutic heterogeneity in metastatic lesions, and may provide, serious implications for the administration of antitumor drugs on the early differentiation of tumors

An Antiproliferative Monoclonal Antibody, 4F9, Reacts with a Subset of Human CD45 Molecules.

The 4F9 monoclonal antibody (IgM) was established for its ability to induce mild growth inhibition to a human T cell line, SUP-T13. The antibody reacted with all hematopoietic cell lines, but not with nonhematopoietic cell lines. Im-munoprecipitation and immunoblotting experiments showed that 4F9 recognized cell surface molecules with apparent molecular weights of between 190 and 220 kDa which varied slightly in size among the cell lines. Therefore, it was strong-ly suggsted that 4F9 recognizes a subset of human CD45 molecules. In immuno-histochemical analysis with paraffin-embedded tissue sections, 4F9 reacted with most lymphocytes except for germinal center B cells in lymph nodes and both medullary and cortical thymocytes. The results of the present study indicated that the anti-CD45, such as 4F9 antibody, affect growth of malignant T cells. The 4F9 antibody is useful in the immunohistochemical analysis of CD45 mole-cules in paraffin-embedded tissue sections

Clonal Diversity of the Expression of MHC Class I Antigens. and Endogenous Retroviral Antigens on the Oncogene-Induced Cell Transformation of BALB3T3 Cells-Different Regulatory Mechanisms for the Expression of Antigens

The effect of the activated oncogene transfection on the expression of MHC class I H-2Kd, Dd and Ld and endogenous retroviral antigens was analyzed on 21 clones independently derived from the same parental BALB3T3. These clones were obtained by transfecting BALB3T3 with EJ-ras, PyMT, c-myc, and v-src oncogenes. The expression of MHC class I H-2Ld and H-2Kd antigens was reduced in clones with high anchorage independent growth potential. However, clones with low or no anchorage independent growth potential displayed almost the same degree of expression as parental BALB3T3. The H-2Dd antigen was for the most part conserved. The reduced expression of H-2Kd antigen was com-pletely restored by IFN treatment, whereas that of H-2Ld antigen was only par-tially restored. Meanwhile, MuLV and MMTV antigens were expressed on parental BALB3T3. These antigens was down-modulated in all of the EJ-ras and in one of the v-src-transfected clones. However, all the PyMT-transfected clones expressed the antigens as much as parental BALB3T3 even in the clones with high anchorage independent growth potential. These data suggest that the MHC class I antigen expression is modulated with the transforming process of cells, whereas the endogenous retroviral antigen expression might be dependent upon the transfected oncogenes rather than the transforming phenotype of the cells

Antitumor Activity of Activated Lymphocytes and Macrophages by Liposome-borne Tumor-specific Transplantation Antigens on Postsurgical Tumor Recurrence in Murine

Liposome-borne tumor-specific transplantation antigens (TSTA) potentiated the antitumor activity of cytotoxic lymphocytes and macrophages (Mφ) much more efficiently than empty liposomes in murine. Mφ obtained from peritoneum and lung as well as cytotoxic T-lymphocytes (CTL) such as lymphokine-activat-ed killer (LAIC) cells and tumor infiltrating lymphocytes (TIL) showed higher inhibitory activity on metastatic tumor cell growth in lung. Among the effector lymphocytes in vivo, TIL showed desiable antitumor activity by way of intra-venous injection, while peritoneal Mφ showed high cytotoxicity by intraper-itoneal injection and intraveneously alveolar Mφ also showed high cytotoxic activity. These results suggest that the suitable administrations of liposome-borne TSTA may be useful in potentiating the tumoricidal effect of effector cells in vivo, especially TIL, CTL, and Mφ, and possibly may aid in overcoming tumor metastases