Biomedical subjects

F Sendo

Publications and source records attributed to F Sendo.

At least 127 records · Page 7Linked to original sources

PubMed1976

Effect of combination treatment with cyclophosphamide and nonspecific passive immunization on a transplantable tumor in WKA rats.

Combination of cyclophosphamide (CY) and passive immunization with lymphoid cells sensitized to allogeneic tumor was studied in the treatment of a methylcholanthrene-induced transplantable fibrosarcoma in WKA rats. For determination of the most effective timing of combination treatment, rats given an injection of CY on Day 3 received passive transfer of the sensitized lymphoid cells on Day 0, 1, 2, 3, 4, or 6. A remarkable therapeutic effect was observed only when the passive transfer was combined on Day 4 with CY on Day 3. Rats inoculated with tumor succumbed in all cases without any treatment. After i.v. injection of CY on Day 3, 2 of 28 rats were cured (7.1%). Passive immunization with the sensitized lymphoid cells on Day 4 resulted in no therapeutic effect. After combination of CY on Day 3 and transfer of nonsensitized normal lymphoid cells on Day 4, 2 of 15 rats survived (13.3%). However, combination of CY and passive transfer of the nonspecifically sensitized lymphoid cells resulted in 23 survivors of 29 rats (79.3%).

Animals↗

PubMed1976

Nonspecific inhibition of tumor growth in vivo by admixed allogeneic tumor-sensitized lymphoid cells and identical inactivated allogeneic tumor cells.

With the in vivo tumor neutralization test (Winn test), growth of a transplanted (KMT-17) from Wistar-King-Aptekman rats was inhibited by allogeneic tumor (AH-66 from Donryu rats)-sensitized syngeneic lymphoid cells admixed with mitomycin C (MMC)-treated AH-66 cells. The observed tumor inhibition may be immunologically nonspecific, since no cross-antigens were detected by membrane immunofluorescence on the surfaces of KMT-17 and AH-66 cells. Close contact among KMT-17, AH-66-sensitized lymphoid cells and MMC-treated AH-66 cells was required for the inhibition of KMT-17 growth. AH-66 cells pretreated with formalin or ultrasonication lost tumor inhibitory activity when they were admixed with AH-66-sensitized lymphoid cells, and only MMC-treatment effectively preserved the tumor inhibitory activity of AH-66 cells. The sensitized spleen cells, draining lymph node, or peripheral blood cells inhibited tumor growth when they were admixed with MMC-treated AH-66 cells, whereas nucleated cells from bone marrow, thymus, or distal lymph node did not. Growths of KMT-17 were inhibited by admixed sensitized spleen cells and MMC-treated AH-66 even when pre-irradiated rats were used as recipients.

Animals↗

PubMed1975

Natural occurrence of lymphocytes showing cytotoxic activity to BALB/c radiation-induced leukemia RL male 1 cells.

Spleen cells from untreated young male and female C57BL/6 and C58 mice and of male C3H/He mice showed cytotoxic activity in vitro against BALB/c X-radiation-induced leukemia RL male 1 cells by 51Cr-releasing lymphocyte-mediated cytoxicity (LMC) tests, but old mice of these strains lacked LMC activity. In contrast, spleen cells from male and female AKR, BALB/c, and DBA/2 mice, and from female C3H/He mice had no appreciable LMC activity. The proportion of active cells in spleens from young (C57BL/6 times BALB/c)F1 or reciprocal hybrid mice was higher in females than in males. The specificity of the LMC reaction of RL male 1 cells, determined by LMC inhibition assays, was somewhat different from that of previously reported serologic X.1 tests. Thus the antigen detected by LMC has been tentatively designated X.1'. The main effector cells in this system were uncharacterized cells not adherent to glass surfaces or nylon-wool columns. These findings in RL male 1 leukemia extend the evidence for the presence of naturally occurring LMC. With the single unexplained exception of strain C3H/He, the LMC activity against RL male 1 cells, exhibited by untreated mice of various strains, corresponded with a previous classification of mouse strains immunologically as X.1 responders or as X.1 nonresponders according to their ability to reject X.1-positive leukemia cells.

Age Factors↗

PubMed1975

Change of antigenic expression on rat tumor cells after their transplantation.

Antigenic expression of 3-methylcholanthrene-induced transplantable fibrosarcoma KMT-17 cells was investigated in relation to days after ip transplantation. Cytotoxicity tests with antiserum against tumor-associated surface antigen of KMT-17 cells revealed that cytotoxic sensitivity and absorbing capacity decreased after transplantation, but they increased when other normal rats were given transplants of tumor cells. A decrease in the sensitivity was observed when immunosuppressively irradiated rats were given tumor transplants. Tumor cell density in the abdominal cavities of rats directly and absorbing capacity of KMT-17 cells to antiserum against the histocompatibility antigen did not change after transplantation. The possible mechanisms of antigenic change of KMT-17 cells were discussed.

Absorption↗

PubMed1975

Enhancement of host immune response to cell surface antigens by a preparation of Streptococcus hemolyticus.

A preparation (OK-432) of a low virulence strain, Su, of Streptococcus hemolyticus (Group A) has been found to possess 2 different effects on tumor cells: a) A direct pharmacological effect like other antitumor drugs, and b) an indirect effect through the enhancement of the host immune response. In order to examine the second effect, 2 different antigen systems were used, Gross (G) cell surface antigens (GCSAs) and the cell surface differentiation antigen PCl. At certain ages, untreated C57BL/6 and BALB/c mice occasionally produce natural antibodies to GCSAs and PCl, respectively. When the mice were injected intraperitoneally (i.p.) with OK-432 at 2 months of age, they produced natural antibodies to GCSAs or to PCl antigen, unlike untreated mice of the same strains at the same ages (negative controls), which produced no antibodies. The specificity of the antibodies was carefully examined by cytotoxicity tests. In addition, the activity of the natural antibodies was not neutralized with OK-432 itself. We have proven that OK-432 enhances the production of natural antibodies to specific cell-surface antigens.

Animals↗

PubMed1974

Tumor induction by murine sarcoma virus in AKR and C58 mice. Reduction of tumor regression associated with appearance of Gross leukemia virus pseudotypes.

Adult AKR and C58 mice injected intramuscularly with murine sarcoma virus, Moloney isolate (M-MSV), developed high incidence of nonregressing local tumors. Histologically, these tumors revealed the typical pleomorphism of M-MSV sarcomas; in some cases, however, neoplastic tissue showed a nodular or diffuse growth of monomorphic myoblastlike cells, reminiscent of clonal aggregates. No depression of immune reactivity was found in M-MSV-injected mice as evaluated by direct hemolytic plaque-forming cells against SRBC and by virus-neutralizing antibody production. The MSV recovered from the induced tumors proved to be, by neutralization assay, a Gross (G)-MSV pseudotype. Moreover, tumor cell suspensions absorbed out cytotoxic antibody directed against G-cell surface antigens. Therefore, the conclusion was drawn that MSV with envelope characteristics of endogenous G leukemia virus had formed in vivo through a phenotypic mixing phenomenon. The failure of tumors to regress has been interpreted as mainly due to the partial unresponsiveness of host immune reactivity towards G-MuLV specified antigens. Since MSV-tumors arose in AKR mice after a very long latent period, the possibility was considered that this relative resistance might depend on immunologic mechanisms. In fact, M-MSV-injected AKR mice immunodepressed by goat antimouse lymphocyte serum or rendered partially tolerant by neonatal M-MuLV inoculation developed sarcomas with higher incidence and with a shorter latency. Furthermore, the MSV recovered from these early tumors proved to be the original Moloney pseudotype.

AKR murine leukemia virus↗

PubMed1974