An enzyme-linked immunosorbent assay method was developed for the detection of antibodies to adult T-cell leukemia-associated antigens (ATLA). This new method, which is simpler than the currently used indirect immunofluorescence technique, should be useful for mass screening of anti-ATLA antibodies.

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Patients with filariasis were commonly observed until 1961-1970 in the Goto Islands, an area where adult T-cell leukemia (ATL) is endemic. The positive rate of antibodies to ATL virus-associated antigen among persons with a high antibody titer to filarial antigen was higher than that among persons with a low antibody titer in both sexes. Thus, filarial parasites might have some promoting effects on ATL virus infection and/or ATL virus proliferation among inhabitants in the endemic areas of filariasis and ATL.

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Multiple intralesional injections of quinonyl-muramyl dipeptide-66, a new synthetic immunoadjuvant, with a vehicle oil such as squalene or squalane resulted in the regression of line-10 hepatocarcinoma in strain-2 guinea pigs. This chemically synthesized adjuvant should be a useful immunotherapeutic agent for cancer.

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The dose-response curves for various compounds in the Ames test were analyzed by combining the least-squares method with cluster analysis. The following theoretical equation was employed: m(x)=(B+Sx)exp(-Tx), where m(x) is the number of revertants at the dose of x; B, the background number; S, the mutagenicity rate; and T, the toxicity rate. This equation is derived from a one-hit model modified to take account of the toxicity, and the parameters B, S and T are determined by applying the least-squares method for the fitting between theoretical and experimental dose-response curves with the use of the program package SALS (statistical analysis with least-squares fitting). With the values for B, S and T thus obtained, cluster analysis can clearly separate mutagenic and non-mutagenic compounds. Moreover, when cluster analysis into six groups is carried out, each group has quite characteristic parameter values. Consequently, this procedure is very useful for the classification of compounds according to the nature of the dose-response curve, that is, according to the nature of their mutagenic activity.

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Eight cases of choriocarcinoma were induced in WKA female rats by simple fetectomy without viral inoculation or administration of chemical carcinogens. Among them, one line has been successfully subcutaneously transplanted over 10 generations in syngeneic rats and this line was designated as RCHO. The histological appearance of RCHO consisted of trophoblastic giant cells and small basophilic tumor cells, which resembled normal rat placenta. RCHO possessed marked mammotropic and lactogenic activities in female recipients and induced atrophy of the testes in male recipients.

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The present study describes the establishment of T-cell lines from the peripheral blood of two Bloom syndrome (BS) patients and one healthy female by co-cultivation with a lethally irradiated human T-cell line (MT-2) carrying adult T-cell leukemia (ATL) virus (ATLV). The cell lines from normal and BS subjects exhibited cell surface markers compatible with T-cell origin, and BS T-cell lines retained the original cytogenetic characteristics of the syndrome. Even though phytohemagglutinin-stimulated BS lymphocytes from the two BS patients studied all showed high levels of sister chromatid exchange (SCE), one of the BS T-lines retained the high SCE level in 100% of the cells and the other BS T-line contained two populations, one with high SCE (70%) and the other with normal SCE (30%), at a relatively constant frequency over 6 months. Transformation of normal and BS cells by cocultivation with MT-2, which carries ATLV, did not cause karyotypic changes over 6 months. ATLV infection, chromosome instability, karyotypic abnormality and SCE in BS T-lymphocytes are also discussed.

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Serum neuron-specific enolase (NSE) was measured in 80 normal subjects, 20 patients with small cell carcinoma of the lung (SCCL) and 54 patients with non-small cell carcinoma (non-SCCL). The mean value in the control group was 2.1±0.4ng/ml (range, from 1.3 to 3.0ng/ml). Serum levels exceeding 7.5 ng/ml were tentatively defined as positive. Thirteen of 20 patients (65%) with SCCL had positive serum NSE levels, whereas 6 of 54 patients (11%) with non-SCCL had positive levels. Positive NSE in sera of patients was observed only in patients with advanced clinical stage of SCCL or non-SCCL. No correlation between serum NSE levels and metastatic sites could be found. The serum NSE levels in subtypes of SCCL were positive in 9 of 10 patients with oat cell carcinoma and 4 of 10 patients with intermediate cell carcinoma. Histological types of all positive cases with non-SCCL included large cell carcinoma. Serum NSE levels changed in parallel with the clinical course during the treatments. The data suggested that serum NSE may be a useful marker for monitoring the clinical course of lung carcinoma, especially of SCCL. Furthermore, the detection of NSE in non-SCCL is of interest in relation to the histogenesis of lung carcinomas which exhibit the properties of neuroendocrine tumors.

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Using the method of colony formation, the modifying effect of methylglyoxal bis(guanylhydrazone) (MGBG) was examined on 44°hyperthermia- and/or radiation-induced cell killing and on thermotolerance development after 44° exposure in Chinese hamster V-79 cells. After exposure to MGBG (10μM) for more than 6hr, cells became more sensitive to 44°hyperthermia. When an interval at 37°(up to 24hr) was interposed between MGBG and hyperthermic treatments, cell survival was not significantly increased, as compared with that for MGBG immediately followed by 44°. Cells treated with MGBG remained more thermosensitive, even after a 24hr interval. On the other hand, when cells were exposed to split dose 44°hyperthermia in the presence of MGBG during an interval of 6hr at 37°, the development of thermotolerance was not inhibited. After the combined treatments of MGBG followed by X-ray irradiation and hyperthermia, cell survival was markedly decreased, as compared with that in the case of X-ray irradiation alone or in combination with hyperthermia.

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The tumor growth and cell proliferation kinetics of B16 melanoma and transplantable squamous cell carcinoma (BSC tumor) in C57BL/6 mice were studied after single-dose X-ray and fast-neutron (2 MeV) irradiations. From tumor volume change studies, B16 tumor showed a high relative biological effectiveness (RBE) value (5.5) compared to that of BSC tumor (3.5). The tissue characteristics of the two tumors were not significantly different, but the post-irradiation changes in mitotic index (MI) and lebeling index (LI) were dependent on the tumor and on the nature of the radiation. After irradation, mitosis was immediately inhibited (G₂ block) but recovered within several hours in BSC and X-ray-irradiated B16 tumors. The neutron-irradiated B16 tumors showed no recovery up to the end of the observation period. After X-ray irradiation, of B16 tumors, LI showed an immediate reduction, while the reduction was delayed several hours (equal to G₁+M) in BSC tumors. The extent of reduction was dose-dependent, and its recovery was coincident with the recovery of mitosis. The change in LI of neutron-irradiated BSC tumors was similar to that with X-rays, but no change in LI was observed in neutron-irradiated B16 tumors over 18hr. From these results, it is assumed that the cell progression of B16 tumors is susceptible to ionizing radiation, and that G₁ block is induced as a result of irradiation.

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Thromboplastic and fibrinolytic activities of 8 lines of cultured human gastric cancer cells were estimated both in cell lysate and serum-free supernatant fraction. Furthermore, cell lysates with differing levels of thromboplastic activity were injected intravenously into congenitally athymic nude mice and the role of this activity in thrombus formation was examined. Thromboplastic and fibrinolytic activities of the cell lysate and the serum free-supernatant fraction varied from one line to another. There was no apparent correlation between these activities and the degree of histological differentiation of the original tumor. The thromboplastic activity was factor VII-dependent and factor IX-independent, indicating that it was attributable to tissue thromboplastin, although some factor VII-independent thromboplastic activity was also included in the cell lysate of two lines. Intravenous injection of the cell lysate with high thromboplastic activity produced more thrombi in the lung than that with low thromboplastic activity. This suggests that thromboplastic activity of cancer cells might play a significant role in the development of the hypercoagulable state in patients with gastric cancer.

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Immunization of rats with a purified mouse α-fetoprotein (AFP) suspended in Freund's complete adjuvant resulted in the production of antibodies that could precipitate both mouse and rat AFPs. A group of rats was immunized first and then fed a diet containing 0.06% 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB) for 10 weeks. In these rats the elevation of serum AFP as well as the development of hepatoma were markedly inhibited. Another group of rats was immunized after feeding the diet containing 3'-Me-DAB for 10 weeks. The development of hepatoma and production of serum AFP were also suppressed. In both groups the life span of the rats was prolonged by the immunization.

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The role of polymorphonuclear leukocytes (PMNs) as effector cells in tumor lysis was investigated in vitro. PMNs were obtained from the peritoneal cavity of C3H/He mice injected ip with 2ml of 12% casein sodium. These PMNs could lyse murine MM46 tumor cells in the presence of the plant lectin, wheat germ agglutinin (lectin-dependent PMN-mediated cytolysis). PMNs alone did not cause cytolysis. PMNs obtained 6hr after casein injection were effective against tumor target cells but those obtained 3hr after the injection were not. Other lectins, such as concanavalin A, phytohemagglutinin, pokeweed mitogen, soybean agglutinin, Ulex europaeus agglutinin, Lens culinaris hemagglutinin and Bauhinia purpurea agglutinin, did not cooperate with PMNs in tumor lysis. Antitumor antibody was another mediator that induced tumor lysis in cooperation with PMNs (antibody-dependent PMN-mediated cytolysis). These results indicate that PMNs can lyse tumor cells in the presence of appropriate mediators.

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The mechanisms of tumor lysis by polymorphonuclear leukocytes (PMNs) were investigated. In antibody-dependent PMN-mediated cytolysis (ADPC), sensitized tumor cells were specifically lysed via Fc receptors on PMNs. On the other hand, lectin-dependent PMN-mediated cytolysis (LDPC) caused nonspecific lysis of several murine tumors after recognition of carbohydrate moieties on the cell membrane of both PMNs and tumor cells. Both ADPC and LDPC depended on glycolysis, and cytotoxicity was mediated by reactive oxygen species; LDPC was dependent on superoxide and ADPC on the myeloperoxidase system. The participation of reactive oxygen species in PMN cytotoxicity was also demonstrated by pharmacological triggering with phorbol myristate acetate. These results indicate that reactive oxygen species have an important role in tumor killing by PMNs and that ADPC and LDPC have partly different cytolytic processes as well as different recognition steps.

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Combination therapy by intralesional injection of OK432 followed by intraperitoneal administration of lentinan and bacterial lipopolysaccharide caused almost complete regression of solid-type tumor MH134. All three components were needed for maximal antitumor activity. Mice in which MH134-tumor had regressed due to this combination therapy showed an augmented antitumor delayed hypersensitivity reaction (measured by the footpad test) and resistance to rechallenge with MH 134, but they had no cytolytic antibodies in their serum detectable by the complement cytotoxicity test. The possible importance of local inflammation induced by OK432 in this combination therapy is discussed.

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The antitumor activity of a marine bacterium, Vibrio anguillarum, against Ehrlich carcinoma cells in ddY mice was investigated. The aqueous layer obtained by the hot phenol-water procedure exhibited more antitumor activity than did the middle layer or the phenol layer. This finding indicates that lipopolysaccharide (LPS) derived from V. anguillarum exhibits significant antitumor activity. In fact, mice injected with LPS obtained by ultracentrifugation and treatment with RNase had a longer mean survival period than the control mice. V. anguillarum LPS also inhibited the growth of syngeneic fibrosarcoma induced by 3-methylcholanthrene in C57BL/6 mice. V. anguillarum LPS possesses no 2-keto-3-deoxyoctonate, a regular sugar component of the core region of most gram-negative bacterial LPS, suggesting that 2-keto-3-deoxyoctanate is unnecessary for the antitumor activity of LPS.

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Both ribose 1-phosphate and deoxyribose 1-phosphate, which were effective in increasing the formation of antineoplastic fluoronucleotides and fluoro-RNA from 5-fluorouracil (5-FU) in the intact cells of Ehrlich mouse ascites tumor, potentiated the antitumor effect of 5-FU. Ethylenediaminetetraacetate, which stimulates the formation of only fluororibonucleotides from 5-FU in intact Ehrlich tumor cells, was ineffective in the potentiation of 5-FU antitumor activity. The relationship between the increased metabolite formation from 5-FU and the antitumor effect of 5-FU is discussed.

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The chemotherapeutic effect of the 5-fluorouracil (5-FU)-guanosine 5'-monophosphate (GMP) combination in various mouse tumor systems was compared with that of 5-FU monotherapy. Antitumor activity of 5-FU against L-1210 leukemia was potentiated without increasing its toxicity to the host when GMP at 30-100mg/kg/day was injected simultaneously with 5-FU. Any time interval between the administrations of 5-FU and GMP diminished the increase in survival. Moreover, the combination of 5-FU and GMP at 100mg/kg/day produced marked antitumor effects in the P-388 leukemia, ascites sarcoma 180, and Ehrlich ascites carcinoma systems. GMP also potentiated the antitumor activity of 5-FU in solid tumor systems (adenocarcinoma 755 and Lewis lung carcinoma) when given by intravenous injection, but not intraperitoneal injection. The therapeutic effect of 5-FU on various murine tumors was markedly potentiated by GMP at 100mg/kg/day or less without increasing the toxicity to the host.

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Growth inhibitory activities of both human fibroblast (HuIFN-β) and lymphoblastoid (HuIFN-α) interferons against 17 human cultured cell lines derived from leukemias and lymphomas were measured quantitatively by regrowth assay. Daudi cells were the most sensitive to both interferons. Three B-cell lines, one T-cell line and one non-T, non-B cell line were moderately sensitive to both interferons. Although the levels of sensitivity of these cell lines to the interferons were different, cells could be killed by the interferons. Eleven other cultured cell lines including three B-cell lines, three T-cell lines, two non-T, non-B cell lines, two myeloid cell lines and one monocytoid cell line were not sensitive to these interferons. The results indicated that the growth inhibitory activity of interferons was not always cell lineage-specific and cell lines which were sensitive to the one interferon were always sensitive to the other interferon, although the level of sensitivity was different. Cytocidal action of interferons was analyzed by use of the most sensitive Daudi cells. The results indicated that both interferons had a time-dependent cytocidal action, but not a concentration-dependent one. Knowledge of the mode of the cytocidal action may be useful for the design of optional therapeutic schedules using the interferons. The prediction of clinical effectiveness of interferon against hematologic malignancies is discussed, based on the level of in vitro sensitivity of cultured leukemia and lymphoma cell lines.

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Daily intratumor injection of human fibroblast interferon (HuIFN-β) resulted in significant growth inhibition of human gliomas transplanted into nude mice. Light and electron microscope examinations were conducted to estimate the efficacy of HuIFN-β. A 29-day daily treatment with HuIFN-β induced complete regression of oligodendroglioma KG-1-a slowly growing tumor line positive for S-100 protein and negative for glial fibrillary acidic protein (GFAP)-in 9 out of 10 mice receiving 6×10⁵IU and 6 out of 9 given 1×10⁵IU. In mice with glioblastoma multiforme TMIMS-583, which showed more rapid growth and was positive for GFAP, dose-dependent growth inhibition was observed during 23 days of HuIFN-β administration. Pathological changes of TMIMS-583 induced by HuIFN-β were characterized by a decrease of the metaphase tumor cells, by enhanced degeneration of tumor cells with stromal reaction and round cell infiltrates, and by prominence of multinuclear giant cells containing glial filaments. Tumor weights were well correlated with the number of tumor cells in the metaphase (r=0.89)

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