Stimulatory effect of Holy basil and Thai basil on mouse spleen cell proliferation

Study was conducted on mouse spleen cells, cultured and incubated in-vitro with Holy basil and Thai basil, to observe their effect on proliferation. Four dilutions, namely 1:1, 1:5, 1:25, and 1:125, for both Holy basil and Thai Basil were used separately, in presence and absence of mitogen, Concanavalin A (Con A) to stimulate the T cells. Cell proliferation was monitored by 3 H- thymidine radioisotope incorporation. Spleen cells (macrophages, B and T cells) showed significantly more proliferation at 1:1 dilution than control (cells with no factor), incubated with Holy basil (in assay without Con A). Spleen T cells, however, did not show any significance in proliferation at same dilution, 1:1, with Holy basil with Con A. All other dilutions (with or without Con A), for either Holy basil or Thai basil, did not show any significant changes in proliferation when compared to control.

Assessment of chromosome aberrations in large Japanese field mice (Apodemus speciosus) in Namie Town, Fukushima

PURPOSE

After the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in Japan on March 11 2011, the surroundings became contaminated with radionuclides. To understand the possible biological effects after chronic low dose-rate radiation in contaminated areas of Fukushima, we assessed the effects in large Japanese field mice (Apodemus speciosus) by means of chromosome aberration analysis.

MATERIALS AND METHODS

We collected A. speciosus in five sites around Namie Town, Fukushima (contaminated areas) and in two sites in Hirosaki City, Aomori (control areas, 350 km north of FDNPP) from autumn 2011 to 2013. The number of mice captured and ambient dose-rates were as follows: high (n = 11, 10.1-30.0 µGy h^-1), moderate (n = 10, 5.7-15.6 µGy h^-1), low (n = 12, 0.23-1.14 µGy h^-1) and control (n = 20, 0.04-0.07 µGy h^-1). After spleen extraction from rodents, spleen cell culture was performed to obtain metaphase spreads. Chromosome aberrations were assessed on Giemsa-stained metaphase spreads.

RESULTS

Although the mice in the contaminated areas were chronically exposed, there was no radiation-specific chromosome aberrations observed, such as dicentric chromosomes and rings. Some structural aberrations such as gaps and breaks were observed, and these frequencies decreased annually in mice from Namie Town.

CONCLUSION

These findings suggest that chromosome aberration analysis is useful to evaluate and monitor radiation effects in wild animals.

In Vitro Anti-inflammatory Effects of the Phenylbutyric Acid Metabolite Phenylacetyl Glutamine

Sodium 4-phenylbutyrate (PBA), which exerts a wide range of anti-inflammatory effects, is rapidly cleared from the body (approximately 98%) by urinary excretion by 24 h after oral treatment in humans. PBA was almost entirely excreted to urine as phenylacetyl glutamine (PAGln). However, no data describe the potential anti-inflammatory effects of PAGln. The purpose of this study was to evaluate the anti-inflammatory effects of PAGln on mouse spleen cells and peritoneal cavity cells, and explore the potential mechanism underlying this effect. PAGln was added to mouse spleen cell cultures stimulated by concanavalin A, or mouse peritoneal cavity cell cultures stimulated by lipopolysaccharide. After 72 h of culture, levels of inflammatory cytokines in culture supernatants were measured using a sandwich enzyme-linked immunosorbent assay system, and levels of inflammatory proteins were assessed by Western blotting. PAGln significantly inhibited inflammatory cytokine (interferon-γ, interleukin-6, and tumor necrosis factor-α) production, decrease of cell number in the spleen cell, and suppressed the expression of inflammatory proteins (nuclear factor κB, and inducible nitric oxide synthase). These results suggest that PAGln possesses anti-inflammatory activity via inhibition of T cell activation and Toll-like receptor 4 signaling. This study of the anti-inflammatory mechanism of PAGln provides useful information about its potential for therapeutic applications.

Enhanced differentiation of intraepithelial lymphocytes in the intestine of polymeric immunoglobulin receptor-deficient mice

To clarify the effect of secretory IgA (sIgA) deficiency on gut homeostasis, we examined intraepithelial lymphocytes (IELs) in the small intestine (SI) of polymeric immunoglobulin receptor-deficient (pIgR(-/-) ) mice. The pIgR(-/-) mice exhibited the accumulation of CD8αβ(+) T-cell receptor (TCR)-αβ(+) IELs (CD8αβ(+) αβ-IELs) after weaning, but no increase of CD8αβ(+) γδ-IELs was detected in pIgR(-/-) TCR-β(-/-) mice compared with pIgR(+/+) TCR-β(-/-) mice. When 5-bromo-2'-deoxyuridine (BrdU) was given for 14 days, the proportion of BrdU-labelled cells in SI-IELs was not different between pIgR(+/+) mice and pIgR(-/-) mice. However, the proportion of BrdU-labelled CD8αβ(+) -IELs became higher in pIgR(-/-) mice than pIgR(+/+) mice 10 days after discontinuing BrdU-labelling. Intravenously transferred splenic T cells migrated into the intraepithelial compartments of pIgR(+/+) TCR-β(-/-) mice and pIgR(-/-) TCR-β(-/-) mice to a similar extent. In contrast, in the case of injection of immature bone marrow cells, CD8αβ(+) αβ-IELs increased much more in the SI of pIgR(-/-) TCR-β(-/-) mice than pIgR(+/+) TCR-β(-/-) mice 8 weeks after the transfer. αβ-IELs from pIgR(-/-) mice could produce more interferon-γ and interleukin-17 than those of pIgR(+/+) mice, and intestinal permeability tended to increase in the SI of pIgR(-/-) mice with aging. Taken together, these results indicate that activated CD8αβ(+) αβ-IELs preferentially accumulate in pIgR(-/-) mice through the enhanced differentiation of immature haematopoietic precursor cells, which may subsequently result in the disruption of epithelial integrity.

Generation of specific antitumor reactivity by the stimulation of spleen cells from gastric cancer patients with MAGE-3 synthetic peptide

The induction of cytotoxic T lymphocytes (CTL) from peripheral blood mononuclear cells (PBMC) using MAGE peptide has been investigated in order to use MAGE antigens immunotherapeutically. We therefore developed a simplified method for inducing peptide-specific CTL that kill tumor cells expressing MAGE from the PBMC of either healthy donors or even cancer patients. Since the spleen is a major lymphoid organ, we used a simple method to examine the capacity of spleen cells to generate MAGE-specific CTL by in vitro stimulation with MAGE peptide in gastric cancer patients. The CTL responses could thus be induced from unseparated spleen cells in HLA-A2 patients with gastric carcinoma expressing MAGE-3 by stimulating these cells with autologous spleen cells pulsed with HLA-A2-restricted MAGE-3 peptide as antigen-presenting cells and by using keyhole limpet hemocyanin and interleukin-7 for the primary culture. The induced CTL were thus able to lyse HLA-A2-positive carcinoma cells transfected with MAGE-3 and expressing MAGE-3, as well as the target cells pulsed with the peptide, in an HLA-class-I or -A2-restricted manner. Since MAGE-specific CTL could be induced from the spleen cells of gastric cancer patients, the spleen appears to play an important role in either clinical tumor vaccination or the treatment of cancer patients by adoptive immunotherapeutic approaches using the MAGE peptide.

Role of macrophages, interferon gamma and procoagulant activity in the resistance of genetic heterogeneous mouse populations to mouse hepatitis virus infection

Genetic heterogeneous mouse populations selected for high (HIII) and low (LIII) antibody response were used to study some aspects of mouse hepatitis virus 3 (MHV3) infection, such as the resistance pattern, virus replication in the liver and peritoneal exudate or in cultured peritoneal macrophages, the interferon (IFN) synthesis in the serum and peritoneal exudate and the procoagulant activity (PCA) of the peritoneal exudate (PEC) and spleen cells (SC). The HIII mice, when compared to their LIII mice counterparts, were susceptible to MHV3 infection showing higher virus titres in the liver and peritoneal exudate, comparable IFN alpha/beta or IFN gamma titres in the peritoneal exudate or in the serum, and higher levels of PCA of PEC and SC. A higher virus titre was detected in the supernatants of HIII mouse macrophages infected with MHV3. The activation of HIII mouse macrophages with LPS, IFN alpha/beta or IFN gamma, in contrast to that of LIII mouse macrophages, did not induce an antiviral effect with partial restriction of the MHV3 replication. The LPS antiviral activity was shown to be partially exerted by IFN alpha/beta synthesis. The IFN gamma was shown to be more effective in inducing an antiviral state in LIII macrophages, when compared to IFN alpha/beta. The data obtained are consistent with the notion that the resistance mechanisms to the MHV3 infection involve the PCA and the sensitivity of macrophages to IFN.

Responses of mice to murine coronavirus immunization

Oral and/or intranasal inoculation of susceptible mouse genotypes with the JHM strain of mouse hepatitis virus (MHV-JHM) consistently results in T cell dysfunction as reflected by in vitro proliferative responses to mitogens or allogeneic cells. One approach to examining the mechanism responsible for the observed functional T cell suppression is to determine whether virus replication is required for its induction. To this end, mice were inoculated oronasally with MHV-JHM that was inactivated with short-wave ultraviolet light, beta-propiolactone or psoralen. Mice were also inoculated with live MHV-JHM after recovery from homotypic or heterotypic MHV infection. Spleen cells from BALB mice inoculated oronasally with inactivated MHV-JHM yielded extremely variable in vitro proliferative responses after concanavalin A stimulation. MHV-susceptible mice exposed oronasally or intraperitoneally to virus inactivated by any of the minimum effective treatments failed to seroconvert. Immunization with psoralen-treated virus intraperitoneally in Freund's complete adjuvant or oronasally failed to protect from live virus challenge, but survivors had elevated virus-specific serum IgG antibody titers compared to mock-immunized controls at two weeks post-challenge. Spleen cells from mice that were challenged after recovery from homotypic live virus infection did not exhibit the profound in vitro T cell suppression normally observed during the acute stage of primary infection. In contrast, MHV-JHM challenge of mice vaccinated with heterotypic live MHV-S resulted in significantly depressed in vitro T cell function. The combined data suggest that either virus replication or exposure to more concentrated antigen may be required for induction of the dramatic T cell dysfunction that occurs as a consequence of MHV-JHM infection as well as for a detectable MHV-specific humoral response.

In vivo tumor growth enhancement by granulocyte colony-stimulating factor

The intraperitoneal administration of human recombinant granulocyte colony-stimulating factor (G-CSF) enhanced the growth of intradermally inoculated tumor in mice; in a Meth A fibrosarcoma model, G-CSF administration significantly shortened the latency before tumor appearance, accelerated the increase of tumor size, shortened the survival time of tumor-bearing mice and increased the incidence of lethal tumor growth. A similar growth-enhancing effect of G-CSF was observed in models employing Meth 1 fibrosarcoma, colon carcinoma 26, and L1210 leukemia, although not all the effects were statistically significant. In vitro study showed that G-CSF did not enhance Meth A growth in suspension culture or in soft agar. These data suggest that G-CSF enhances the Meth A growth not directly but through the mediation of host factors. The accumulation of neutrophils was histologically observed in the tumor nodule, the blood, and the spleen in mice given G-CSF repeatedly. The spleen cells and the peripheral blood leukocytes of G-CSF-injected mice enhanced Meth A growth in vitro as compared with those of mice injected with physiological saline. These results suggest the possibility that the in vivo growth of tumor cells was enhanced by G-CSF-induced overproduction of cells including neutrophils.

Phorbol ester-induced enhancement in lytic activity of CD8+ splenic T cells from low-dose melphalan-treated MOPC-315-tumor bearers

We have previously shown that while spleen cells from untreated mice bearing a large MOPC-315 tumor are not cytotoxic in vitro for MOPC-315 tumor cells, spleen cells obtained from such mice on day 7 after low-dose melphalan (L-phenylalanine mustard); L-PAM therapy exert a substantial anti-MOPC-315 cytotoxicity [Mokyr et al. (1989) Cancer Res 49: 4597]. Here we show that this anti-MOPC-315 lytic activity is evident by day 5, and peaks on day 7 after the low-dose chemotherapy, at a time when the mice are actively engaged in tumor eradication. Short-term exposure of spleen cells from mice bearing a MOPC-315 tumor and treated with low-dose L-PAM (L-PAM TuB mice) to phorbol 12-myristate 13-acetate (PMA) was found to enhance greatly the ability of these spleen cells to lyse MOPC-315 tumor cells. The highest level of anti-MOPC-315 cytotoxicity was obtained when spleen cells from tumor-bearing mice that had received chemotherapy 7 days earlier were exposed to PMA at a concentration of 1-10 ng/ml. The exertion of the enhanced anti-MOPC-315 lytic activity by L-PAM TuB spleen cells exposed to PMA was found to require CD8+, but not CD4+, T cells. The apparent specificity of the lytic activity exerted by the PMA-stimulated L-PAM TuB spleen cells was illustrated not only by the inability of the spleen cells to lyse an allogeneic, antigenically unrelated thymoma (EL4), but also by their relatively weak lytic activity for two antigenically related syngeneic plasmacytomas. In addition, when EL4 target cells were admixed with MOPC-315 tumor cells, the lytic activity triggered in the L-PAM TuB spleen cells by the MOPC-315 tumor cells plus PMA was not effective in lysing the antigenically unrelated target cells. Moreover, even in the presence of the calcium-specific ionophore, ionomycin, L-PAM TuB spleen cells exposed to PMA were unable to lyse the EL4 target cells. Thus, fresh CD8+ splenic T cells from L-PAM TuB mice that are in the process of eradicating a large MOPC-315 tumor as a consequence of low-dose L-PAM therapy can be triggered with PMA to exert enhanced lytic activity against MOPC-315 tumor cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Eradication of a large MOPC-315 tumor in athymic nude mice by chemoimmunotherapy with Lyt2+ splenic T cells from melphalan-treated BALB/c mice bearing a large MOPC-315 tumor

We have previously shown that spleen cells from BALB/c mice that are in the process of eradicating a large MOPC-315 tumor following low-dose (2.5 mg/kg) melphalan (L-phenylalanine mustard) therapy are effective in preventing tumor progression upon adoptive transfer into BALB/c mice bearing a barely palpable tumor that had been treated with a subcurative dose of melphalan [Mokyr et al. (1989) Cancer Res 49:4597]. Here we show that such spleen cells in conjunction with a subcurative dose of drug (adoptive chemoimmunotherapy, ACIT) can cause the complete regression of a large (15-20 mm) s.c. MOPC-315 tumor in a large percentage of T-cell-deficient (athymic nude) tumor-bearing mice. Spleen cells that were effective in ACIT of athymic nude mice displayed in vitro a substantial direct lytic activity against MOPC-315 tumor cells, and the lytic activity was greatly enhanced when the spleen cells were cultured for 5 days with or without mitomycin-C-treated MOPC-315 stimulator tumor cells. The cells responsible for the therapeutic effectiveness of the spleen cells in ACIT of athymic nude mice, as well as the cells responsible for the direct in vitro anti-MOPC-315 lytic activity of the spleen cells, were of the Lyt 2 and not the L3T4 phenotype. Most of the athymic nude mice that completely eradicated a large MOPC-315 tumor as a consequence of ACIT were capable of rejecting a challenge with 30-100 times the minimal lethal tumor dose for 100% of normal BALB/c mice administered more than 1 month after the ACIT. The ability of these athymic nude mice to resist the tumor challenge was associated with the presence of a greatly elevated percentage of cells expressing T cell surface markers in their spleens. Thus, it is conceivable that splenic Lyt 2+T cells from melphalan-treated BALB/c mice bearing a large MOPC-315 tumor mediate their therapeutic effectiveness in ACIT of athymic nude mice bearing a large MOPC-315 tumor, at least in part, through direct cytotoxicity for MOPC-315 tumor cells. In addition, eradication of a large MOPC-315 tumor through cooperation between antitumor immunity and melphalan toxicity endues the athymic nude mice with an elevated percentage of T cells in their secondary lymphoid organs, and these T cells are probably responsible for the long-lasting protective antitumor immunity exhibited by these mice.

Indomethacin modulation of adriamycin-induced effects on multiple cytolytic effector functions

The anticancer agent, Adriamycin (ADM), in addition to being a potent cytotoxic drug has been shown to be an effective immunomodulator. This study was undertaken to determine whether ADM-induced changes in the production of prostaglandins (particularly PGE2) are involved in ADM-associated modifications of selected host defenses. Spleen cells from normal or ADM-treated (5 mg/kg; day -5) C57BL/6 mice were assessed for the following activities: fresh (day 0) and cultured natural killer (NK), cytotoxic T lymphocyte, lymphokine-activated killer (LAK), Fc-dependent phagocytosis and tumoricidal macrophage. All activities were assessed with and without the addition of indomethacin, an inhibitor of the first step of the cyclo-oxygenase pathway of prostaglandin synthesis. Depending on culture conditions, the cytotoxic T lymphocyte and splenic tumoricidal macrophage activities were either unaffected or were augmented by ADM treatment of the spleen donor mice or by addition of indomethacin to the culture, and these effects were apparently independent of one another. In contrast, ADM treatment generally resulted in reduced NK and LAK activities relative to control and elevated Fc-dependent phagocytosis. The addition of indomethacin to the culture effectively reversed these effects. Furthermore, spleen cells from ADM-treated mice were found to produce twice the amount of PGE2 in culture compared to cells from untreated mice. Finally, the direct addition of PGE2 to NK cultures resulted in a dose-dependent inhibition of NK activity and the dose required was comparable to the amount of PGE2 produced by cultured spleen cells from ADM-treated mice. Taken together, these results indicate that at least some of the immunomodulatory effects of ADM are an indirect result of ADM-induced changes in PGE2 production.

Immunosuppression in murine renal cell carcinoma. I. Characterization of extent, severity and sources

Four cell-mediated immunological responses related to tumor elimination have been examined in mice injected with a transplantable renal cell carcinoma (Renca). Lymphokine-activated killer (LAK) cells generated in vitro from spleen cells of normal mice were capable of attacking Renca, EL-4, P815 and YAC-1 targets, but those from mice bearing Renca for 3 weeks could not. Natural killer activity, stimulated in vivo by administering poly(I) poly(C), was less than 50% of normal in Renca-bearing hosts. In addition, development of cytotoxic T lymphocytes to allogeneic targets was markedly inhibited in mice possessing the renal tumor. Finally, the delayed hypersensitivity response to a dermally applied hapten was approximately 70% less than normal in tumor-bearing mice, no matter whether the tumor existed subcutaneously or intrarenally. A kinetic study of the development of non-responsiveness using the LAK assay showed onset of poor response at 1 week, which became maximal within 3 weeks following receipt of tumor subcutaneously. The immunological depression was seen to be attributable in part to suppressor cells present among spleen cells but not bone marrow cells of tumor-bearing hosts. The suppressor cells prevented in vitro LAK generation by normal spleen cells and, when adoptively transferred to normal mice, they inhibited natural killer stimulation and delayed hypersensitivity generation. Another source of immunological down-regulation was provided by Renca cells themselves. Incorporation of Renca cells that had been X-irradiated with 30,000 rad into cultures of normal and Renca-derived splenic cells suppressed replication of both almost completely. Furthermore, the presence of X-irradiated Renca cells in cultures of normal spleen cells prevented development of LAK cells. Thus, the suppression seen in Renca-bearing mice derives from multiple sources and whether each is in any way related to the other has been discussed. Identification of the phenotypes of cells responsible for the lymphoid cell-mediated suppression and examination of its elimination are communicated in the companion paper.

Comparison of T suppressor factors from tumour-bearing mice and mice immunized with a monoclonal anti-idiotypic antibody

Certain dosage schedules of a monoclonal anti-idiotypic antibody (related to a murine bladder carcinoma) were found to induce suppressor factor production by syngeneic mice. This suppressor factor resembled the factor from tumour-bearing mice with respect to idiotype specificity, possession of molecular markers (reactive with anti-IJ and B16G antibodies) and production by Lyt2+IJ+ T cells in spleen cell cultures. The two factors differed with respect to Igh restriction in an in vitro assay (leucocyte adherence inhibition) and ability to suppress the induction of delayed-type hypersensitivity to tumour antigen.

Major-histocompatibility-complex-class-II-positive cells and interleukin-2-dependent proliferation of immune T cells are required to reject carcinoma cells in the guinea pig

Tumor immunity induced by bacillus Calmette-Guérin was studied in the line 10 hepatocellular carcinoma (line 10) in the strain-2 guinea pig. Line 10 immunity was investigated in vitro with a lymphocyte proliferation assay using line 10 tumor protein extracted with 3 M KCl and in vivo by adoptive transfer of line-10-immune spleen cells. Monoclonal antibodies against guinea pig leucocyte markers were used to block functional properties of the immune cells in order to determine which cell types or cell markers are involved in the immune response to the line 10 tumor. In vitro cells from the spleen, peripheral blood and regional lymph node of immune animals reacted with a proliferative response to line 10 protein. This antigen-specific response was caused by T cells and was regulated by major histocompatibility complex (MHC) class II molecules. In blocking experiments it was found that CT5 (anti-PanT), or MSgp4 [anti-(MHC class I antigen)] monoclonal antibodies did not block but sometimes stimulated the proliferative response. The effect of H159 (anti-PanT) was irregular, while H155 [anti-(T helper)], and 5C3 [anti-(IL-2 receptor)] monoclonal antibodies blocked the response almost completely. We studied the relevance of the results in vitro obtained and found that mAb 5C3 [anti-(IL-2 receptor)] inhibited the adoptive transfer of line 10 immunity, suggesting that the rejection of line 10 cells is caused by a mechanism that is interleukin-2 (IL-2)-dependent. Moreover, complement lysis of MHC-class-II-antigen-positive immune spleen cells inhibited completely the rejection of the line 10 tumor cell challenge in the adoptive-transfer experiments. In conclusion, our data show that MHC class II molecules or cells possessing these molecules are involved in immunity against line 10 tumor cells, as (a) monoclonal antibodies against MHC class II antigens inhibited the in vitro proliferative response of T cells to tumor antigens and (b) removal of MHC-class-II-positive immune spleen cells abrogated the antitumor effect in the adoptive-transfer experiments. Interleukin-2-dependent proliferation of immune T cells is required for the rejection of line 10 tumor cells.

Regression mechanisms of mouse fibrosarcoma cells after in vitro exposure to quercetin: diminution of tumorigenicity with a corresponding decrease in the production of prostaglandin E2

We have previously reported that both regressor (QR) and progressor (metastatic, QP) clones were obtained after the in vitro exposure of a mouse fibrosarcoma BMT-11 cl-9 to quercetin. In this study, we investigated possible mechanisms of spontaneous regression of QR clones as compared with tumorigenic QP and BMT-11 cl-9 tumor clones. We observed that BMT-11 cl-9 cells produced relatively high amounts of prostaglandin E2 (PGE2) during in vitro culture. The average production by 11 subclones of BMT-11 cl-9 cells was 9236 +/- 2829 pg/ml whereas that by 9 QR clones was 3411 +/- 2213 pg/ml (P less than 0.02). Indomethacin not only inhibited in vitro PGE2 synthesis by QP clones (high-PGE2 producers) but also the s.c. growth of QP clones in mice. Chronological changes in host immune responses to tumor-associated antigen were measured by cytotoxic T lymphocyte (CTL) activity examined after mixed lymphocyte/tumor cell culture of spleen cells obtained from tumor-bearing mice. The CTL activity disappeared abruptly in the spleen of QP-clone-bearing mice 21 days after the inoculation of tumors, whereas the spleen cells of QR-clone-inoculated mice retained their CTL activity. We determined that the mechanism responsible for the regression of these regressor clones is not due to any qualitative or quantitative increase in pre-existing membrane antigens, nor the emergence of new antigen(s) on the cell surface of the QR clones: nor was it due to enhanced susceptibility of QR clones to natural killer cells, lymphokine-activated killer cells and macrophages. These finding suggest that the regression mechanism of QR clones may be the diminished inhibition of host response to tumor-associated antigen caused by the reduced production of PGE2 by QR clones.

Failure of specific adoptive immunotherapy owing to survival and outgrowth of variant cells

Adoptive immunotherapy, the transfer of spleen cells from immunized mice to mice with a small tumor, was usually curative for mice with the P815 mastocytoma provided that steps were taken to prevent the generation of tumor-induced suppressor cells in the recipient animal. However, failure of adoptive immunotherapy of the P815 tumor, resulting in regrowth of either the primary intradermal or a metastatic tumor, was observed in 10 out of 112 animals receiving graded doses of 7.5 x 10(7) to 3.0 x 10(8) immune spleen cells. Examination of the ten tumors in mice that failed to respond to therapy revealed that seven of them were significantly less susceptible than the original P815 tumor to rejection in vivo by transferred anti-P815-specific effector cells. In addition, nine of the ten therapy-failure tumors were also less susceptible than the original P815 tumor to lysis in vitro by P815-specific, but not DBA/2-specific, cytotoxic T lymphocytes. Sensitivity to lysis by tumor-specific cytotoxic T cells was not, however, strongly correlated with sensitivity to rejection in vivo by P815-specific effector spleen cells. Neither in vivo sensitivity to rejection, nor sensitivity to cytotoxic T cells, was correlated with alterations in class I major histocompatibility complex antigen expression. These results suggest that the survival and outgrowth of variant tumor cells was frequently the cause of failure of specific adoptive immunotherapy of the P815 tumor, and that selection for cells with a reduced sensitivity to killing by cytotoxic T cells was only one mechanism that might lead to an immunotherapeutic failure.

Augmentation of host antitumor immunity by low doses of cyclophosphamide and mafosfamide in two animal tumor models

By cloning in vitro we have obtained two sublines of the L5222 rat leukemia, one with high (L5222-S) and the other with low (L5222-R) in vivo sensitivities to non-toxic doses of mafosfamide, a stabilized derivative of 4-hydroxy-cyclophosphamide. This sensitivity in vivo was not related to the cytotoxic activity of the drug in vitro. Treatment of rats bearing the L5222-S and of mice transplanted with the MOPC-315 plasmocytoma with low doses of mafosfamide or cyclophosphamide resulted in a high percentage of surviving animals, which were resistant to a subsequent tumor challenge. Viable leukemic cells were needed to establish antitumor immunity, since it was not possible to induce resistance by injection of mitomycin-C-treated, non-viable L5222 cells. The adoptive transfer of spleen cells from animals immune against the L5222-S and the MOPC-315 resulted in resistance of the syngeneic recipients against a rechallenge with tumor cells, provided that the animals were treated with an immunosuppressive dose (100 mg/kg) of cyclophosphamide prior to the spleen cell implantation. In nude mice treatment of the L5222 with low doses of mafosfamide also resulted in surviving animals, however resistance to a second tumor challenge occurred only sporadically. The data presented confirm that therapy with cyclophosphamide or mafosfamide enhances host antitumor immunity but, contrary to previous reports, it could be demonstrated that successful tumor rejection was independent of T cells.

Influence of the donors' clinical status on in vitro and in vivo tumor-cytotoxic activation of interleukin-2-exposed lymphocytes and their circulation in different organs

In-vitro-generated lymphokine-activated killer (LAK) cells of BALB/c mice, bearing the syngeneic colon carcinoma C-26 for 7 days, were as efficient as those from normal mice in lysing C-26 cells whereas LAK cells from 14-day tumor-bearing and 5- and 14-day tumor-resected animals had a lower C-26 cytotoxicity. The level of C-26 lysis returned to normal values 30 days after surgery. To identify the best source of LAK cells in vivo, groups of normal mice were treated with 10(4), 3 x 10(4) or 10(5) U/day of interleukin 2 (EL-2) for 7 days intraperitoneally (i.p.) or intravenously (i.v.) (3 x 10(4) dose only). The highest lysis on C-26 was obtained from peritoneal exudate cells of mice given 3 x 10(4) and 10(5) U whereas spleen cells were lytic only when taken from mice treated with 10(5) U IL-2. Peripheral blood lymphocytes lacked any cytotoxicity except for the group of mice which received IL-2 i.v. The kinetics of in vivo LAK activation in different organs showed a peak of anti-(C-26) lytic activity at day 5 in peritoneal exudate cells and spleen cells of mice given IL-2 for 5 days whereas administration of LAK cells alone had no effect: IL-2 plus LAK cells gave a lower peak of LAK activity as compared with IL-2 alone. A lower level of in vivo LAK activation was found in mice whose tumor was resected 5 days before; such impairment was evident even 14 days after surgery. Homing experiments were carried out with i.v. injected 51Cr-labelled LAK cells in normal or tumor-resected mice. In normal mice the highest radioactivity at 30 min was found in the lungs; liver and spleen also showed high radioactivity whereas blood had a negligible amount of radioactivity. Radioactivity declined rapidly in lungs (less than 10% after 24 h) while remaining at appreciable levels in the liver after 24 h and 48 h; spleen showed constant levels of 12%-15%. Homing of LAK cells was altered in mice receiving IL-2 i.p. for 5 days with slower and lower radioactivity peaks in the lung and higher levels in liver. In tumor-excised mice lower levels of radioactivity were found in lungs. These results show that: (a) alterations in LAK activity occur in early-tumor-resected and large-tumor-bearing animals; (b) the route of IL-2 administration is critical in LAK activation in vivo; (c) treatment with IL-2 modifies LAK homing.

Deficiency in immunocompetence of mice cured from large MOPC-315 plasmacytomas by melphalan therapy

Mice cured from large MOPC-315 tumors by a single dose of melphalan, 7.5 mg/kg, were examined for up to 60 days after the drug treatment (71 days after the tumor inoculation) for their ability to respond to mitogenic stimulation, specific and nonspecific antigenic stimulation and for their susceptibility to inoculation with an unrelated tumor, L10 lymphoma. The response of spleen cells from cured mice to mitogenic stimulation by phytohemagglutinin or concanavalin A was slightly depressed at an early stage after the drug treatment. The allogeneic response against C57BL spleen cells and the antibody response against sheep red blood cells (SRBC) of spleen cells from cured mice remained below normal levels during the whole observation period. The deficiency in response to antigenic stimulation was found to be due to impairment in T-cell function. Cured mice were also deficient in their response to SRBC immunization (antibody and delayed-type hypersensitivity responses) and were more susceptible to inoculation with an unrelated tumor, L10 lymphoma, than normal, noninoculated mice. On the other hand, spleen cells of cured mice developed a highly specific cytotoxic response against target MOPC-315 tumor cells and the cured mice were resistant to challenge with an otherwise highly tumorigenic dose of MOPC-315. Thus, cured mice remained deficient for a long period of time in their response to MOPC-315-unrelated antigens but, at the same time, they showed a potent specific antitumor immunity potential in vivo and in vitro.

Synergistic induction of lymphokine (IL-2)-activated killer activity by IL-2 and the polysaccharide lentinan, and therapy of spontaneous pulmonary metastases

Spleen cells of C57BL/6N mice bearing lung metastases were induced to the cytotoxic state by subcutaneous injection of recombinant human interleukin-2 (IL-2) at a minimum dose of 5 x 10(4) U/mouse three times a day for 3 consecutive days. A single intraperitoneal injection of lentinan alone at concentrations of up to 10 mg/kg body weight did not render spleen cells cytotoxic to P-29 cells, but a combination of subthreshold doses of these agents (5 x 10(4) U/ml IL-2 and 5 mg/kg lentinan) induced significant in vivo lymphokine-activated killer activity in spleen cells of tumor-bearing mice. Similarly, spleen cells from mice treated i.p. with lentinan became cytotoxic on in vitro treatment with IL-2. The in vitro responsiveness of spleen cells to IL-2 was maximal 3 days after i.p. injection of lentinan. Synergism between IL-2 and lentinan was also observed in mice bearing spontaneous lung micrometastases: neither IL-2 (less than 5 x 10(4) U/mouse) nor lentinan (less than 2.5 mg/kg) alone had a therapeutic effect, but multiple injections of IL-2 with a single injection of lentinan resulted in significant inhibition of spontaneous pulmonary metastases. From these results we conclude that IL-2 and lentinan in combination are more effective than either one alone for inducing destruction of pulmonary metastases.

Modification of tumor cells by a low dose of Newcastle disease virus. II. Augmented tumor-specific T cell response as a result of CD4+ and CD8+ immune T cell cooperation

Augmented tumor-specific T cell responses were observed against the high metastatic murine lymphoma variant ESb when using as immunogen ESb tumor cells that had been modified by infection with a low dose of Newcastle disease virus (NDV). Such virus-modified inactivated tumor cells (ESb-NDV) were potent tumor vaccines when applied postoperatively for active specific immunotherapy of ESb metastases. We demonstrate here that immune spleen cells from mice immunized with ESb-NDV contain enhanced immune capacity in both the CD4+, CD8- and the CD4-, CD8+ T cell compartments to mount a secondary-tumor-specific cytotoxic T cell response in comparison with immune cells from mice immunized with ESb. ESb-NDV immune CD4+, CD8- helper T cells also produced more interleukin 2 after antigen stimulation than the corresponding ESb immune cells. There was no participation of either CD4+ or CD8+ virus-specific cells in the augmented response. The specificity of the T cells for the tumor-associated antigen remained unchanged. Thus, there is the paradox that the virus-mediated augmentation of the tumor-specific T cell response in this system involves increased T helper activity but does not involve the recognition of viral epitopes as potential new helper determinants.

Role of interleukin-2 and interferon-gamma in induction of activated natural killer cells from mice primed in vivo and subsequently challenged in vitro with the streptococcal preparation OK432

The natural-killer(NK)-cell-mediated cytotoxicity to syngeneic tumor cells can be augmented by in vivo priming and subsequent in vitro challenge with the streptococcal preparation OK432. Supernatants of cocultures of spleen cells with OK432 contained interleukin-2 (IL-2) and interferon (IFN), mainly IFN-gamma. As the anti-(mouse IFN-gamma) monoclonal antibody but not anti-(mouse IFN-alpha) antibody inhibited the induction of activated NK cells with OK432, the IFN-gamma participated in this response. The enhancement of NK cell activity and production of IL-2 were partially inhibited by the pretreatment of spleen cells with mitomycin C or irradiation, and were completely abolished by pretreatment with actinomycin D. The IL-2 activity after treatment with various metabolic inhibitors ran parallel to the NK activity in a system augmented with OK432. The activity of incubated spleen cells with IL-2 receptors was increased by OK432 treatment, and the NK cell and IFN activities of supernatants were also abrogated by the treatment with anti-(mouse IL-2 receptor) monoclonal antibody, to block the interaction between IL-2 and these receptors of effector cells. The panning method clarified that the incubated spleen cells with IL-2 receptors are responsible for the production of IFN-gamma. These results suggest that IL-2 plays a major role in inducing the activated NK cells from murine spleen cells primed in vivo and subsequently challenged in vitro with OK432, by the production of IFN-gamma.

Induction by an immunogenic immunomodulating agent of nonspecific T cell suppression of lymphocyte responsiveness in MLR but not of antibody production

Spleen cells derived from BALB/c mice that had been repeatedly immunized with the methanol extraction residue (MER) fraction of tubercle bacilli exhibited a depressed capacity to act as responder cells in allogeneic and syngeneic mixed lymphocyte reactions (MLR). Previously reported studies revealed that such spleen cells are also defective in the in vitro generation of antibodies. In order to determine the nature of the cells responsible for the depressed MLR reactivity, purified populations of splenic macrophages, B lymphocytes, T lymphocytes originating from normal and from MER-immunized mice, and cell culture supernatants were added to MLR mixtures consisting of normal mouse splenocytes. Macrophages originating from MER-immunized mice and their culture supernatants exerted a significantly higher suppressive effect on MLR than that of corresponding preparations from normal mice. Splenic T cells originating from MER-immunized mice and their supernatants also significantly suppressed the MLR response. However, the same T cell populations that were inhibitory in MLR failed to suppress the in vitro generation of antibodies against sheep red blood cells in the presence of either MER or 2-mercaptoethanol. These and previously reported findings indicate that a nonspecific immunomodulating agent, MER, can, under certain conditions of treatment, elicit the induction of nonspecific suppressor T cells for MLR but not for antibody production, and, accordingly, can inhibit cellular and humoral immunological responsiveness by different mechanisms.

Effect of low-dose cyclophosphamide therapy on specific and nonspecific T cell-dependent immune responses of spleen cells from mice bearing large MOPC-315 plasmacytomas

Some T cell-dependent immune parameters were examined in mice bearing a large MOPC-315 plasmacytoma before and after treatment with a low dose (15 mg/kg) of CY. Prior to CY therapy, spleen cells from mice bearing a large MOPC-315 tumor were depressed in their ability to generate an in vitro cytotoxic response to the MOPC-315 tumor, to a different syngeneic plasmacytoma, MOPC-104E, and to an allogeneic thymoma, EL4. The spleen cells of these mice were also depressed in their ability to proliferate in response to the T cell mitogen PHA. Following CY therapy, the spleen cells generated an enhanced anti-MOPC-315 cytotoxic response by day 2, and the level of this response continued to increase so that by day 7, it was greatly enhanced and was much greater than the response of normal spleen cells. The recovery of the cytotoxic responsiveness to the antigenically related MOPC-104E tumor after CY therapy followed a similar pattern. In contrast, the spleen cells of these animals remained depressed in their cytotoxic response to the antigenically unrelated EL4 thymoma for at least 11 days after CY therapy. Although the anti-EL4 response recovered by day 14, the level of antitumor cytotoxicity generated did not exceed that generated by normal spleen cells. The PHA response remained greatly depressed in CY-treated MOPC-315 tumor bearers, even 14 days after the chemotherapy. Thus, at a time following low-dose CY therapy, when potent T cell-dependent antiplasmacytoma immunity had completed the eradication of a large MOPC-315 tumor burden not eliminated through the direct effect of the drug, the T cell-dependent response to an unrelated tumor and to PHA remained depressed.

Lymphocyte-induced angiogenesis factor is produced by L3T4+ murine T lymphocytes, and its production declines with age

Lymphocyte-induced angiogenesis factor (LIA) is a product of T lymphocytes which has been shown to stimulate new vessel formation. Because immune senescence most profoundly affects T lymphocyte functions, we suspected that LIA production would decline with age. An assay for angiogenesis stimulated by allogeneic reaction was performed by injecting spleen cells from young or old donor mice into the skin of irradiated allogeneic recipient mice. The spleen cells from young mice induced a significantly greater number of vessels than did cells from older mice. In additional experiments, spleen cells from young and old animals were treated with a monoclonal antibody GK 1.5) directed at the L3T4 antigen on murine T helper lymphocytes. Such treatment significantly reduced the new vessel formation induced by young lymphocytes but had no effect on that induced by lymphocytes from old animals. Studies employing indirect immunofluorescence demonstrated that the proportion of L3T4+ cells in the mononuclear fraction of splenocytes was nearly identical in both young and old mice. From these investigations we can conclude that (1) L3T4+ lymphocytes are responsible for LIA production, and (2) production, like that of other T lymphokines, declines with age.

The immunological mouse mutants nude (nu) and rhino (hrrh) generate cytotoxic effector cells following adoptive immunotherapy but fail to reject a transplanted tumor

Adoptive immunotherapy, consisting of cyclophosphamide injection and the i.v. transfer of tumor-sensitized T cells, resulted in rejection of the immunogenic fibrosarcoma, MCA/76-9, by syngeneic C57BL/6J (B6) mice. The same treatment of tumor-bearing congenic immunodeficient mice, homozygous for the deleterious mutations nude (nu) and rhino (hrrh), did not result in tumor rejection. Paradoxically, the intratumor and intrasplenic changes taking place in each of the three strains after therapy were indistinguishable. There was an increase in Thy-1+, Ly-2+, or L3T4+ cells at the tumor site 8 days after adoptive immunotherapy and a similar increase in Thy-1+ cells in the spleen. Moreover, the T cells isolated from the tumors or spleens from each genotype were shown to be specifically cytotoxic in vitro as well as in an in vivo Winn assay. Further evidence that immune amplification had occurred in the immunological mutant mice was provided by experiments showing (a) the ability of spleen cells from tumor-bearers and those tested after therapy to produce IL-2 in response to Con A stimulation and (b) an increase in class II-MHC antigen expression by tumor-associated macrophages. The data suggest that, although amplification of antitumor immune responses occurred in the immunological mutants, the absence of a critical host factor limited the potency of the antitumor response.

Comparison of excision versus cryosurgery of an HSV-2-induced fibrosarcoma. I. Survival, extent of metastatic disease and host immunocompetence following surgery

Cryosurgery and excision were used to treat primary tumours of HSV-2-transformed hamster tumour sublines, and post-operative survival and the extent of metastatic disease were compared in the two groups. An inferior prognosis was observed following cryosurgery although the extent of metastatic disease was similar in both groups. Using this model it would appear that cryosurgery enhances the development of micrometastases rather than affecting the number of cells shed from the primary tumour during surgery. To investigate the underlying causes of the decrease in survival following cryosurgery, in vitro assays were used to monitor host immunocompetence following surgery. The results showed that whilst natural killer cell cytotoxicity was only marginally depressed, mitogen responsiveness and lymphocyte participation in a mixed lymphocyte reaction were severely reduced 3-7 days post-cryosurgery. In parallel with immunosuppression, extensive cell proliferation in the spleen of cryosurgically treated tumour-bearing animals was observed. Histological examination of the spleen demonstrated the presence of large numbers of transformed cells which correlated with the loss of mitogen responsiveness and the ability to participate in a mixed lymphocyte reaction. Further studies (manuscript submitted for publication) have demonstrated that spleen cells from animals whose tumour is treated by cryosurgery are capable of suppressing immunocompetence in vitro, implying they have a role in the uncontrolled growth of micrometastases in vivo.

Sublethal, whole-body ionizing irradiation can be tumor promotive or tumor destructive depending on the stage of development of underlying antitumor immunity

It was shown that sublethal (500 rads), whole-body gamma-irradiation of mice bearing an established i.d. immunogenic tumor can result, after several days delay, in complete tumor regression and long-term survival, but only if radiation is given after the tumor is established and growing progressively. Exposing mice to the same dose of radiation several hours after tumor cells were implanted resulted, in contrast, in enhanced growth of the primary tumor and in earlier death from systemic disease. Irradiation-induced tumor regression failed to occur in mice that were incapable of generating antitumor immunity, because of having been made T cell deficient by thymectomy and irradiation. Again, irradiation-induced tumor regression could be blocked by infusion of spleen cells from donor mice bearing a well-established tumor. These and previously published results support the view that sublethal, whole-body ionizing irradiation causes tumor regression by preferentially destroying radiosensitive suppressor T cells, thereby enabling the host to generate a therapeutic level of concomitant immunity. It is suggested that the preferential destruction of suppressor cells by irradiation depends on the acquisition, during immunologic induction, of radioresistance by antigen-activated effector T cells, and that this is the reason irradiation causes regression only of established tumors. Not all tumors tested were immunogenic enough to undergo regression in response to gamma-irradiation.

The mode of recognition of tumor antigens by noncytolytic-type antitumor T cells: role of antigen-presenting cells and their surface class I and class II H-2 molecules

The present study investigated the role of antigen-presenting cells (APC) in the activation of noncytolytic T cells against tumor antigens. The noncytolytic-type T cells exerted their antitumor effect by producing gamma-interferon (IFN-gamma) and by activating macrophages as the ultimate effectors. The production of IFN-gamma by these noncytolytic T cells following the stimulation with tumor cells required the participation of Ia+ APC, since the depletion of APC from cultures of tumor-immunized spleen cells resulted in almost complete inhibition of the IFN-gamma production. Both L3T4+ and Lyt-2+ subsets of T cells were capable of producing IFN-gamma, and the requirement of APC for the production of IFN-gamma was the case irrespective of whether noncytolytic T cells were of L3T4+ or Lyt-2+ phenotype. More importantly, it was demonstrated that the production of IFN-gamma by L3T4+ and Lyt-2+ T cells was inhibited by addition of the respective anti-class II and anti-class I H-2 antibody to cultures. These results indicate that antitumor L3T4+ or Lyt-2+ noncytolytic T cells are activated for the IFN-gamma production by recognizing tumor antigens in the context of self-class II or -class I H-2 molecules on APC.

The anti-tumour efficacy of human recombinant interleukin 2. Correlation between sensitivity of tumours to the cytolytic effect of LAK cells in vitro and their susceptibility to interleukin 2 immunotherapy in vivo

Experiments were designed to test what percentage of experimental MC-induced murine sarcomas were sensitive to the local tumour inhibitory effect of IL-2 and whether any correlation existed between the sensitivity of these sarcomas to the immunotherapeutic effect of IL-2 and their susceptibility to the cytolytic effect of IL-2-activated killer cells. It was found that the sensitivity of MC-induced sarcomas to local IL-2 immunotherapy was a general phenomenon. Repeated peri-tumoural injections of RIL-2 inhibited the growth of five (MC11, MC13, MC14, MC15, MC16) out of six sarcomas in syngeneic mice. The sixth murine sarcoma (MC12) was found to be resistant to the tumour inhibitory effect of IL-2. Similarly, five (MC11, MC13, MC14, MC15, MC16) out of six murine sarcoma cell lines were sensitive to the cytolytic effect of IL-2-activated syngeneic killer spleen cells when examined in vitro, whereas the sixth (MC12) sarcoma cell line was resistant. These results suggest that LAK cells represent the effector cell mechanism responsible for the anti-tumour efficacy of local IL-2 immunotherapy and that in vitro testing of sensitivity to the LAK cell-mediated cytolysis may be used to detect tumours responding to IL-2 immunotherapy in vivo.

Enhancement of interleukin-2 release in rats by treatment with bleomycin and adriamycin in vivo

Spleen cells from rats previously injected with bleomycin (10 mg/kg) or Adriamycin (1 mg/kg) were able to release higher levels of interleukin-2 (IL-2) than cells from untreated animals. The difference in IL-2 release was detected after the cells were exposed to a suboptimal dose of concanavalin A (0.5 micrograms/ml) for 24 h. By cytofluorimetry, these drugs did not change the proportion of W3/25+ (helper) or OX-8+ (suppressor) T-cell subsets. In contrast, the immunosuppressive drug cyclophosphamide inhibited the IL-2 release from spleen cells under the same conditions. It is suggested that some anti-cancer antibiotics may be able to enhance the release of IL-2 while other cytotoxic drugs with more immunosuppressive potential could inhibit the release of this mediator.

In vitro and in vivo release of cytostatic factors from Lactobacillus casei-elicited peritoneal macrophages after stimulation with tumor cells and immunostimulants

The effect of tumor cells and immunostimulants on the release of cytostatic factors (CF) from Lactobacillus casei YIT 9018 (LC)-, Corynebacterium parvum (CP)- or peptone-elicited peritoneal macrophages (PM) was investigated in vitro and in vivo. Significant release of CF into the culture medium from PM elicited with LC was induced by seven of eight mitomycin C-pretreated tumor cell lines and not by normal spleen cells, while no CF was released extracellularly from peptone-elicited PM given the same stimulus. CF were released from LC-elicited PM (LCEPM) after stimulation with LC, bacille Calmette-Guérin, streptococcal preparation OK-432, fucoidan or lipopolysaccharide, and LC but not CP induced CF production in the peritoneal cavities of LC- or CP-primed mice. The release of CF from LCEPM after stimulation with mitomycin C-pretreated 3T12-3 cells was inhibited by D-mannose and not by L-fucose. L-Rhamnose and mannose 6-phosphate, but not D-mannose or L-fucose, caused the release of CF from the PM. It was suggested that the release of CF from activated PM is caused by stimulation by some tumor cells, sugars, or bacterial immunostimulants, D-Mannose and L-rhamnose on the surface of tumor cells or bacteria, respectively, may plan an important role in the release of CF from activated macrophages.

Studies on the recovery from tolerance to tumor antigens. I. Bone marrow cells from tolerant hosts are not rendered tolerant, but provide potential to reconstitute tumor-specific effector T cell clones

The present study investigates the potential of bone marrow cells from mice tolerant to tumor antigens to repopulate tumor-specific effector T cells. C3H/He mice were inoculated i.v. with 10(6) 10,000 R X-irradiated syngeneic X5563 plasmacytoma tumor cells three times at 4-day intervals. This regimen abrogated the ability of spleen cells from these mice to develop anti-X5563 cytotoxic and in vivo protective (tumor-neutralizing) T cell-mediated immunity as induced by i.d. inoculation of viable X5563 cells followed by surgical resection of the tumor. Since such suppression was induced in a tumor-specific way, this represented a state of antitumor tolerance. When bone marrow cells from normal or X5563-tolerant mice were transferred i.v. into 950 R X-irradiated syngeneic C3H/He mice, both groups of recipient mice generated anti-X5563 tumor immunity over a similar time course and to almost the same degree. Anti-X5563 tumor immunity induced in (C3H/He X C57BL/6) F1 mice which had been transferred with bone marrow cells from normal or X5563-tolerant C3H/He mice were mediated by T cells expressing the Ly phenotype of C3H/He, but not of C57BL/6, excluding the possibility that the antitumor effector cells were derived from recipient mice. It was also demonstrated that C3H/He mice which had been reconstituted with normal marrow were rendered tolerant when the tolerance regimen was started 7 weeks, but not 1 week after the bone marrow reconstitution. These results indicate that bone marrow cells from antitumor tolerant mice are not rendered tolerant to the tumor but can provide the potential to repopulate antitumor CTL and in vivo protective effector T cells.

Defective T helper activity in the spleen of BALB/c mice immune to a syngeneic fibrosarcoma

BALB/c mice were immunized with the syngeneic 3-methylcholanthrene-induced fibrosarcoma CA-2 by the growth and excision method. When lymphoid cells from different organs of these tumor-free mice were tested in a direct 51Cr-release assay, peritoneal exudate cells but not spleen cells displayed specific cytotoxicity against the syngeneic tumor target. A cytotoxic response could be obtained by tumor-immune spleen cells when cultured in a mixed lymphocyte tumor cell culture (MLTC) at high but not low density although at the same effector/stimulator ratio. Lack of cytotoxic activity in low density MLTC was not due to an impairment of cytotoxic precursors since cytotoxicity was rescued by adding exogenous interleukin-2 in experimental conditions in which no lymphokine-activated killer cells could develop relevant anti-CA-2 lysis. When low density MLTC were supplemented with either 800 R-irradiated cells or nonirradiated, negatively selected Lyt 1+ cells from the same immune mice, induction of a cytotoxic response against CA-2 occurred and interleukin-2 production became detectable. Additional studies indicated that spleen cells of CA-2-immune mice were also impaired in their ability to provide help to syngeneic thymocytes for the generation of cytotoxic T lymphocytes against C57BL/6J alloantigens. Dilution effect of helper cells due to immunization procedures was excluded since spleen cells of mice immunized against another BALB/c tumor, the YC8 lymphoma, or against DBA/2 minor histocompatibility antigens provided good help to thymocytes against the same alloantigens. These results indicate that tumor-immune animals may also have selective T helper defects in an important lymphoid organ like spleen.

Cultivation of avian rotaviruses in chicken lymphocytes and lymphoblastoid cell lines

Avian rotavirus isolates were used to infect normal chicken spleen cells, lymphoblastoid T cell lines transformed by Marek's disease virus, an avian leukosis virus-transformed B cell line, and a reticuloendotheliosis virus-transformed line, which is a pre-B, pre-T cell line. All five isolates tested were able to infect spleen cells and the three types of lymphoblastoid cell lines, suggesting that avian rotaviruses can infect both B and T cells. Splenic lymphocytes were considerably less susceptible to infection than chick kidney cells. Lymphoblastoid cell lines remained virus-positive during a 10-day culture period. Virus was neutralized by the addition of low dilutions of normal chicken serum and high dilutions of chicken anti-rotavirus serum.

Adoptive immunity in mice challenged with L1210/DTIC clones

New antigenic specificities, not detectable on parental cells, have been induced by many investigators in mouse lymphomas by treatment with the antitumor agent 5(3,3-dimethyl-1-triazeno)imidazole-4-carboxamide (DTIC). The antigens are transmissible, after withdrawal of the drug treatment, as an inheritable character. The mechanism of induction, the molecular nature, and the number of the new antigenic specificities have not been completely elucidated. Four clones from murine leukemia L1210 isolated and expanded in vitro were treated in vivo with DTIC and the new sublines were studied in detail. The four drug-treated sublines studied exhibited strong immunogenicity since they were rejected by syngeneic animals. Immunosuppressed animals challenged with 10(7) A/DTIC or P/DTIC cells were reciprocally protected by the adoptive transfer of spleen cells from donors that had rejected a lethal challenge of A/DTIC or P/DTIC clone. In a similar fashion, the adoptive transfer of spleen cells obtained from animals that had rejected the Q/DTIC or the R/DTIC clones protected immunosuppressed mice challenged with Q/DTIC or R/DTIC cells. No antitumor activity was observed in cross-protective schedules other than those indicated. It was been concluded that (a) the L1210 leukemia line does not have antigenic cells, (b) four DTIC-treated clone sublines were rejected by compatible hosts, and (c) two mutually exclusive sets of antigens were expressed in four antigenic clone sublines.

Induction of activated natural killer cells from murine spleen cells primed in vivo and subsequently challenged in vitro with the streptococcal preparation OK432

The present study shows that natural killer cell-mediated cytotoxicity of BALB/c mouse spleen cells to syngeneic tumor cells was augmented by in vivo priming or in vitro stimulation with the streptococcal preparation OK432. The augmentation of spleen cell cytotoxicity to syngeneic tumor cells by in vivo priming alone with OK432 was lower than that obtained by in vitro stimulation alone with OK432. When the murine spleen cells primed in vivo with OK432 were rechallenged in vitro with OK432 at various intervals, the natural cytotoxicity was more strongly enhanced than that seen with in vitro stimulation alone. The cell surface phenotype of killer cells activated with OK432 was Thy 1+ and asialo GM1+, suggesting the activated natural killer cell. Next, mice were transplanted with syngeneic colon adenocarcinoma cells, and primed in vivo with OK432. These spleen cells were subsequently challenged in vitro with OK432. These spleen cells displayed a strong cytotoxic activity not only to the transplanted adenocarcinoma cells but also to other syngeneic tumor cells.

Mechanism(s) of in vitro macrophage activation with Nocardia rubra cell wall skeleton: the effects on macrophage activating factor production by lymphocytes

BALB/c mouse peritoneal macrophages prepared from WPC which had been treated with N. CWS demonstrated potent cytostatic activity against syngeneic Meth A fibrosarcoma cells. The maximum cytostatic activity developed in the macrophages when WPC were incubated with 25 micrograms/ml N. CWS for 3 days. NAPC from BALB/c mice given an i.p. injection with 100 micrograms N. CWS 7 days previously (N. CWS-NAPC) or supernatants from N. CWS-NAPC also activated peritoneal macrophages in vitro. However, when peritoneal macrophages were incubated with N. CWS in the absence of NAPC, or when T cells were depleted from WPC by treatment with anti-Thy 1.2 antibody and complement, N. CWS failed to enhance the cytostatic activity of the macrophages. Furthermore, thioglycollate-elicited peritoneal macrophages from C3H/HeN mice increased their cytolytic properties by incubation with supernatant fluids from N. CWS-treated spleen cells. These findings suggest that in vitro macrophage activation with N. CWS depends on MAF secreted from T lymphocytes.

Specificity of the generation and expression of enhanced anti-plasmacytoma immunity by spleen cells from melphalan-treated MOPC-315 tumor bearers

We have shown previously that low-dose melphalan (L-PAM) therapy of mice bearing a large MOPC-315 plasmacytoma enables their hitherto immunosuppressed spleen cells to exert potent anti-MOPC-315 cytotoxicity following in vitro immunization with MOPC-315 tumor cells. Here we show that, following in vitro immunization with MOPC-315 tumor cells, spleen cells from such L-PAM-treated MOPC-315 tumor bearers exhibited enhanced T-cell-mediated cytotoxicity not only against the MOPC-315 tumor, but also against another plasmacytoma (MOPC-104E) possessing surface immunoglobulin (SIg) of a different idiotype than the MOPC-315 cells, as well as against a variant of the MOPC-315 tumor which does not produce nor possess SIg (SIg- MOPC-315). The enhanced cytotoxicity was directed against target antigens which are not expressed on the surface of the syngeneic WEHI 22.1 thymoma or the natural killer-sensitive YAC-1 cells. Plasmacytoma shared antigens, other than immunoglobulins, were able to stimulate spleen cells from L-PAM-cured MOPC-315 tumor bearers to generate in vitro a secondary type anti-plasmacytoma cytotoxic response. L-PAM-cured MOPC-315 tumor bearers exhibited in vivo immunity against SIg- MOPC-315 tumor cells, which was sufficiently triggered by the SIg- cells to bring about the rejection of a challenge of at least 100-fold the minimal lethal tumor dose of the SIg- MOPC-315 cells. Thus, SIg- MOPC-315 tumor cells present among SIg+ tumor cells in the parental MOPC-315 tumor inoculum can be eradicated in the L-PAM-treated MOPC-315 tumor bearers by the immune response to SIg+ tumor cells as well as by the immune response to SIg- tumor cells themselves.

Mouse cytomegalovirus is infectious for rats and alters lymphocyte subsets and spleen cell proliferation

The Smith strain of mouse cytomegalovirus (MCMV) was infectious for infant and mature DA strain laboratory rats as judged by development of neutralizing antibodies and specific spleen cell proliferation on stimulation with MCMV antigen. An i.p. inoculum of 10(6) PFU of MCMV was fatal for more than two-thirds of infant mice (1-7 days of age), and disseminated viral infection was documented by isolation of virus from body organs. In contrast, weanling and adult rats did not become ill as a result of infection with a larger inoculum of 10(7) PFU. However, these older MCMV infected rats did show transient reversals of T helper/suppressor cell ratios and alterations of immune cell function as detected by in vitro spleen cell proliferation assays. Seven days after MCMV infection, there was a generalized increase in 3H-thymidine incorporation by spleen cells in both resting (unstimulated) cultures and cultures exposed to mitogens (Con A, PHA, LPS) and to MCMV antigen. At 14 days, the spleen cell proliferation in the unstimulated cultures returned to normal but was depressed compared to controls in response to Con A. These observations show that laboratory rats are susceptible to MCMV infection and that asymptomatic infection may occur and cause transient alterations in lymphocyte subsets and in their reactivity to mitogens.

The difference between 5-fluorouracil and melphalan in their ability to promote antitumor immune response against MOPC-315 plasmacytoma

The anticancer chemotherapeutic drugs melphalan (L-phenylalanine mustard; L-PAM), 5-fluorouracil (5-FU), methotrexate (MTX), and daunorubicin (DAU) were tested for their toxic activity against MOPC-315 tumor cells in vitro. L-PAM, 5-FU, and DAU had a marked toxic effect whereas MTX did not affect the rate of thymidine incorporation in the tumor cells. L-PAM (7.5 mg/kg) induced permanent regression of large s.c. MOPC-315 plasmacytoma tumors, 5-FU (200-250 mg/kg) induced transient regression of MOPC-315 tumors with reappearance starting on the 6th day after the 5-FU injection and DAU (5 mg/kg) was not effective. L-PAM treatment restored the cytotoxic potential of spleen cells of tumor-bearing mice against target MOPC-315 tumor cells whereas spleen cells from tumor-bearing mice treated with 5-FU were unable to mount a cytotoxic response. L-PAM and 5-FU were also assayed for their effect in vitro on induction of suppressor T cells by ConA. L-PAM treatment in vitro markedly reduced the induction of suppressor T cells by ConA whereas 5-FU had no effect. It is suggested that anticancer chemotherapeutic drugs can be classified in "immunopromoting" (L-PAM as prototype) and "nonimmunopromoting" (5-FU as prototype) on the basis of their effect in vivo on established tumors and their effect on induction of suppressor T cells by ConA.

Immunoregulating activity of tumor-associated macrophages

In this report, we examine the antigen nonspecific immunoregulating activity of macrophages isolated from the murine methylcholanthrene-induced fibrosarcoma FSA. These cells were shown to enhance the primary anti-CRBC PFC response of whole normal spleen cells in a dose-dependent fashion. This function was associated with a subpopulation of large Ia-negative macrophages and was mediated by a soluble macrophage-derived factor that appeared to act by stimulating the proliferation and/or differentiation of antigen-reactive T cells. The relationship of this factor to previously described monokines is discussed.

The Lyt phenotype of the T cells responsible for in vivo tumor rejection in syngeneic mice

Spleen cells of BALB/c mice hyperimmunized with a transplantable methylcholanthrene-induced sarcoma Meth A (Meth A-Im-SPL) inhibited the growth of Meth A tumor in vivo in a tumor neutralizing test. Meth A-Im-SPL did not neutralize another antigenically distinct sarcoma, Meth 1, indicating that the antitumor activity is tumor specific. Lyt-1+2- cells of Meth A-Im-SPL (Im-Lyt-1+2-) were the effectors since in vitro treatment of Meth A-Im-SPL with anti-Thy 1.2 or anti-Lyt 1.2 antibody plus complement completely abrogated their neutralizing activity, whereas treatment with anti-Lyt 2.2 plus complement did not. To further confirm the effector activity of Im-Lyt-1+2- cells, T cell subpopulations were separated from Meth A-Im-SPL by the panning method. The purified Im-Lyt-1+2-, but not Im-Lyt-1+2+ cells neutralized the tumor in athymic nu/nu mice as efficiently as in +/+ mice, suggesting that the donor Im-Lyt-1+2- cells but not recipient T cells were primarily responsible for neutralizing the tumor. The present study, however, did not exclude the possible contribution of recipient T cells to the tumor neutralization and this is open to further investigation.

The augmentation of tumor-specific immunity by virus help. III. Enhanced generation of tumor-specific Lyt-1+2- T cells is responsible for augmented tumor immunity in vivo

The role of vaccinia virus-reactive helper T cells (Th) in augmenting in vivo generation of antitumor protective immunity and the Ly phenotype mediating the enhanced in vivo tumor immunity were investigated. C3H/HeN mice were inoculated i.p. with viable vaccinia virus to generate vaccinia virus-reactive Th activity. The mice were subsequently immunized i.p. with virus-infected syngeneic X5563 and MH134 tumor cells, and spleen cells from these mice were tested for in vivo tumor neutralizing activity. Immunization of virus-primed mice with virus-uninfected tumor cells and of virus-unprimed mice with virus-infected tumor cells failed to result in in vivo protective immunity. In contrast, spleen cells from mice immunized with virus-infected tumor cells subsequent to virus-priming exhibited potent tumor-specific neutralizing activities. Such an augmented generation of in vivo protective immunity was accompanied by enhanced induction of tumor-specific cytotoxic T lymphocyte (CTL) and antibody activities in X5563 and MH134 tumor systems, respectively. However, analysis of the effector cell type responsible for in vivo tumor neutralization revealed that enhanced in vivo immunity was mediated by Lyt-1+2- T cells in both tumor systems. Moreover, the Lyt-1+2- T cells exerted their function in vivo under conditions in which anti-X5563 tumor-specific CTL or anti-MH134 tumor-specific antibody activity was not detected in recipient mice. These results indicate that augmenting the generation of a tumor-specific Lyt-1+2- T cell population is essential for enhanced tumor-specific immunity in vivo.

Immunopotentiator separated from hot water extract of the seed of Benincasa cerifera Savi (Tohgashi)

The separation and properties of a new immuno-potentiator, Benincasa cerifera mitogen (BCM) fraction, were investigated. BCM fraction was separated from hot water extract of the seed of Benincasa cerifera Savi (Tohgashi) by gel filtration using Sepharose 4B. BCM fraction is a heteropolymer consisting of uronic acid, neutral sugars, protein, and phosphorus. The proliferation and differentiation of murine B cells were markedly stimulated by BCM fraction. The in vitro development of peritoneal macrophages into antitumor macrophages was also activated by the addition of BCM fraction to cultures. BCM fraction augmented the IgM and IgG antibody responses against sheep erythrocytes (SRBC) and the induction of delayed-type footpad reaction against SRBC. The antitumor activity of BCM fraction was observed in terms of prolongation of the survival period of mice bearing Meth A fibrosarcoma. After hydrolysis with 1% acetic acid at 100 degrees C for 4 h, marked mitogenic activity was found in a precipitate composed of 29% neutral sugars, 50% uronic acid, 1% protein, and 0.1% phosphorus. The precipitate did not contain detectable amino sugar. The possibility that the biological activities of BCM fraction may be due to contamination by bacterial lipopolysaccharide was ruled out on the basis of the results of chemical analysis and of marked mitogenicity noted in C3H/HeJ spleen cell cultures.

Effect of melphalan in vitro on induction of murine suppressor T cells by ConA

The effect of treatment with melphalan in vitro on the activity of spleen cells from BALB/c mice was investigated. Incubation of spleen cells with 1.5-5 micrograms melphalan/1 X 10(7) inhibited subsequent mitogenic stimulation by ConA or PHA and the allogeneic response of BALB/c spleen cells against C57B1 target spleen cells. Incubation of spleen cells with ConA led to induction of suppressor T cells which when added to fresh cultures inhibited the allogeneic response. Preincubation of spleen cells with melphalan even at low concentrations (0.15-0.5 micrograms 1 X 10(7) cells) which do not directly affect mitogenic stimulation or allogeneic response partially inhibited the generation of suppressor T cells by ConA. Treatment with melphalan had no effect on already induced suppressor T cells as shown by incubation of spleen cells with melphalan (0.15-5 micrograms/1 X 10(7) cells) after incubation with ConA. Addition of cells treated with melphalan alone (without ConA) to fresh cultures led to an increase in the allogeneic response.

Effects of the removal of adherent and phagocytic cells on the spleen cell lymphoproliferative response of tumor-bearing mice

Cell-mediated immunity was investigated in two BALB/c mouse tumor systems using the lymphoblastogenesis test with phytohemagglutinin as the mitogen. This lymphoproliferative response was quantitated using the Stimulation Index (SI). There was little evidence for suppressor cell activity in cell mixing experiments in which spleen cells from #51 cell-injected mice were mixed with spleen cells from normal mice. Following macrophage removal by Sephadex G-10 columns and carbonyl iron ingestion, there were no significant changes in the SI values for spleen cells from the #51 cell-injected mice. In contrast, spleen cells from mice injected with H238 cells, a herpes virus-transformed cell line, had a significantly lower SI value than that of normal mice. Suppressor cell activity was demonstrated in cell mixing experiments in which spleen cells from H238 cell-injected mice were mixed with normal spleen cells. Removal of adherent cells from spleen cells from H238 cell-injected mice by Sephadex G-10 columns restored the SI value to that of normal mice. An increased SI value was also seen after removal of phagocytic cells by carbonyl iron. These results suggested that cells with the functional properties of macrophages played an important part in the immunosuppression observed in the H238 tumor system. Comparison of the two macrophage depletion methods suggested that another cell population was also involved in the suppressive effect. Results of immunofluorescent techniques with anti-Lyt-1 and anti-Lyt-2 monoclonal antibodies show these cells to be Ly 1-, Ly 2,3+ phenotypes of T-lymphocytes.

Tumour necrosis factor and the lysosomal enzymes of macrophages or macrophage-like cell line

The relationship between tumour necrosis factor (TNF) and macrophages or macrophage-like cell line, especially the lysosomal enzymes was investigated. The serum lysosomal enzymes and LDH activities were increased in proportion to the TNF production even in different strains of mice. Lysosomal enzymes and TNF activity were released into the supernatant of the culture medium of macrophage-enriched peritoneal exudate cells (PEC) or spleen cells derived from Propionibacterium acnes-primed mice after addition of lipopolysaccharide (LPS). After passage through a Sephadex G-10 column, TNF activity could not be detected in the supernatant of these spleen cells after addition of LPS. Also TNF activity could not be detected in the supernatant following destruction of PEC. These results suggest that TNF producibility is strongly related to the degree of activation of macrophages, especially the lysosomal enzymes. The murine macrophage-like cell line, J774, also released TNF activity and lysosomal enzymes after addition of LPS.

Effect of a thymic factor, thymostimulin, on growth and pulmonary metastases of Lewis lung carcinoma

The antitumor and antimetastatic activities of a thymic factor, thymostimulin (TP-1), with or without cyclophosphamide (CPA) were examined in C57BL/6 mice inoculated with Lewis lung carcinoma (3LL). Tumor growth was followed by determining the tumor diameter after tumor implantation. TP-1 given to mice every 2 days after tumor implantation significantly inhibited tumor growth without affecting the survival rate. For induction of spontaneous pulmonary metastases, 3LL cells were implanted into the footpads of mice, and the implanted tumor was removed on day 9. The antimetastatic effect of TP-1 on pulmonary metastases after removal of the primary tumor was evaluated by counting the number of pulmonary surface nodules. TP-1 showed antimetastatic activity depending on its time of administration and dose. Combined therapy with TP-1 plus CPA significantly prolonged the survival of mice with pulmonary metastases. The cytolytic activities of spleen cells on 3LL cells were enhanced in mice treated with TP-1 and/or CPA and the cytolytic activity of nonadherent spleen cells, the T-cell population, was enhanced. The role of cytolytic spleen cells in inhibiting and preventing metastases was discussed.

Monoclonal antibodies to antigens associated with transitional cell carcinoma of the human urinary bladder. I. Determination of the selectivity of six antibodies by cell ELISA and immunofluorescence

Spleen cells from BALB/c mice immunized with cells derived from transitional cell carcinomas (TCC) of the human urinary bladder were fused with mouse myeloma Sp 2/0 Ag14 cells. Monoclonal antibodies from six established hybridomas were investigated for specificity in a cell ELISA and in indirect immunofluorescence against a large panel of fixed intact cells. Three of the antibodies reacted with half or more of the eight bladder tumors and with a few unrelated tumors. They did not react at all with malignant or normal cells of hematopoietic origin. A fourth antibody reacted with seven of eight bladder tumors. It also reacted weakly with a prostatic carcinoma, with five of six malignant or transformed B cell lines, and with a subpopulation of normal lymphocytes, but not with any of the other cells on the test panel. These four antibodies did not react with cells derived from normal urothelium. The results suggest that these antibodies might recognize cell-type-restricted antigens associated with malignancy. Another antibody reacted with almost all urothelium-derived cells. It also reacted with three of three melanomas but not with any other cells on the panel. The sixth antibody reacted with 32 of the 37 cells tested. The spectrum of reactivities displayed by the antibody suggested that it recognizes HLA antigens.