Showing papers on "BALB/c published in 1989"

Temporal development of protective cell-mediated and humoral immunity in BALB/c mice infected with Brucella abortus.

Abstract: In BALB/c mice infected i.v. with attenuated strain 19 of Brucella abortus, the organism replicates to high numbers in the spleen and reaches peak concentrations at 2 wk postinfection (p.i.). The infection is then progressively cleared so that by 8 wk p.i. numbers of bacteria have decreased 10,000 fold or more. Passive transfer assays were performed with T cell-enriched spleen cells and serum of donor mice infected 2, 3, 4, 5, 6, or 8 wk previously. Antibodies conferred significant protection to recipients at and after 3 wk p.i., whereas protection by T cells was not evident until 4 wk p.i. The combined transfer of serum and cells enhanced protection over that provided by serum or cells alone when transfers were made before, but not after, challenge infection. Protection conferred by T cell-enriched spleen cells of 6-wk donors was unaffected by the presence of equal quantities of cells from 3-wk donors, but was abrogated by the removal of both CD4 and CD8 T cell subsets. Experiments with purified CD4 and CD8 subsets revealed that cell-mediated protection resided at equivalent levels in both subsets. Daily treatment of mice with Cyclosporin A for 4 wk after infection caused some increase in numbers of brucellae in spleens and livers. Although immune responses of treated animals were markedly suppressed, there was little effect of treatment on numbers of macrophages in the spleen, on enhanced killing of Listeria monocytogenes in the spleen, or on the nature and intensity of splenic and hepatic inflammatory responses. These data indicate that acquired resistance to infection with B. abortus in mice is the result of independent, and probably also interactive, effects of antibodies and T effector cells of both CD4 and CD8 phenotypes. The initial decline in bacterial numbers in the spleen, which occurred in the absence of detectable cell-mediated immunity in that organ, could probably be ascribed principally to effects of antibodies and to nonimmune stimuli responsible for increased formation, attraction, and activation of macrophages.

Serum immunoglobulin levels and naturally occurring antibodies against carbohydrate antigens in germ‐free BALB/c mice fed chemically defined ultrafiltered diet

Abstract: This study investigates the influence of exogenous antigenic stimulation on the serum immunoglobulin levels and the levels of circulating natural antibodies against carbohydrate antigens. Thus, BALB/c mice, raised in a germ-free environment and fed a chemically defined, ultrafiltered diet (GF-CD), were employed. These mice had normal serum IgM levels, but IgG and IgA levels were approximately 5% of conventionally reared littermates. The concentrations of all four IgG isotypes were equally low. The variable part of the heavy chains of naturally occurring BALB/c antibodies against a number of carbohydrate antigens, including 3-fucosyllactosamine (3-FL), levan and dextran, are encoded by VH441, and these antibodies express cross-reactive idiotopes recognized by the monoclonal antibodies 6C4 and 6B1. Antibodies against levan and dextran were lower in GF-CD than in conventional mice, but levels of anti-3FL antibodies, and 6C4 and 6B1 idiotopes, were comparable to those in conventional animals. Peptidoglycan polysaccharide complexes (PPC) are carbohydrate antigens of bacterial origin, like levan and galactan. Naturally occurring antibodies against PPC were found in the serum of conventional mice, but were severely reduced in GF-CD mice. The results indicate that most naturally occurring antibodies against carbohydrate antigens of bacterial origin found in conventional mice are caused by exogenous stimulation.

Elimination of CD4+ suppressor T cells from susceptible BALB/c mice releases CD8+ T lymphocytes to mediate protective immunity against Leishmania.

Abstract: This study examined the capacity of BALB/c mice that had been depleted of T cell subpopulations to generate a protective immune response to Leishmania major. Thymectomized mice were depleted of either L3T4+ (CD4+) T lymphocytes, Ly2+ (CD8+) T lymphocytes, or both, by treatment with appropriate mAbs. It was found that susceptible mice were rendered resistant to Leishmania by an intravenous infusion of anti-L3T4 mAb. These mice generated an immune response that destroyed the parasite in the primary lesion and in visceral metastatic foci. CD4+ cell-depleted mice also acquired a capacity to mount a sustained delayed-type hypersensitivity (DTH) response to parasite antigens, indicating that DTH, per se, is not a disease-promoting mechanism in the susceptible murine host as has been suggested. Depleting BALB/c mice of CD8+, as well as CD4+ T cells, left them highly susceptible to Leishmania infection, thereby indicating that CD8+ lymphocytes are key protective cells. Our results can be interpreted as showing that the susceptibility of BALB/c mice is due to the generation of CD4+ cells that suppress either the generation or expression of CD8+ T cell-mediated antiLeishmania immunity.

Gamma interferon controls Eimeria vermiformis primary infection in BALB/c mice.

Abstract: Neutralization of endogenous gamma interferon by treatment with a rat monoclonal antibody caused enhancement of infection with the protozoon Eimeria vermiformis in naive BALB/c mice. The effect was dose dependent and was apparent when a monoclonal antibody was given at 2 h before infection or up to 7 days postinfection, but it decreased with increasing time postinfection between days 4 and 7. The titers of parasite-specific antibodies in the serum were not significantly affected by the injection of monoclonal antibodies. Treatment during priming did not prevent the development of resistance to challenge, and treatment at the time of challenge did not abrogate established immunity. The results indicate that gamma interferon is involved in the control of primary infection with E. vermiformis in BALB/c mice but not in the expression of immunity to challenge.

Mucosal and systemic immune responses in BALB/c mice to Bacteroides gingivalis fimbriae administered orally.

Abstract: A 41,000-molecular-weight fimbrial protein was isolated from freshly cultivated whole cells of Bacteroides gingivalis 381 and purified chromatographically. Salivary and serum antibody responses to the fimbriae, which had been orally administered in the presence of an acyl derivative of muramylpeptides, i.e., either N2-[(N-acetylmuramyl)-L-alanyl-D-isoglutaminyl]-N6-stearoyl-L-lysine [MDP-Lys(L18)] or sodium beta-N-acetyl-glucosaminyl-(1----4)-N-acetylmuramyl-L-alanyl-D-isoglu tam inyl- (L)-stearoyl-(D)-meso-2,6-diaminopimelic acid-(D)-amine-D-alanine (GM-53), or in the absence of adjuvant, were examined in BALB/c mice when administered by gastric intubation on days 0 and 1 as primary immunizations and on days 27 and 28 as booster immunizations. Gastric intubation of the fimbriae with an adjuvant significantly enhanced the production of anti-fimbria immunoglobulin A (IgA) in saliva. Subcutaneous injection of fimbriae along with an adjuvant also raised anti-fimbria IgA levels, as well as IgG levels, in saliva. Both immunization procedures enhanced the levels of anti-fimbria IgG, IgA, and IgM in serum, and the major class of fimbria-specific antibody was IgG, followed by IgA and IgM. However, subcutaneous injection was more effective than gastric intubation to enhance the production of serum antibody in mice. The subclasses of IgG antibody specific for fimbriae in serum were mainly IgG1, followed by IgG2a, IgG2b, and IgG3. These results demonstrated that the combined use of B. gingivalis fimbrial antigen and either GM-53 or MDP-Lys(L18) resulted in a sharply increased IgA antibody response in saliva and a predominantly stimulated IgG antibody response in serum, respectively. Both antibodies were found to be specific for the fimbriae used for immunization.

Immunity to larval Brugia malayi in BALB/c mice: protective immunity and inhibition of larval development.

Abstract: The objective of this study was to analyze the immune response of mice to the larval stages of Brugia malayi. Male BALB/c mice were inoculated with 3 doses of irradiated third-stage larvae (L-3) of B. malayi and were subsequently challenged with L-3 implanted ip within diffusion chambers. After 3 weeks, larvae were recovered to determine their viability, length, and stage of development. A significant reduction in parasite survival was observed in immunized mice. Furthermore, larvae recovered from immunized mice were significantly shorter than larvae recovered from control mice. All larvae recovered from immunized mice were L-3, whereas 96% of larvae recovered from controls were fourth-stage larvae (L-4). Sera collected from control and immunized mice were tested for the presence of antibodies reactive with L-3 and L-4 antigens using an indirect fluorescent antibody assay employing frozen larval cross-sections as antigen. Sera recovered after challenge of control mice reacted with internal, but not surface, antigens of L-3 and L-4. Alternatively, sera from immunized mice reacted with both internal and external antigens of both L-3 and L-4.

Mammary adenocarcinomas induced by medroxyprogesterone acetate: hormone dependence and EGF receptors of BALB/c in vivo sublines.

Abstract: Mammary adenocarcinomas were induced by medroxy-progesterone acetate (MPA) in female BALB/c mice. From 5 primary tumors, 9 different sublines were established by s.c. transplantation into syngeneic female mice; these developed after a long latent period (4-12 months). Each subline was transplanted both into 4 mice treated with 40mg of MPA depot (s.c. contralaterally to the tumor inoculum) and into 4 non-treated mice. Of the 9 sublines, 6 proved to be hormone-dependent (MPA-D) and 3 hormone-independent or autonomous (MPA-I). However, even the autonomous lines, when treated with MPA, showed a slight increase in growth. All MPA-D lines had a high content of ER (20-254 fmoles/mg of protein), PR (63-710), PRL-R (44-74) and low or non-detectable EGF-R. Of the 3 MPA-I sublines that were studied, 2 showed a high content of ER (16-125), PR (27-708), PRL-R (19-70) and EGF-R (29-65) while the other one had a low content of ER (0-36), PR (0-13), no EGF-R and moderate PRL-R (15-52). Spontaneous mammary tumors of BALB/c and C3H origin, which also showed an MPA-I pattern of tumor growth, had high levels of EGF-R. We postulate that MPA has a direct effect on mammary tumor cells in MPA-D lines and that the expression of EGF-R is correlated with an autonomous pattern of growth.

B cell repertoire in adult antigen‐free and conventional neonatal balb/c mice

Abstract: Early in ontogeny B cells preferentially use VH gene families which are most adjacent to the genes coding for the constant part of the immunoglobulin molecule. In conventional adult mice, however, a random usage of VH gene families has been found. We investigated the role of exogenous antigenic stimulation on this normalization of VH gene usage by B cells. Therefore, we made use of adult germ-free BALB/c mice fed a chemically defined ultrafiltered antigen-free diet (GF-CD) and neonatal conventional BALB/c mice. Both the adult GF-CD and the newborn conventional mice represent situations with minimal exogenous antigenic stimulation. The results obtained with RNA dot blot hybridization with probes specific for the different VH gene families showed in hybridomas from adult GF-CD BALB/c mice a preferential usage of the CH-proximal VH gene family PC7183. In hybridomas from 5-day-old conventional BALB/c mice a less frequent usage of the J558 VH gene family was found and an increased usage of the PC7183 VH gene family than what would be expected from random usage. Evidence is presented that the RNA giving a positive signal with the PC7183 probe represents functional messages for IgM production.

Mechanisms of splenic control of murine malaria: tissue culture studies of the erythropoietic interplay of spleen, bone marrow, and blood in lethal (strain 17XL) Plasmodium yoelii malaria in BALB/c mice.

Abstract: This work characterizes the erythropoietic interplay of the spleen, blood, and bone marrow in a lethal murine malaria, strain 17XL P. yoelii. This malaria runs a fulminant 7 day course in BALB/c/ByJ mice, marked by high levels of parasitized reticulocytes with death likely due to anemia. We have quantitated the levels of burst forming units-erythroid (BFU-E), the early, niche-seeking, largely erythropoietin-unresponsive erythropoietic precursors, and of colony forming units-erythroid (CFU-E), the more differentiated sessile erythropoietin-responsive precursors, in bone marrow, blood, and spleen, through the course of this malaria. A decline in marrow BFU-E began on day 2, but recovered, relatively, after day 3. Marrow cellularity declined, being but 75% normal on day 6. Spleen weight increased about 5-fold within 6 days with enlargement of erythroid, lymphoid, macrophage, and stromal compartments. Splenic BFU-E increased in the first 24 hr and 5-fold by day 6. Splenic CFU-E increased in the first 24 hr and into day 4. They then declined and showed a secondary, large-scale, sustained rise interrupted by death. Because the spleen was enlarging, a greater than 60-fold increase in the absolute number of splenic CFU-E occurred at the time of death. Marrow CFU-E followed the same pattern as splenic CFU-E, but the terminal increase represented but a 4-fold absolute increase because of declining marrow cellularity. High levels of erythropoietin occurred only late in the course of disease, likely in response to profound anemia.(ABSTRACT TRUNCATED AT 250 WORDS)

B cell repertoire in adult antigen-free and conventional neonatal BALB/c mice. II. Analysis of antigen-binding capacities in relation to VH gene usage.

Abstract: Hybridomas were derived from lipopolysaccharide-reactive splenic B cells of adult germ-free BALB/c mice fed a chemically defined ultrafiltered "antigen-free" diet (GF-CD) and from splenic B cells of 5-day-old conventional (CV-NEO) BALB/c mice. The monoclonal antibodies (mAb) from both collections of hybridomas were tested for reactivity against a large panel of antigens of exogenous and endogenous origin. As a source of natural exogenous antigens 36 different bacteria and 9 different viruses were used, while as endogenous antigens frozen tissue sections of stomach, liver and kidney, the Hep-2 cell line and the anti-idiotopic mAb Ac38 and Ac146 were used. In both collections of mAb approximately 70% reacted with one or more bacterial antigens, while no reactivity could be detected against the viral antigens. Of the GF-CD and CV-NEO hybridomas, 16% and 19%, respectively, reacted with one or more frozen tissue sections. Overall 56% and 68% of the GF-CD and CV-NEO hybridomas, respectively, were producing multireactive antibodies reactive to several exogenous and/or endogenous antigens. Among the GF-CD hybridomas a correlation was found between multireactivity and the usage of the VH gene family PC7183. In CV-NEO hybridomas, however, the preferential utilization of the VH gene family PC7183 was found among both mono- and multireactive hybridomas. The results suggest (a) that the actual B cell repertoire of neonatal mice consists of a large proportion of multireactive B cells which are reactive with autoantigens and bacterial antigens, but not viral antigens and (b) that in antigen-deprived mice the neonatal repertoire is largely preserved during maturation of the mice.

Modulation of eicosanoid production and cell-mediated cytotoxicity by dietary α-linolenic acid in BALB/c mice

Abstract: The effects of dietary α-linolenic acid (18∶3n−3) on fatty acid composition, eicosanoid production, and cell-mediated cytotoxic activity of immune cells before and after challenge with virus or poly I-C from BALB/c mice were studied. Weanling BALB/c mice were fed purified diets containing either 10%-by-weight corn oil or linseed oil providing a ratio of 18∶3n−3 to 18∶2n−6 of 1/32 or 2/1, respectively, for 6–10 weeks. Fatty acid analysis of splenocyte phospholipids showed an appreciable increase in the percentage of n−3, and a decrease in n−6, fatty acids in splenocytes from mice fed the linseed oil diet. Splenocyte prostaglandin E and peritoneal exudate cell leukotriene C production was significantly lower in the linseed oilfed mice. In general, cell-mediated cytotoxic activity was similar for immune cells from linseed oil and corn oil-fed mice. However, 6 days after the viral challenge, splenocyte cell-mediated cytotoxic activity was significantly higher in linseed oil mice. This higher activity was associated with nonspecific cytotoxicity rather than that of viral-specific cytotoxic T-lymphocytes. Cell yields from the spleen and peritoneum were frequently significantly higher in linseed oil mice. Interactions between dietary 18∶3n−3, eicosanoid production, and immune cell proliferation and/or migration are discussed. In summary, feeding mice a diet rich in 18∶3n−3 elevates immune cell n−3 fatty acid content, reduces eicosanoid synthesis and, to a limited extent, enhances the cell-mediated cytotoxic response to a viral challenge.

Combined antibody and ganciclovir treatment of murine cytomegalovirus-infected normal and immunosuppressed BALB/c mice.

Abstract: The efficacy of treatment with ganciclovir (DHPG) and antibody activity-containing ascitic fluid (AF) separately and in combination was studied in normal and immunosuppressed BALB/c mice challenged intraperitoneally with a lethal dose (10(6) PFU) of murine cytomegalovirus (CMV). With combination therapy, lower doses of both DHPG and AF were often as effective as a higher dose of either agent given singly. For instance, the survival rate of murine CMV-challenged immunosuppressed mice was doubled when 4 mg of DHPG per kg and a 1:16 dilution of AF were both administered in contrast to when each was used alone. In both groups of animals, combination therapy was shown to be more effective than either therapy individually, even when initiation of therapy was delayed as long as 48 h. Such an approach holds promise for decreasing the expense associated with antibody use and the dose-related toxicity associated with DHPG use while maintaining or possibly increasing the efficacy of prophylaxis and therapy of serious CMV disease in humans.

Blocking of lectin-like adhesion molecules on pulmonary cells inhibits lung sarcoma L-1 colonization in BALB/c-mice.

Abstract: Adhesion and inhibition experiments with pulmonary cells of BALB/c-mouse origin and syngeneic sarcoma L-1 cells indicated that L-fucose specific lectin-like adhesion molecules, presumably situated on pulmonary cell surfaces are (at least partly) responsible for the specificity of this cell-cell interaction. Addition of specific sugars and glycoconjugates (L-fucose and fucoidan, respectively) to the incubation medium evidently inhibited the adhesion process as quantified using radiolabelled tumor cells. Unspecific carbohydrates (e.g. D-galactose) did not affect the cellular interaction. In vivo, repeated administration of fucoidan (but not of unspecific glycoconjugates) significantly inhibited the settling of metastatic sarcoma L-1 cells in the lungs of BALB/c-mice. Therefore, when lectin-like adhesion molecules on pulmonary cells were blocked with competitive glycoconjugates, tumor cell colonization of the lung could be significantly inhibited.

Histopathologic study of herpes virus-induced retinitis in athymic BALB/c mice: evidence for an immunopathogenic process.

Abstract: In order to determine whether antiviral immunity is pathogenic in mouse eyes, HSV-1 was injected into the anterior chamber of one eye of adult athymic BALB/c mice. The eyes of these T cell deficient mice were examined clinically and histopathologically for ocular disease. The anterior segment of injected eyes developed progressive inflammatory reactions that eventually destroyed the ciliary body and then progressed to the posterior compartment where partial necrosis occurred, but only in the inner layers of the retina. A milder form of the same process developed between 7 and 10 days in the contralateral eye. Uninoculated eyes displayed little evidence of choroiditis, hemorrhage, massive necrosis, or disintegration of the architecture of the retina. Since these are features that are found in contralateral retinas of euthymic BALB/c mice infected in one eye via the anterior chamber route, it is concluded that acute retinitis found in contralateral eyes of immunocompetent mice has an immunopathogenic basis. However since euthymic mice develop anterior chamber associated immune deviation (ACAID) (and therefore do not display virus-specific delayed hypersensitivity), the identity of the relevant immune effector remains unknown. Based on these observations and our previous ocular findings following intracameral inoculation of HSV-2, we suggest that in susceptible mice, herpes simplex viruses can induce several pathogenetically distinct forms of retinitis, some of which are mediated by virus-specific immune effector cells.

Effect of macrophage blockade on the resistance to a primary Brugia pahangi infection of female BALB/c mice.

Abstract: Role of macrophages in the higher resistance of female BALB/c mice than males to a primary Brugia pahangi infection was investigated. Macrophage blockade by carbon injection on the day of infection or by carrageenan injection one day before infection was effective to reduce the higher resistance of females to the level of males. The timing of macrophage blockade seems to be critical because carbon treatment on day 0 or 5 post-infection (PI) was much more effective than the same treatment on day 10 PI. These results suggest that macrophages play an important role in the expression of the higher resistance of female BALB/c mice than males to a primary B. pahangi infection.

The accelerating role of Abelson murine leukemia virus in murine plasmacytoma development: in vitro infection of spleen cells generates donor-type tumors after transfer to pristane-treated BALB/c mice.

Abstract: The role of Abelson murine leukemia virus (A-MuLV) in the accelerated development of murine plasmacytomas (PCs) (Potter et al., 1973: Science, 132, 592-594) was studied in a new experimental system. Spleen cells from pristane-treated or untreated BALB/c mice carrying Robertsonian 6;15 fusion chromosomes were infected in vitro with helper-free A-MuLV overnight and subsequently transplanted into the peritoneal cavity of pristane-treated or untreated BALB/c mice. Donor-derived PCs developed in 4 out of 76 pristane-treated recipients [latent periods: 38-82 (mean 51) days] that had received spleen cells from pristane-treated donors, and also in 2 out of 41 pristane-treated recipients that had received untreated donor-derived spleen cells (latent periods: 65 and 120 days). Three of the PCs in the former and both PCs in the latter group were tested for integration and expression of the v-abl gene, with positive results. This indicates that the spleen contains PC-precursor cells that can be activated by A-MuLV even before the impact of pristane. All 6 donor-origin PCs carried a translocation involving chromosome 15, band D2/3. Four of these corresponded to a typical 12;15 translocation, one was a variant 6;15 translocation and the 6th may represent a previously unidentified translocation between chromosome 15 and the lambda gene-carrying chromosome 16. No PCs developed among 29 pristane-untreated recipients that had received pristane-treated donor-derived spleen cells. In addition to PCs, monocytic tumors developed in 37 (26%) of all recipients. Their development was independent of pristane treatment of recipients but was particularly frequent in those who had received spleen cells from pristane-treated donors.

The influence of syngeneic anti-idiotypic antibody on the biodistribution of an anti-tumour monoclonal antibody in balb/c mice

Abstract: BALB/c mice were immunized against syngeneic murine 791T/36 monoclonal antibody (MAb) by intraperitoneal (i.p.) injection of the antibody conjugated to ricin toxin A chain. Subsequently, in these and control mice, the biodistribution of radioiodinated 791T/36 antibody and isotype-matched (IgG2b) control immunoglobulin was examined. Pre-treated mice showed marked perturbation of biodistribution of the 791T/36 antibody but not of control IgG2b. This was manifest as rapid hepatic clearance of the antibody which was followed by accelerated catabolism and excretion of the radiolabel. Anti-idiotypic antibodies were identified in immunotoxin pretreated mice by their ability to inhibit the binding of FITC-labelled 791T/36 antibody to tumour target cells. These studies show that antibody responses, even to only the idiotype of a MAb, may produce marked perturbation of its biodistribution. This has implications for the clinical use of human or chimeric MAbs for tumour imaging or targeting of therapeutic agents since, if anti-idiotypic antibodies are evoked, they could still prevent tumour localization of antibody or conjugate.

Characterization of a new spontaneously developed murine mammary adenocarcinoma in syngeneic BALB/c hosts.

Abstract: A mouse mammary tumor cell line, designated JC, has been established from a spontaneously developed primary adenocarcinoma of an aged virgin female BALB/c mouse. Isoenzyme analyses including glucose-6-phosphate dehydrogenase, lactate dehydrogenase, and peptidase proved that this cell line is of murine origin and devoid of contamination from other species. Karyotyping revealed that the number of chromosome ranged from 26 to 100, with a modal number of 40. Electron microscopic examination detected the presence of tonofilament and desmosomes confirming its epithelial nature. In addition, no type B or C virus particle was detected, although intracysternal A particle was observed occasionally. Tumorigenicity in immunocompetent syngeneic hosts was easily established by s.c., i.p., and i.v. injection of viable JC tumor cells. A very weak immunogenicity of the JC tumor was demonstrated through its immunization-challenging on syngeneic immunocompetent hosts. Although no rejection of JC tumor was noted, a significant prolongation for the incubation period before an obvious and palpable tumor growth was detected between the experimental and the control animals. Development of a concomitant immunity was also detected. The JC tumor represents a valuable murine mammary tumor model which is different from other available models because of its unique origin, absence of virus particles, very weak immunogenicity, and high tumorigenicity in syngeneic hosts. The cell line has been maintained for more than 5 yr and has been used for experimental immunotherapy in our laboratory.

Vaccinia virus-infected C-C36 colon tumor cell lysates stimulate cellular responses in vitro and protect syngeneic Balb/c mice from tumor cell challenge.

Abstract: Vaccinia virus (VV) was used to infect and lyse the Balb/c colon tumor line C-C36 to prepare oncolysate (VCO) with augmented immunogenicity Mice treated with VCO and challenged with C-C36 were significantly protected against tumor growth as compared to untreated controls (P less than 0001) and mice treated with CO (P less than 001) Moreover, protection induced by VCO was specific when growth inhibition of C-C36 was compared to that of meth-A (P = 0027) Splenocytes from mice stimulated with VCO in vitro showed greater proliferation than splenocytes stimulated with CO alone or VV alone, suggesting induction of a unique VCO component Additional evidence for a specific response was suggested by the observation that splenocytes stimulated with VCO in vitro demonstrated augmented cytolysis of C-C36 but did not show cytolytic activity against unrelated target cells However, augmented cytolysis of the natural killer (NK)-sensitive YAC-1 by VCO-stimulated splenocytes was also observed These results suggest that in vivo resistance to tumor challenge induced by VCO treatment may result from stimulation of both specific and nonspecific effector cells

Cross-reacting tumor associated transplantation antigen on primary 3-methylcholanthrene-induced BALB/c sarcomas.

Abstract: Immunization of adult, syngeneic BALB/c mice with irradiated, primary MCA-induced sarcomas conferred reproducible, nonisologous TATA-associated cross-protection against challenge with other primary MCA sarcomas or in vitro passaged MCA sarcoma cells. Isologous, individually specific TSTA-associated protection was also detected. Irradiated, normal BALB/c spleen or muscle tissues were not similarly protective. Pronounced cross-protection was best detected with secondary cultured, in vitro adapted sarcoma challenge inoculum, which could be accurately standardized. These findings paralleled the good cross-protection reported previously with long-term cultured MCA-induced sarcoma cell lines. OFA was expressed as a TATA on all syngeneic, primary MCA-induced sarcomas tested by syngeneic adoptive transfer experiments and on MuLv-free MCA-induced, syngeneic Meth A sarcoma cells.

Histogenesis of dieldrin and DDT-induced hepatocellular carcinoma in BALB/c mice

Abstract: Male, Balb/c mice were fed diets containing dieldrin (10 ppm) and DDT (100-175 ppm) for 75 weeks. Control and treated mice were serially killed and their livers analyzed by histological and histochemical procedures after 2, 4, 8, 16, 36, 52 and 75 weeks of exposure. Mice administered both chlorinated hydrocarbons initially responded with centrolobular hepatocytomegaly. The cells were characterized by decreased glucose-6-phosphatase and succinate dehydrogenase activity. At later periods 52 through 75 weeks, foci of phenotypically-altered hepatocytes were noted. The cells of these lesions were basophilic or clear-staining in hematoxylin and eosin-stained sections and displayed increased gamma glutamyl transpeptidase activity. In mice preloaded with iron dextran, cells of foci were negative for iron when the surrounding parenchyma was siderotic. Hepatocellular adenomas (HA) and carcinomas (HPC) were composed of cells with increased gamma glutamyl transpeptidase and glucose-6-phosphate dehydrogenase and decreased glucose-6-phosphatase and succinate dehydrogenase activity. In iron loaded mice, the cells of HA and HPC did not stain for iron in otherwise siderotic surroundings. Both hepatocellular foci and adenomas may be potential precursors of mouse hepatocellular carcinomas.

H-2 antigens and tumour-associated transplantation antigens in clones derived from a methylcholanthrene-induced BALB/c tumour: their influence on the generation in vitro and in vivo of the specific anti-tumour immune response.

Abstract: The methylcholanthrene GR9 tumour is a fibrosarcoma, originated in a BALB/c (H-2d) mouse, composed of different clones (A7, G2, D8, D6, B11, B3, B7, C11, B10, B9) with different class I (Kd Dd Ld) expression. We present data indicating that MHC class I differences observed between the different clones correlated with RNA levels and can be modified with recombinant interferon-gamma. We also studied the presence of tumour-associated antigens in GR9 and their different clones using the monoclonal antibody (MoAb) technology. We produced two syngeneic MoAbs, A7.2 and A7.6, which reacted to GR9 clones. These MoAbs precipitated a 70-kilodalton molecule and did not react with cells positive for the classical Gp70 antigen such as YC-8, LSTRA (H-2d) and RBL-5 (H-2b) lymphomas. A7.2 and A7.6 MoAbs were also negative with normal cells. In this well-characterized tumour model, we analysed the influence of the expression of class I molecules and tumour-associated antigens upon the generation, in vitro and in vivo, of the specific anti-tumour immune response. We produced syngeneic anti-GR9 A7 cytotoxic T lymphocytes (CTLs) which showed significant cytotoxicity against most of the GR9 clones including clones with low or no H-2 class I expression. These CTLs showed no cytotoxic activity against other tumour cells and concanavalin A blasts, neither could the CTL-specific response be inhibited with A7.2 and A7.6 syngeneic MoAbs nor with a panel of anti-class I MoAbs. In vivo experiments have shown that pre-immunization with the immunogenic clone GR9 A7 protects against a challenge of the different GR9 clones, independently of their class I expression and their in vitro susceptibility to lysis by anti-GR9 A7 CTLs. These results demonstrate the existence of cross-reactive tumor-associated transplantation antigens between different clones of the same tumour and the absence of correlation between in vitro susceptibility to lysis and in vivo tumour rejection. Finally, we discuss these results in the context of anti-tumour effector mechanisms generated in chemically induced tumours.