Immunomodulatory gene therapy with interleukin 12 and 4-1BB ligand: long- term remission of liver metastases in a mouse model.

BACKGROUND: The success of immunomodulatory cancer therapy is frequently hampered by the transient nature of the antitumor immune response. We have shown previously in a mouse model that interleukin 12 (IL-12) generates a strong natural killer (NK) cell-mediated antitumor response and reduces liver metastases induced by a colon carcinoma cell line. However, only a small percentage of the treated animals developed the cytotoxic T-lymphocytic response required for a long-term systemic antitumor immunity. 4-1BB is a co-stimulatory molecule expressed on the surface of activated T cells. Interaction of 4-1BB with its natural ligand (4-1BBL) has been shown to amplify T-cell (especially CD8+)-mediated immunity. In this study, we investigated the effects of adenovirus-mediated gene therapy delivering both IL-12 and 4-1BBL genes on mice with hepatic metastases induced by colon cancer cells. METHODS: Syngeneic BALB/c mice received intrahepatic injection of poorly immunogenic MCA26 colon cancer cells. Various combinations of replication-defective adenoviruses expressing IL-12 and 4-1BBL genes were injected into the established liver tumors. Changes in tumor size and animal survival were then monitored. All statistical tests were two-sided. RESULTS: The long-term survival rate of mice treated with the combination of IL-12 and 4-1BBL was significantly improved over that of animals in the control group (P =.0001). In vivo depletion of NK cells or CD8+ T cells completely abolished the long-term survival advantage of the IL-12 plus 4-1BBL-treated animals (P<.002). Moreover, the systemic immunity induced by this combination treatment protected these animals against a subcutaneous challenge with parental MCA26 cells. CONCLUSION: Adenovirus-mediated transfer of IL-12 and 4-1BBL genes directly into liver tumors resulted in tumor regression that required both NK and CD8+ T cells and generated a potent, long-lasting antitumor immunity.

[Characterization of the nuclease-sensitive chromatin regions from N-nitrosodiethylamine-induced hepatoma cells]. / Kharakteristika nukleaza-chuvstvitel'nykh uchastkov khromatina kletok gepatomy, indutsirovannoi N-nitrozodiétilaminom.

Protein-DNA complexes released from chromatin of the intact rat liver and hepatoma induced by N-diethylnitrosamine during nuclease digestion have been subdivided into two groups of high and low molecular weight. Immunoreactive proteins are concentrated mainly in high molecular complexes. Immunoblotting of proteins from the nuclease-sensitive regions of normal and tumor chromatins allow distinguishing antigens of three main types: 1--antigens of nuclease-sensitive samples common both for normal and tumor cells; 2--antigens determined in tumor preparations only; 3--antigens usual for normal samples. Such differences in composition of immunogenic proteins in the nuclease-sensitive regions from the cells of the normal and malignant rat liver may be useful for investigating changes in active chromatin during chemical induction of tumors in animals.

[The level of serum thymic activity in patients with rheumatoid arthritis and systemic lupus erythematosus]. / Uroven' timicheskoi syvorotochnoi aktivnosti u bol'nykh revmatoidnym artritom i sistemnoi krasnoi volchankoi.

Thymic serum activity (TSA) has been studied in 52 healthy subjects, 48 rheumatoid arthritis patients and 17 sufferers with systemic lupus erythematosus aged from 18 to 70. TSA was compared in patients under and over 40 years. In those under 40 TSA appeared significantly inhibited, while in older subjects it did not differ from age-matched control. No correlations were reported between TSA levels and clinical characteristics. Changes in TSA levels may be related both to low content of thymic hormones and formation of inactive complexes from thymic mediators with inhibitors.

[The effect of antibodies against Ca2(+)-ATPase and its hydrophobic fragment on the activity of this enzyme and on the passive transport of Ca2(+)]. / Vliianie antitel protiv Ca2(+)-ATPazy i ee gidrofobnogo fragmenta na aktivnost' étogo fermenta i passivnyi transport Ca2(+).

It is shown that both Ca(2+)-ATPase and its hydrophobic fragment are immunogenic factors. A region between hydrophobic and hydrophilic parts of Ca(2+)-ATP-ase is immunogenic. These antibodies clearly inhibit inflow and outflow of Ca2+ through a hydrophobic fragment reconstructed into liposomes and do not influence Ca(2+)-ATPase activity.

[Immunogenic proteins of nuclease-sensitive regions of chromatin of the normal rat liver and N-nitrosodiethylamine-induced hepatoma]. / Immunogennye belki nukleaza-chuvstvitel'nykh oblastei khromatina normal'noi pecheni krys i gepatomy, indutsirovannoi N-nitrozodiétilaminom.

The localization of immunogenic proteins of chromatin in the nuclease-hypersensitive regions was investigated by means of polyclonal antibodies against the total chromatin from cells N-nitrosodiethylamine-induced hepatoma of rats and from hepatocytes. The fractions released after digestion by Ca-dependent endonuclease and by exogenous DNasa-1 were considerably enriched with immunogenic determinants. The enrichment of nuclease-hypersensitive sites of chromatin with tumour-associated antigens was observed in experiments with antihepatoma antibodies preincubated with chromatin from the normal liver cells. Higher immunoreactivity was typical of fractions obtained during Ca-dependent endonuclease segregation of the hepatoma chromatin, while products of digestion by exogenous DNasa-1 possessed higher tumour specificity.

[Immunogenic chromatin proteins of rat hepatoma induced by N-nitrosodiethylamine]. / Isseldovanie immunogennykh belkov khromatina gepatomy krys, indutsirovannoi N-nitrozodiétilaminom.

Immunoglobulins G against chromatin of N-nitrosodiethylamine-induced hepatoma of rats have been obtained. They help determining in the hepatoma tumour-associated chromatin proteins and proteins common for chromatins of the hepatoma and normal liver. Both tissue-specific and tissue-nonspecific proteins compose immunogenic chromatin proteins of the hepatoma.

[The levels of circulating immune complexes and immunoglobulins in patients with systemic lupus erythematosus and rheumatoid arthritis]. / Urovni tsirkuliruiushchikh immunnykh kompleksov i immunoglobulinov u bol'nykh sistemnoi krasnoi volchankoi i revmatoidnym artritom.

UNLABELLED: The authors studied the levels of large- and medium molecular circulating immune complexes (CIC) and immunoglobulins of main classes (Ig) in 17 patients with systemic lupus erythematosus (SLE) and 47 patients with rheumatoid arthritis (RA). RESULTS: low molecular CIC increased in 35.2% of patients with SLE and in 42.5% with RA; patients with SLE showed a significant reduction of IgA in 80.4%. The IgA/IgM ratio was significantly reduced in SLE due to the above finding. The IgA level remained unchanged in RA.

[Possibilities and prospects of multiparameter immunologic examination in the diagnosis and prognosis of rheumatoid arthritis]. / Vozmozhnosti i perspektivy mnogoparametrovogo immunologicheskogo obsledovaniia v diagnostike i prognoze revmatoidnogo artrita.

The authors have analysed data from literature and their own results concerning multiparameter examination of the patients with rheumatoid arthritis. An effort has been made to establish a correlative relationship between changes in the following immunologic values: the level of rheumatoid factor, circulating immune complexes, antibodies to streptolysin-0 and immunoglobulin G; the number of T-lymphocytes and the quantity of natural cells of the killers and the hormone regulatory activity of thymus. Positive interdependence between the presence of rheumatoid factor and that of antibodies to streptolysin-0 as well as an increase in the content of circulating hormone complexes has been determined. In view of absence of one value which is strictly specific and compulsory for rheumatoid arthritis, it is only complex investigation that allows to describe the trends in changes of the immunologic state of the patient with rheumatoid arthritis.

[Immunochemical analysis of changes in the structure of the nuclear matrix in thymocytes of irradiated rats]. / Immunokhimicheskii analiz izmenenii struktury iadernogo matriksa timotsitakh obluchennykh krys.

It was shown that reactivity of the nuclear matrix of thymocytes for antibodies against chromatin of the control and irradiated thymocytes and PDN did not change immediately and increased markedly 2 h following irradiation of rats with a dose of 10 Gy. The method of immunoblotting failed to reveal any qualitative differences in the protein content of the thymocyte nuclear matrix of the control and exposed rats.

[Postirradiation changes in the chromatin structure of thymocytes in irradiated rats]. / Postradiatsionnye izmeneniia struktury khromatina timotsitov obluchennykh krys.

In this work the antibodies were obtained against chromatin isolated from thymocytes of intact and irradiated rats (2 h after exposing to 10 Gy) and against polydeoxyribonucleotides (PDN) extracted from thymus nuclei 6 h following irradiation. All the antibodies under study reacted more readily with the chromatin obtained from the thymus of exposed rats than with the control chromatin. The complexes of DNA with the most firmly bound non-histone proteins, obtained from the three objects under study, reacted with the antibodies with equal efficiency. Thus, a higher reactivity of PDN and chromatin from thymocytes of exposed rats was associated with the decondensation of the latter leading to an increase in availability of a part of antigenic determinants. Using the immunoblotting method we failed to discover any qualitative differences in the protein composition of the chromatin from control and exposed rats.

Immunochemical study of chromatin non-histone proteins. I. Production of antibodies against rat thymus and liver chromatin; analysis of tissue specificity and intranuclear distribution of immunogenic proteins.

Rabbit antibodies against rat thymus and liver chromatin are obtained. Antithymus IgG are found to interact only with homologous chromatin, while antiliver IgG interact with both liver and thymus chromatin. After preincubation of antiliver IgG with thymus chromatin the antibodies interact with homologous chromatin only. Thus chromatin of both organs contains tissue-specific proteins. Antiliver and antithymus IgG are used to investigate a distribution of tissue-specific and tissue-non-specific immunogenic proteins in thymocyte nuclei. It is shown that these proteins are practically lacking in nuclear membranes, matrix, nuclear sap, nucleous chromatin and do not participate in attaching DNA to the nuclear matrix.

[Localization of antigens in the chromatin of normal rat liver cells, not detectable in hepatoma chromatin]. / Lokalizatsiia v khromatine kletok normal'noi pecheni krys antigenov, ne vyiavliaemykh v khromatine gepatom.

Antibodies against rat liver chromatin interact with homologous chromatin as well as with chromatin of Zajdela ascite hepatoma and solid hepatoma 27, but not with the nuclear matrix isolated from these hepatomas. Rat liver chromatin regions hypersensitive to DNAase I and endogenous Mg2+-dependent nuclease are enriched with immunogenic nonhistone proteins. Using antiliver IgG pretreated with chromatin of Zajdela ascite hepatoma and solid hepatoma 27, it was shown that liver chromatin antigens that are not detectable in hepatoma cells are localized in hypersensitive to nucleases chromatin regions buy not in actively transcribed ones.

Immunochemical study of chromatin non-histone proteins. II. Localization of immunogenic tissue-specific proteins in nuclease-hypersensitive sites of chromatin.

Localization of immunogenic tissue-specific and tissue-non-specific non-histone proteins in thymocyte chromatin has been investigated using antibodies against rat thymus and liver chromatin. After chromatin digestion by DNAase II and subsequent fractionation with 2 mM MgCl2, the Mg2+-soluble fraction interacts with both types of antibodies 5-6 times more effectively than Mg2+-insoluble chromatin. The experiments on chromatin digestion with DNAase I indicate that tissue-specific and tissue-non-specific proteins, reacting with antibodies, are released only upon hydrolysis of the first 1-3% of DNA. Further digestion with DNAase I causes no additional solubilization of these proteins. The chromatin fraction enriched in immunogenic proteins is also released upon autolytic digestion of chromatin with endogenous nuclease. The data obtained suggest that by their function tissue-specific and tissue-non-specific antigenic determinants belong to the same class of non-histone proteins localized in the chromatin sites hypersensitive to nucleases. The possible role of these proteins in regulation of the transcription is discussed.

[Immunogenic, tissue-specific, antigenic determinants of thymocyte chromatin--firmly bound to nonhistone proteins]. / Immunogennye tkanespetsificheskie antigennye determinanty khromatina timotsitov--prochno sviazannye negistonovye belki.

Rat thymocyte chromatin was dissolved in 1.0 or 2.0 M NaCl and the dissociated proteins were separated by ultracentrifugation or gel filtration on Sephadex G-200. Rabbit antibodies against tissue-specific antigenic determinants of thymus chromatin interact with "depleted" deoxynucleoproteins and not with dissociating proteins. The DNA complex with firmly bound proteins obtained in 2 M NaCl was treated with DNAase I; this treatment had no effect on proteins interaction with antibodies. Thus, tissue-specific antigenic determinants can be related to the most firmly bound nonhistone proteins.

Chromatin regions, released by endogenous nucleases, are enriched in immunogenic tissue-specific proteins.

Localization of immunogenic tissue-specific proteins in chromatin regions, hypersensitive to endogenous nucleases, has been studied using rabbit antibodies against rat thymus chromatin. It is shown that the first 1-2,5% of the chromatin (calculating on DNA), released by Mg2+-, Mn2+- and Ca2+/Mg2+-dependent nuclear endonucleases are drastically enriched in tissue-specific antigenic determinants. The released chromatin fractions are found to contain a heterogeneous set of nonhistone proteins and are deficient in histones. The cleavage of nuclear DNA by endogenous acidic nuclease, independent on bivalent ions, resulted in a significantly less enrichment of the released fractions with immunogenic proteins.

[Differences in the antigenic structure of chromatin from the liver and hepatoma cells in the rat]. / Razlichiia v antigennoi strukture khromatina kletok pecheni i gepatom krys.

Differences in antigenic structure of chromatin from normal and tumour cells were studied using rabbit antibodies against chromatin of the rat liver, Zaidela ascite hepatoma and solid hepatoma 27 cells. It is shown that carcinogenesis is accompanied by loss of a part of normal liver antigens. All the antigens which are not indicated in solid hepatoma were not detected in ascite tumour too. The latter is deficient in some antigens common for the normal liver and solid hepatoma cells. Chromatin of both hepatomas contains antigens which are not detected in liver chromatin. Hepatoma 27 contains also antigens detected in this tumour only. At least some antigens of tumour cells are not found in regenerating liver and in liver cells of newborn rats. Antigenic properties of liver cells chromatin in old (30 months) rats approach to those of hepatoma cells chromatin.

[Intranuclear localization of hepatoma chromatin antigens not detected in liver chromatin]. / Vnutriiadernaia lokalizatsiia antigenov khromatina gepatom, ne vyiavliaemykh v khromatine kletok pecheni.

Localization of malignant cell antigens which are not detected in the liver chromatin was investigated by antibodies to chromatin of Zajdela ascite hepatoma and solid hepatoma 27. Antibodies to chromatin of Zajdela ascite hepatoma do not interact with nuclear matrix of both hepatoma and liver cells. Zajdela ascite hepatoma and solid hepatoma 27 chromatin regions hypersensitive to DNase I and endogenous Mg2+-dependent nuclease are enriched with immunogenic proteins. Antibodies to hepatoma chromatins pretreated with liver chromatin show that hepatoma chromatin antigens which are not detected in liver chromatin are localized in chromatin regions hypersensitive to nucleases but are absent (or scanty) in actively transcribed regions.

[Species specificity of immunogenic non-histone chromatin proteins from rat thymus and liver]. / Vidovaia spetsifichnost' immunogennykh negistonovykh belkov khromatina timusa i pecheni krys.

Using rabbit antibodies against rat thymus and liver chromatin, the species-specificity of immunogenic chromatin proteins was studied. The antibodies against tissue-specific and tissue-non-specific proteins of rat thymocyte chromatin are involved in criss-cross reactions with mouse thymus chromatin but do not interact with calf thymus chromatin. The antiliver immunoglobulins G interact with mouse hepatocyte chromatin, in a far lesser degree with calf liver chromatin and do not get involved in the criss-cross reactions with pigeon hepatocyte chromatin.

[Immunochemical study of non-histone proteins in chromatin regions distinguished by sensitivity to nucleases]. / Immunokhimicheskii analiz negistonovykh belkov v uchastkakh khromatina, razlichaiushchikhsia po chuvstvitel'nosti k nukleazam.

Immunization of rabbits with rat thymus chromatin induces synthesis of antibodies against tissue specific antigenic determinants preferentially. At the same time antisera against liver chromatin interact both with homologous and thymus chromatin. Antiliver IgG preincubated with thymus chromatin react with homologous chromatin only, and hence they contain antibodies against both tissue specific and tissue nonspecific antigenic determinants. We studied localization of reactive tissue specific and tissue nonspecific proteins in thymus chromatin using antibodies against liver and thymus chromatin. After chromatin digestion with DNAase II and subsequent fractionation with 2 mM MgCl2, Mg2+-soluble fraction interacts with antibodies 5-6 times more effectively than Mg2+-insoluble chromatin. Experiments on chromatin digestion with DNAase I indicate that tissue specific and tissue nonspecific proteins are released during hydrolysis of the first 1-3% DNA only. Subsequent digestion with DNAase I does not lead to additional solubilization of these proteins. The data obtained show that the investigated tissue specific and tissue nonspecific antigenic determinants belong to functionally similar non-histone proteins, which are localized in the chromatin regions hypersensitive to DNAase I. The possible role of these proteins in the regulation of transcription is discussed.