Showing papers on "Tumor antigen published in 1979"

Radioimmunoassay for tumor-antigen of human cervical squamous cell carcinoma.

Abstract: A heterologous antiserum for human cervical squamous cell carcinoma was prepared and specificity determined by Ouchterlony immunodiffusion and immunofluoresence studies. With this antiserum, a tumor antigen was purified from human cervical squamous cell carcinoma tissue. The specificities of the antigen and the antiserum were then re‐examined by a radioimmunoassay method using 125I‐labeled purified antigen. Although normal cervical tissue extract showed a moderate cross‐reactivity in the radioimmunoassay, the circulating antigen activity could not be detected in normal women or in several patients with other carcinomas, whereas 27 of 35 patients with cervical squamous cell carcinoma showed detectable serum antigen activity. All patients with advanced stages of cervical squamous cell carcinoma showed detectable antigen levels. These results indicate that there is a quantitative abnormality, at least, of this tumor antigen in patients with cervical squamous cell carcinoma and that the radioimmunoassay for the antigen is a potentially useful tool in clinical care.

Identification and partial characterization of new antigens from simian virus 40-transformed mouse cells.

Abstract: Two new species of antigens were detected in simian virus 40-transformed mouse cells, in addition to the large (94,000 daltons) and small (20,000 daltons) tumor antigens. These antigens were immunoprecipitated from cell extracts by using anti-T serum and not normal, nonimmune serum. One of these was a protein with a molecular weight of approximately 130,000 and was present in some but not all SV40-transformed mouse cells. The other, which we have named Tau antigen, has a molecular weight of 56,000 as estimated by electrophoresis through acrylamide gels and was found in all virus-transformed cells examined. The 13,000-daltons antigen contained about 15 methionine-tryptic peptides which were also present in the large SV40 tumor antigen as determined by ion-exchange chromatography. This strongly suggested that the protein was virus coded. The 56,000-dalton Tau antigen appeared to share only two methionine-tryptic peptides with the large species of SV40 tumor antigen, as determined by ion-exchange and paper chromatographies. Our results are compatible with a cellular origin for Tau antigen. However, our data do not exclude the possibility that this protein contains sequences specified by the virus DNA.

Subcellular Localization of simian virus 40 large tumor antigen.

Abstract: The distribution of simian virus 40 large tumor antigen in subcellular fractions from simian virus 40-transformed hamster (H-50) and mouse (VLM) cells and from simian virus 40-infected monkey cells was determined. Solubilized [35S]-methionine- or 32Pi-labeled surface membrane and nuclear fractions were prepared, immunoprecipitated with hamster anti-T serum, and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Tumor antigen with an apparent molecular weight of ~96,000 was detected in both subcellular fractions. Minor components of ~68,000 and ~56,000 with anti-T reactivity which labeled with [35S]methionine were also detected in both fractions from H-50 cells, as were components of ~140,000 and ~56,000 from VLM cells. The 56,000 component appeared to be greatly reduced in 32Pi-labeled surface membrane fractions. Normal cells or cells transformed with a heterologous agent, such as polyoma virus or a chemical carcinogen, lacked immunoprecipitable tumor antigen. Cell fractionation was monitored by [3H]thymidine labeling, NADH-diaphorase activity, and Na+-K+-dependent ATPase activity. These analyses revealed only trace contamination of surface membranes by nuclei, extremely low levels of nuclear rupture during homogenization, and an approximate 10-fold enrichment of surface membrane. Reconstruction experiments demonstrated that soluble tumor antigen failed to associate or copurify with surface membranes during fractionation procedures. These results indicate the presence of a protein in the plasma membrane of cells transformed or infected by simian virus 40 that is immunologically indistinguishable from nuclear tumor antigen.

Relationship between T-antigen and tumor-specific transplantation antigen in simian virus 40-transformed cells.

Abstract: The simian virus 40 (sv40) tumor antigen (T-antigen) and tumor-specific transplantation antigen (TSTA) have been partially purified and studied to clarify their relationship. The T-antigen and the TSTA were partially purified from nuclei of SV AL/N cells, and SV40-transformed mouse embryo fibroblast line, by precipitation with ammonium sulfate and chromatography on DEAE- and DNA-cellulose. The T-antigen was assayed by complement fixation, and the TSTA was assayed by its ability to immunize mice against SV40-containing ascites tumor cells. When T-antigen- and TSTA-containing preparations were sedimented through sucrose gradients, each antigen had a major peak of activity at a sedimentation coefficient of 6.7 and minor peaks in other regions. Antiserum against T-antigen (from tumor-bearing hamsters) immunoprecipitated the TSTA activity. A preparation of T-antigen from human SV80 cells, which exhibited only one protein band after sodium dodecylsulfate-polyacrylamide gel electrophoresis, had TSTA activity when as little as 0.6 microgram of protein per mouse was used for immunization. These experiments demonstrate that the T-antigen, the product of the SV40 early A gene is capable of inducing specific immunity against transplantation of SV40-transformed tumor cells in mice.

Differential Activation of Cytotoxic and Suppressor T Cells against Syngeneic Tumors in the Mouse

Abstract: The cytotoxic T cell against a methylcholanthrene-induced sarcoma, S1509a, was induced in syngeneic mice by deliberate immunization with mitomycin C (MMC)-treated live tumor cells. The soluble tumor antigen (STA) extracted from the same tumor by 3 M KCl was, however, unable to induce the cytotoxic T cell upon immunization, although it was able to activate predominantly the suppressor T cell that then specifically suppressed the effect of the cytotoxic T cell against the homologous tumor. The suppressor T cell generated by STA had the same characteristics as those found in tumor-bearing animals: 1) The suppressor T cell has a very strict specificity against individual tumors; 2) The cell expresses cell surface determinants controlled by genes in the I-J subregion of the mouse H-2 complex. The activity of the cytotoxic T cell was completely inhibited by live tumor cells but not by STA, whereas that of the suppressor T cell was neutralized by STA. The results that cytotoxic and suppressor T cells are activated under different conditions, and that the antigenic determinants recognizable by these two cell types are not the same. The soluble extract contains only the determinants recognizable by the suppressor T cell, and the cytotoxic T cell can be activated only by the determinants associated with self antigen present on the surface of live tumor cells.

Cell-Mediated Immune Response to Syngeneic UV-Induced Tumors III. Requirement for an Ia+ Macrophage in the in Vitro Differentiation of Cytotoxic T Lymphocytes

Abstract: An Ia-positive accessory cell with macrophage characteristics was demonstrated to be required for the in vitro proliferation and differentiation of lymph node T lymphocytes from tumor-immunized mice into cytotoxic T lymphocytes (CTL). An experimental system is described that provides for the measurement of both proliferation and CTL capacity in in vitro cultures of draining lymph node (DLN) cells from tumor-immunized mice. DLN cells obtained from the popliteal lymph nodes of mice immunized in the hind footpads with a syngeneic UV-induced fibrosarcoma proliferate and differentiate into highly effective CTL (as assessed in a 6-hr chromium release assay) when placed in culture without the addition of tumor antigen. Both proliferation and CTL generation by DLN cells in vitro were shown to result from the interaction of at least two physically separable cell populations: a T cell population responsible for the proliferation and expression of CTL activity, and an accessory cell population required for the expression of the T cell functions. The accessory cell was shown to be resistant to γ-radiation, adherent to nylon and glass wool columns, sensitive to treatment with anti-Ia antisera plus complement (C), and resistant to treatment with anti Thy-1 antisera plus C. Antigen presentation did not appear to be required for effective cooperation between lymphocytes from tumor-immunized mice and accessory cells, although antigen presentation did occur when unprimed lymphocytes were mixed with accessory cells present in the DLN of tumor-immunized mice. The regulation of CTL development and the role of the Ia-positive accessory cell in anti-tumor immunity are discussed.

Regulation of immune response to tumor antigen: interference with syngeneic tumor immunity by anti-IA alloantisera

Abstract: We present evidence for a role of I-A subregion-encoded determinants in syngeneic tumor immunity. In animals rendered immune to the S1509a fibrosarcoma, daily treatment with microliter quantities of antisera directed against Kk and I-Ak determinants expressed on lymphoid cells of host origin decreased the capacity for immune tumor rejection. Absorption studies revealed that anti-I-Ak antibody activity alone was sufficient for the manifestation of this effect. Furthermore, experiments utilizing F1 hybrids showed that an antiserum that was genetically unable to interact with H-2 determinants expressed on the tumor was equally effective in inhibiting tumor immunity. Suggestive evidence that the activity of this antiserum is related to interference with the generation of effector T cell function was provided by the observation that hyperimmune animals pretreated with an anti-Kk,I-Ak antiserum were no longer capable of adoptively transferring tumor immunity to naive recipients. Thus, it is possible to regulate the secondary immune response to tumor antigens by using antisera with specificity for I-A determinants expressed on cells or possibly on factors of the host lymphoid system.

Pathogenesis of Marek's disease; effect of immunization with inactivated viral and tumor-associated antigens.

Abstract: Inactivated Marek's disease virus-infected chicken kidney cells and inactivated MSB-1 lymphoblastoid Marek's disease tumor cells were used to immunize chickens as virus- and tumor-associated antigens, respectively. Immune and nonimmune birds were then challenged by exposure to live virulent Marek's disease virus. Both vaccines protected significant numbers of chickens (P less than 0.05) against subsequent tumor development, although viral antigen appeared superior to tumor antigen. After challenge, the early appearance of viral antigen, infected lymphocytes, and degenerative changes in lymphoid organs was inhibited only by the viral antigen vaccine, whereas the early appearance of cells bearing tumor antigen was prevented by both vaccines. These results support the hypothesis that effective immunity in Marek's disease could be directed against either virus replication and spread or events associated with transformation and proliferation of lymphoid cells.

Murine natural anti-tumor antibodies. I. Rapid in vivo binding of natural antibody by tumor cells in syngeneic mice.

Abstract: A competitive radioimmunoassay (RIA) for the detection of cell-bound antibody was used to study the in vivo acquisition of immunoglobulin (Ig) by tumor cells. Several tumor lines acquired Ig rapidly between 3 and 18 h after intraperitoneal implantation into normal syngeneic mice and this Ig was recovered by elution with basic or acid buffers. The Ig eluted from the L5178Y lymphoma showed higher binding to the L5178Y than to thymocytes, bone-marrow cells, 1509a sarcoma and P-815-X2 mastocytoma. In addition, binding of the eluates to the L5178Y was specifically inhibited by L5178Y cells or by solubilized membrane antigens of the L5178Y. The in vivo acquisition of Ig by the L5178Y could also be blocked by the IV and IP injections of tumor antigen although both L5178Y and 1509a solubilized membrane antigens were effective. Some of the Ig acquired by the tumor cells was found to be complement-fixing antibody since normal rabbit complement lysed 80% of L5178Y cells obtained from the peritoneal cavity of syngeneic mice 18 h after implantation, but did not lyse in vitro L5178Y cells. The in vivo binding of the complement-fixing antibodies was also inhibited by tumor antigens in the same way as the acquisition of Ig detected by RIA. It was shown that the acquisition of Ig during the first 18h of IP growth was a T-independent phenomenon because tumor cells acquire as much Ig in AT X BM mice as in sham-thymectomized controls. In a study with 11 different clones derived from the L5178Y lymphoma, a high correlation (r = 0.75, p less than 0.005) was found between the amount of Ig acquired after in vivo implantation and the amount of Ig bound to the cells after in vitro incubation with normal syngeneic serum. It is suggested that the rapid in vivo acquisition of Ig was due to the in vivo binding of natural antibodies to tumor cells.

Immunological Mechanisms of Tube Leukocyte Adherence Inhibition

Abstract: Enrichment and depletion of certain peripheral blood leukocyte (PBL) populations from patients indicated that the indicator and/or reactive cell manifesting nonadherence in the presence of appropriate tumor antigen was phagocytic, was glass adherent in the absence of tumor antigen, and had cell surface Fc receptors. The reactive cell, therefore, appeared to be the circulating monocyte. Two different experiments failed to show that T-lymphocytes released mediators that were responsible for inhibiting monocyte glass adherence. Immunoglobulin G purified from the sera of leukocyte adherence inhibition (LAI)-reactive patients was shown to “arm” normal PBL to react to the specific antigen. Patients with a limited tumor burden had free cytophilic immunoglobulin G antitumor antibody in their serum, whereas the serum of patients with large tumor burdens, whose leukocytes did not react in the tube LAI, did not arm. The mechanism whereby the specific tumor antigen appeared to be recognized was through the binding of cytophilic immunoglobin G antitumor antibody to Fc receptors on the cell surface of the monocyte. The serum of the nonreactive patient contained free tumor antigenic determinants capable of absorbing free cytophilic antitumor antibody or when preincubated with reactive leukocytes abrogating their LAI responsiveness. Blocking was immunologically specific; therefore, the specificity resides in the tumor antigenic determinant. The tumor antigen coat was removed by gentle trypsinization of the surface of the monocyte, and this restored the capacity of the monocyte to react in the tube LAI. About 20% of the PBL population were responsible for the manifestation of LAI when incubated with the sensitizing antigen. PBL from patients with metastatic cancer showed an identical mean nonadherence when incubated with the specific and the nonspecific cancer extracts. The mean nonadherence of PBL from patients with metastatic cancer was similar to the mean nonadherence of leukocytes from patients with limited cancer when incubated with the sensitizing antigen. Hence, we propose that the increased nonadherence to glass of leukocytes from patients with metastatic cancer results when the LAI-reactive cells (monocytes) are coated in vivo with tumor-specific antigen. Thus, the nonadherence of leukocytes from patients with limited and metastatic cancer is induced by the binding of tumor-specific antigen to the cell surface of the monocyte; in the former instance, binding occurs in vitro and in the latter in vivo .

Regulation of the immune response to tumor antigen.

Abstract: Reduction of syngeneic tumor growth in primary tumor-bearing murine hosts has been accomplished using a variety of treatments designed to decrease endogenous suppressor cell activity or augment host effector responses. Selective interference with suppressor cell function can be achieved by in vivo administration of anti-thymocyte serums at critical times during the early stages of tumor development or by continuous treatment with antiserums directed to interact with I-J determinants on suppressor cells or suppressor factors. This later mode of therapy also results in a delay in tumor appearance when suboptimal doses of tumor are given. Preferential diminution of suppressor cell precursor activity has also been observed by pretreatment of tumor recipients with low doses of cyclophosphamide. Normal animals so treated are capable of adoptively transferring primarily helper-type activity to tumor-bearing recipients. Decreased tumor growth and prolonged host survival have also been achieved using BCG as a means of augmenting host effector potential. Thus, it is possible to inhibit tumor development in a murine model by modes of immunotherapy which may be relevant to the early treatment of certain human neoplasms.

Polyoma T (tumor) antigen species in abortively and stably transformed cells.

Abstract: Stable neoplastic transformation of cells by polyoma virus requires the participation of two viral genes, designated ts-a and hr-t. The effects of mutations in these two genes on the patterns of T-antigen synthesis during productive infection have been previously described: ts- a mutants are affected in the “large” (100K) nuclear T antigen, and hr-t mutants are affected in the “middle” (36K, 56K, 63K) and “small” (22K) T agtigens. The latter are associated predominantly with the plasma membrane (56K) and cytosol fractions, rrespectively. Here we examine the expression of the various forms of polyoma T antigen in nonproductive infection (abortive transformation) as well as in stably transformed cell lines of different species. The results on abortive transformation are essentially the same as those described above for productive infection. In stably transformed cells, the middle and small T antigens are seen to various extents. The large T antigen, however, is often absent or present below the level of detection. Clones lacking the large T antigen are found most often among mouse transformants, but are also seen among rat transformants. Retention of the 100K species in transformed cells therefore appears to be, at least in part, an inverse function of the level of permissivity of the host toward productive viral infection. These findings indicate that the induction of the transformed phenotype in both abortively and stably transformed cells generally does not require the large T antigen, but rather the products of the hr-t gene.

Association of Melanoma Tumor Antigen Activity with β2-Microglobulin

Abstract: The majority of melanoma tumor antigen activity present in melanoma extracts derived from fresh tumor tissue binds to a Sepharose-anti-beta2-microglobulin adsorbent. Removal of HLA antigens from the extracts of melanoma tissue by using a KBr flotation technique did not reduce either the tumor antigen activity of the extracts or the binding of melanoma tumor antigen (MTA) activity to the Sepharose-anti-beta2-microglobulin adsorbent. The complete blocking of MTA activity by pretreating the anti-beta2-microglobulin adsorbent with beta2-microglobulin and the lack of detectable MTA binding to a Sepharose anti-normal human serum adsorbent demonstrated the specificity of the binding of MTA to the anti-beta2-microglobulin adsorbent.

Some perspectives on the transfer of cell-mediated immunity by immune-RNA.

Abstract: Ribonucleic acid extracts of lymphoid cells from immune hosts were used to transfer in vivo and in vitro cell-mediated immune reactivity to a variety of antigens. The in vivo immune responses transferred by RNA included the delayed cutaneous hypersensitivity reaction to fungal and chemically-defined antigens and the tumor-rejection reaction to guinea pig hepatoma antigens. The in vitro immune responses transferred by RNA included macrophage migration inhibition by fungal, chemically-defined, and tumor antigens. The transfer activity of RNA preparations was contained in the 8 s to 18 s species of RNA and was sensitive to RNAse but not to DNase or trypsin. Antigen was not detectable in the RNA preparations and appeared to have no role in the transfer activity. Syngeneic, allogeneic, or xenogeneic sources of RNA could transfer immune reactivity. In each system tested, the transfer of cell-mediated reactivity by RNA was specific for the antigen used to sensitize the RNA donor. The potential use of RNA-mediated transfer of immunity is discussed.

Induction of Transplantation Resistance with Soluble Simian Virus 40-induced Hamster Tumor-specific Transplantation Antigen

Abstract: Multiple injections of 3 m KCI extracts of SV40-induced hamster sarcoma cells were found to have no inhibitory effect on tumor growth in syngeneic hamsters following homologous tumor challenge. When a single injection of the same extract was administered in the range of 0.5 mg of antigen protein, a significant delay in the appearance of tumors was repeatedly observed, and a significant number of challenged animals failed to develop tumors in two of three experiments. Subsequent studies established that a single injection of the tumor cell extract generally conferred 20 to 40% permanent protection, always with a marked delay in tumor appearance. The immunity was specific in that neither immunization with normal muscle extracts nor heterologous tumor challenge resulted in protection or delay in tumor appearance. Higher or lower amounts of homologous, soluble tumor transplantation antigen given in a single injection were either without effect or promoted tumor development. The resistance observed in animals receiving a single dose of soluble tumor antigen could only be detected if the hamsters were challenged with 5 × 105 tumor cells. Challenge with only 104 tumor cells did not lead to the detection of resistance. The immunity induced by a single optimal dose of tumor antigen could be transferred to normal, uninjected hamsters at 20 days postsensitization with lymph node cells but not with peritoneal exudate cells from injected donors, suggesting that the immunity detected in animals immunized with soluble tumor extracts was cell mediated. Taken together, these data indicate that antigen dose, regimen of administration to the host, and the challenge level used to detect transplantation resistance are all important parameters to detect transplantation resistance are all important parameters to consider when using cell-free, tumor-associated transplantation antigens. These data strongly support and extend an earlier related report derived in another model with a chemically induced tumor.

Detection of Tumor Antibodies in Patients With Gastrointestinal Carcinomas by a Solid-Phase Radioimmunoassay

Abstract: Metastatic tumors from livers of 5 patients with gastrointestinal carcinomas and from the liver of 1 patient with malignant breast carcinoma were extracted with 3 M KCl; similar extracts were prepared from normal human colon and liver and from human fetal gut. The extracts were depleted of serum globulins by passage through reverse immunoadsorbent columns consisting of rabbit antibodies to the F(ab)2 fragment of human IgG and were then coupled to CNBr-activated paper disks. These "antigen" disks were used in a radioimmunoassay, with the aid of 125I-labeled rabbit antihuman F(ab')2 antibodies for the assay of circulating tumor antibodies produced by cancer patients. Statistical evaluation of the results with plasma samples from 47 patients with colorectal carcinomas and from 7 patients with other gastrointestinal disorders (polyps, villous papilloma, diverticulitis, and Crohn's disease) indicated that a significant number of patients had antibodies to cross-reactive tumor antigen(s). The cross-reactive tumor antigen(s) involved in the reaction was not detected in extracts of the gastrointestinal tract from 12-week human fetuses and did not cross-react with carcinoembryonic antigen.

Immune mechanisms in Marek's disease.

Abstract: Resistance to progressive tumor development in MD is either naturally inherited or can be induced by vaccination with apathogenic or attenuated MDV or with HVT. Studies on the effects of immunosuppression on resistance have shown that natural and vaccine induced resistance may be mediated through immune responses. Cell-mediated immune responses rather than humoral responses appear to be of principal importance. The antigen(s) against which protective cell-mediated immunity is elicited are not yet clearly delineated. Both virus-related and tumor antigens may be involved. Progress in the understanding of cell-mediated immunity in MD has been slow because of lack of reproducible in vitro tests to measure this response in infected chickens. The development of lymphoblastoid cell lines from MD lymphomas, however, has enabled the development of an in vitro cytotoxicity test. In this test, which utilizes MSB-1 cells as the target cells, a specific cell-mediated immune response, presumably against the tumor antigen, MATSA, was detected in chickens infected with MDV. Further studies using similar in vitro tests will facilitate a better understanding of the role cell-mediated immune responses might play in development of MD.

Relationship between Lymphocyte Proliferation and Tumor-Specific Cytotoxicity after Immune RNA Treatment

Abstract: Normal mouse lymphocytes were converted to effector cells cytolytic to syngeneic mouse tumor cells in vitro by incubating these lymphocytes with immune RNA (I-RNA) extracted from the lymphoid tissues of guinea pigs immunized with the same mouse tumor. This effect was tumor specific, RNase sensitive, and DNase and pronase resistant. These I-RNA-incubated lymphocytes were also able to undergo proliferation when they were co-cultured with specific tumor cells in tissue culture. Treatment with mitomycin C completely inhibited the blast transformation of I-RNA-incubated lymphocytes in response to specific tumor antigen, whereas the cytotoxic activity of mitomycin C-treated lymphocytes was not affected. There was no significant alteration in cytotoxic capability when lymphocytes were cultured for 0, 24, 48, or 72 hr after I-RNA incubation before testing. The time necessary for I-RNA-incubated lymphocytes to kill specific target cells was not different whether the lymphocytes had been cultured for 48 hr or tested immediately after I-RNA treatment. These results suggest that a proliferative step is not necessary after I-RNA treatment for lymphocytes to manifest tumor-specific cytotoxicity and that I-RNA may act upon at least two different sets of lymphocytes; one undergoing cellular proliferation in response to specific tumor antigen and the other manifesting tumor-specific cellular cytotoxicity.

Activation of an Endogenous Oncogenic Virus by Human Adenovirus in Mice

Abstract: Intracisternal A and C particles were abundant in adenovirus 12-induced primary and serially transplanted tumors in C3H/BifB mice. Malignant lymphomas were induced in 12 of 40 mice between 8–18 months when viral particulates from the tumor were inoculated into homologous newborn mice. This malignant lymphoma was morphologically different from the adenovirus 12-induced tumor from which the extract was prepared. Only a few of these viruses were observed in mice of the same strain in spontaneous hepatoma, 4-nitro-quinoline 1-oxide-induced fibrosarcoma and squamous cell carcinoma. In virus-induced malignant lymphoma adenovirus 12-specific tumor antigen was not evident by immunofluorescent method, whereas the antigen was recognized as flecks in the adenovirus 12-induced tumor cell cytoplasm. However, the localization of the fluorescent positive antigen did not coincide with the election microscopic site of the virus. The endogenous RNA type virus virogene C and/or intracisternal A may be activated by adenovirus 12 along with the carcinogenesis and appear in the tumor cell. These viruses may then induce malignant lymphoma.

A quantitative assay for tumor antigen based on inhibition of cytotoxicity of sensitized lymphocytes

Abstract: Specific inhibition of cell-mediated cytotoxicity can be used as a quantitative measure of soluble tumor antigen if highly cytolytic cells are obtained. In vitro secondary stimulation of spleen cells sensitized in vivo to the syngeneic 13762A mammary adenocarcinoma results in a lymphocyte population consistently more cytolytic than lymphocytes after primary stimulation. Maximal cytolysis requires removal of dead lymphocytes from the effector population. Soluble tumor antigen (STA) is detected only in supernatants of 13762A mammary tumor cultures grown in the presence of the proteolytic enzyme inhibitor, epsilon-amino caproic acid. Soluble MTM antigen preparations block lymphocytes immune to the mammary tumor but not lymphocytes immune to a second mammary adenocarcinoma (R3230) or to allogeneic spleen cells. Soluble antigen preparations from other tumors do not inhibit lymphocytes specifically cytolytic to the 13762A tumor. Additional evidence that the STA preparation contains tumor antigen is its ability to induce specific cytolytic lymphocytes and partial protection from challenge with live MTA tumor cells.

Cellular Cytotoxicity and Serum Inhibition in Normal Mice following Transfer of Xenogeneic Tumor-sensitized Cells

Abstract: Findings from previously reported investigations revealed that lymphoid and myeloid cells from tumor-bearing mice, when transferred to normal syngeneic mice never exposed to a tumor, imparted “information” which resulted in the production of tumor-specific cytotoxic cells by recipients. The present studies determined the cytotoxicity of cells from normal mice which were recipients of cells obtained from rats (xenogeneic) sensitized to mouse tumor. Normal rat lymph node cells (LNC) or spleen cells (SPC), when evaluated prior to their transfer, were found to be noncytotoxic to tumor target cells. LNC or SPC from rats sensitized to mouse tissue, either normal or tumor, were highly cytotoxic. Subsequent to the transfer of LNC or SPC from normal rats or from those sensitized to H-2 antigen (normal mouse tissue), little or no cytotoxicity was identified in LNC, SPC, or macrophages cultured from bone marrow cells of normal recipient mice. When the transferred cells were derived from rats sensitized to both H-2 and tumor antigen, i.e. , tumor cells, and the target cells were from the same tumor used for sensitization, maximal cytotoxicity was demonstrated in cultured macrophages, LNC, and SPC of normal mouse recipients. An increase in cellularity of recipient nodes, spleen, and bone marrow occurred following transfer of tumor-sensitized xenogeneic cells, unsensitized rat cells, or those cells sensitized to normal mouse spleen, indicating an equivalent recruitment of host cells by all types of xenogeneic cells transferred. The behavior of the recruited cells, i.e. , tumor cytotoxicity, was entirely dependent upon the use of tumor for sensitization of donor cells. Findings similar to those in the syngeneic system indicate that sera from normal cell recipients inhibit the cytotoxicity of cells derived from tumor-bearing animals. The findings indicate that information has been transferred by tumor-sensitized xenogeneic cells to normal animals that have never been exposed to tumor cells, which results in their production of tumor-specific cytotoxic cells. H-2-sensitized xenogeneic cells failed to produce such an effect. The relation of these findings to the use of xenogeneic cells for passive tumor immunotherapy is commented upon.

Comparison of simian virus 40-induced mouse and hamster tumor-specific transplantation antigens.

Abstract: The tumor-specific transplantation antigen (TSTA), which appears on papovavirus-induced sarcomas of the hamster, has been demonstrated to be common in any cell type transformed by a given virus. Other studies have suggested that cell-free TSTA has been successfully isolated from mouse sarcoma cells induced in vitro by simian virus 40 (SV40). Considerable work has been done toward purifying and identifying this mouse TSTA. We obtained preparations from the laboratory reporting the isolation of TSTA from the SV40-induced mouse sarcoma cells as well as cell lines from which the preparations of TSTA had been derived. These extracts, as well as fresh extracts made from the appropriate SV40-induced mouse tumor line, were tested for their ability to interrupt tumor production in mice after challenge with homologous and heterologous sarcomas and to prevent SV40 primary tumor induction in hamsters. The findings indicated that TASTA extracted from SV40-induced mouse sarcoma cells as well as from the intact irradiated mouse sarcoma cells failed to prevent SV40 oncogenesis as well as tumor transplantation in the hamster, but it was capable of preventing specific tumor transplantation when used as a vaccine in mice. Human and hamster cells transformed by SV40 were capable of interrupting SV40 oncogenesis inmore » the hamster. These results suggested that the so-called TSTA, which is immunogenic and induces specific transplantation resistance in mice to SV40-induced mouse sarcomas, was not the same TSTA that appears on human, rat, and hamster cells and that is produced by SV40 in those cell types. Further, tumor antigen may be the immunizing component which others have isolated as a transplantation-like antigen from mouse sarcoma cells. An alternative explanation would be a peculiar histocompatibility (H-2) barrier in the hamster to the immunogenicity of TSTA induced in mouse cells.« less

Structure of tumor antigen on hybrid cells between mouse mammary ascites tumor and mouse fibroblast L cells

Abstract: Somatic cell hybrids between mouse fibroblast L cells and MM2 mouse mammary ascites tumor grown in BALB/c mice were isolated and the structures of tumor-associated surface antigen of the hybrid cells, and parental MM2 and mouse L cells were investigated by the methods of radioiodination of membrane proteins, immunoprecipitation with a specific antiserum against tumor-associated surface antigens of MM2 tumor (anti-MM2 serum), and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Two molecules of 105,000 and 76,000 daltons were detected on the MM2 cell surface, but no MM2 tumor antigen was detected on the mouse L cells. On the hybrids between these two kinds of cells, in addition to the two MM2 tumor antigens, molecules of 48,000-51,000 and 12,000 daltons were observed. On Sendai-virus-infected mouse L cells only a molecule of 68,000 daltons was detected by the anti-MM2 serum, and furthermore this molecule was also detected by normal mouse serum, indicating that antibodies against Sendai virus were contaminating in both the anti-MM2 and normal mouse sera used, and thus the molecules detected on the hybrid cells were distinguishable from possible viral components of Sendai virus on the hybrid cells. The results indicate that somatic cell hybrids between mouse L cells and MM2 tumor grown in BALB/c mice expressed on their cell surface the molecules that were not exposed on either parent cell. The experiments comparing newly detected molecules with the H-2 antigen suggested that they were similar to H-2 in their electrophoretic pattern.