Tumor-specific Transplantation Antigen Research Articles

Effects of Radiotherapy on Ehrlich’s Ascetic Carcinoma in Swiss Albino Mice: An Experimental Study

Background: Experimental tumors have great importance in modeling, and Ehrlich ascites carcinoma (EAC) is one of the most common tumors. EAC is referred to as an undifferentiated carcinoma and is originally hyperdiploid, has high transplantable capability, no-regression, rapid proliferation, shorter life span, 100% malignancy, and also does not have tumor-specific transplantation antigen. The current concepts that radiotherapy alone or with cancer chemotherapy is administered at a dose to the maximum a patient can tolerate before the onset of severe and even life-threatening toxicity is still in wide clinical use. This study was conducted to evaluate the response of radiotherapy in the treatment of EAC. Materials and Methods: A mouse bearing the tumor strain was taken from our laboratory in the Department of Pathology, IPGMER, Kolkata, where the strain was being maintained serially by inoculation of malignant cells into healthy mice every 8–10 days. In our work, altogether 25 mice were taken for each set of experimental work. They were divided in four groups of 5–10 mice in each group. The various parameters to assess the response of various therapeutic schedules were regression of tumor by decrease in body weight of mice and decrease in abdominal girth; cell count of ascetic fluid and morphological changes of tumor cells after treatment with drugs and to study the percentage viability of the cells. Results: All the mice in Group I gained weight steadily. Mice of Group II were unaffected by single dose whole body radiation and they behaved as mice of Group I. All mice of Group III died within 20–25 days. Conclusion: Cell changes were observed but not as marked. Cell viability was as high as 65% after treatment as compared to tumor control which showed a viability of about 75%.

P53 and The Immune Response: 40 Years of Exploration-A Plan for the Future.

The p53 field was born from a marriage of the techniques of cancer virus research and immunology. Over the past 40 years, it has followed the path of cancer research. Now cancer treatments are turning to immunotherapy, and there are many hints of the role of the p53 protein in both the regulation of the innate immune system and as an antigen in adaptive immune responses. The p53 gene and protein are part of the innate immune system, and play an important role in infectious diseases, senescence, aging, and the surveillance of repetitive DNA and RNAs. The mutant form of the p53 protein in cancers elicits both a B-cell antibody response (a tumor antigen) and a CD-8 killer T-cell response (a tumor-specific transplantation antigen). The future will take the p53-immune response field of research into cancer immunotherapy, autoimmunity, inflammatory responses, neuro-degeneration, aging, and life span, and the regulation of epigenetic stability and tissue regeneration. The next 40 years will bring the p53 gene and its proteins out of a cancer focus and into an organismic and environmental focus.

History of the development of tumor markers of the digestive tract cancers

Tumor markers are gene products which signal the occurrence of tumors in different organs as well as their response to surgery and chemotherapy. The discovery of tumor markers occurred after the demonstration of tumor-specific transplantation antigens in chemically or virally induced tumors in syngenic rodents. The history of currently used tumor markers began in the 1940s, the first discovered being alpha-fetoprotein in 1956, followed by that of carcinoembryonic antigen in 1965. Since then the range of tumor markers has widened continously. Their chemical structure and genetics is now well known. Some may play part in tumor growth and development of metastases. The potential uses of tumor markers are general or high risk population screening, adjunct in diagnosis of cancer, preoperative indicator of tumor burden, indicator of therapeutic success, evidence of postoperative recurrences and use in tumor localization. However, there is no ideal tumor marker fulfilling all the criteria. Isotope-labeled anti-carcinoembryonic antigen antibodies and small molecular E-selectin inhibitors could play a role in the molecular radio- and chemotherapy of colon and pancreatic carcinomas.

Ehrlich ascites carcinoma

Experimental tumors have great importance in modeling, and Ehrlich ascites carcinoma (EAC) is one of the commonest tumors. EAC is referred to as an undifferentiated carcinoma and is originally hyperdiploid, has high transplantable capability, no-regression, rapid proliferation, shorter life span, 100% malignancy and also does not have tumor-specific transplantation antigen (TSTA). Frequently, tumor virulence increases via repetitious passages, while the proliferating rate of such tumors increases gradually. However, the differentiation gradually disappears, while the cells get free growth control mechanisms, gain hetero-transplantability and in the end, they are converted to the ascites’ form. EAC resembles human tumors which are the most sensitive to chemotherapy due to the fact that they are undifferentiated and that they have a rapid growth rate. The ideal drug being ineffective or minimally effective for normal cells have been focused on, and at this point, the usage of natural sources as an alternative cancer therapy is thought to have a great value for cancer control and programs’ destruction. Key words : carcinoma, transplantability

Proteomic identification of differentially expressed genes in mouse neural stem cells and neurons differentiated from embryonic stem cells in vitro

Embryonic stem (ES) cells are pluripotent stem cells and give rise to a variety of differentiated cell types including neurons. To study a molecular basis for differentiation from ES cells to neural cells, we searched for proteins involved in mouse neurogenesis from ES cells to neural stem (NS) cells and neurons by two-dimensional gel electrophoresis (2-DE) and peptide mass fingerprinting, using highly homogeneous cells differentiated from ES cells in vitro. We newly identified seven proteins with increased expression and one protein with decreased expression from ES cells to NS cells, and eight proteins with decreased expression from NS cells to neurons. Western blot analysis confirmed that a tumor-specific transplantation antigen, HS90B, decreased, and an extracellular matrix and membrane glycoprotein (such as laminin)-binding protein, galectin 1 (LEG1), increased in NS cells, and LEG1 and a cell adhesion receptor, laminin receptor (RSSA), decreased in neurons. The results of RT-PCR showed that mRNA of LEG1 was also up-regulated in NS cells and down-regulated in neurons, implying an important role of LEG1 in regulating the differentiation. The differentially expressed proteins identified here provide insight into the molecular basis of neurogenesis from ES cells to NS cells and neurons.

Autoantibodies in sera of pancreatic cancer patients identify recombination factor Rad51 as a tumour-associated antigen.

The recombination factor Rad51 is highly expressed in human pancreatic adenocarcinoma. In this study we asked whether high-level expression of Rad51 antigen stimulates a B-cell response leading to Rad51-specific autoantibodies in human pancreatic cancer patients. Sera of patients suffering from pancreatic cancer (57) as well as sera of healthy donors (86) were screened for Rad51 autoantibodies by Western-blot analysis. Rad51 over-expressing cell lines were used as antigen source. Four out of 57 (7%) sera tested were found positive for Rad51 autoantibodies of IgG subclass, while all 86 control sera were negative. This observation identifies Rad51 as a tumour-associated antigen in pancreatic adenocarcinoma. Since high-level expression of Rad51 is restricted to tumour cells, Rad51 is also a tumour-specific antigen. Further analyses should reveal whether Rad51 might also function as a tumour-specific transplantation antigen (TSTA) and whether it might serve as a target for new immunotherapeutical approaches.

In vivo acquired mechanisms of tumor cells local defense against the host innate immunity effectors: implication in specific antitumor immunity

As shown earlier, the cells transformed in vitro by several different oncogenes, or spontaneously, during in vivo growth in normal hosts would be gradually replaced by the highly-tumorigenic descendants co-expressing high H 2O 2-catabolizing and PGE 2-releasing activities. Acquisition of (H 2O 2 CA+PGE S) phenotype provides the cells with local defense mechanisms against the host innate immunity effectors. However, it remained unknown, whether the expression of (H 2O 2 CA+PGE S) phenotype is implicated in susceptibility of tumor cells expressing tumor-specific transplantation antigens to rejection in immune animals. Here, with the use of SV40 in vitro transformed parental cells, negative in expression (H 2O 2 CA+PGE S) phenotype, and their in vivo selected descendant tumor cell lines expressing this phenotype, we show that: (1) the rates of in vivo selection of the parental SV40 tumor cells expressing (H 2O 2 CA+PGE S) phenotype are the same in normal and SV40-immune animals; (2) in vivo selected SV40 tumor cells expressing (H 2O 2 CA+PGE S) phenotype, although they retain specific immunosensitivity, are 100 times less effectively rejected in SV40-immunized animals, as compared with their in vitro SV40-transformed parental cells. Thus, in vivo acquired immunologically non-specific local mechanisms of tumor cells defense against the host innate immunity effectors, significantly decreases the effectiveness of their specific immunorejection.

Tumors express both unique TSTA and crossprotective 44 kDa oncofetal antigen

Tumors of inbred rodents and humans generally express a shared tumor-associated transplantation antigen (TATA)-like oncofetal antigen (OFA) and tumor-specific transplantation antigen (TSTA), which stimulate cytotoxic T lymphocyte (CTL) tumor rejection responses. Immunoregulatory CD8 + OFA-specific suppressor T cells are also stimulated, which promote tumor development via interleukin 10 secretion, inhibiting CTL function. Here, Joseph Coggin and colleagues argue that future investigations must distinguish responses to OFA and TSTA.

A short peptide eluted from the H-2Kb molecule of a polyomavirus-positive tumor corresponds to polyomavirus large T antigen peptide at amino acids 578 to 585 and induces polyomavirus-specific immunity.

A short peptide in complex with the H-2Kb molecule on PyRMA, a polyomavirus transfectant of the mouse lymphoma cell line RMA, was identified as a polyomavirus tumor-specific transplantation antigen. The peptide was obtained by affinity chromatography, acidic extraction, and reverse-phase high-pressure liquid chromatography (HPLC). In one HPLC fraction, a peptide sequence in which 5 of 8 amino acids, GKxGLxxA, corresponded to residues 578 to 585 of polyomavirus large T antigen was identified. In tumor rejection assays, we therefore tested three related synthetic peptides, corresponding to the octapeptide LT 578-585, GKTGLAAA; the nonapeptide LT 578-586, GKTGLAAAL; and the decapeptide LT 578-587, GKTGLAAALI. The octapeptide was found to give the most effective immunization against the outgrowth of the polyomavirus DNA-positive PyRMA tumor. However, none of the three peptides immunized against the original polyoma-virus-negative RMA line.

Identification of functional domains of adenovirus tumor-specific transplantation antigen in types 5 and 12 by viable viruses carrying chimeric E1A genes.

The adenovirus (Ad) E1A gene induces in immunized animals a strong tumor transplantation (TSTA) immunity against Ad tumors. Such immunity with group-A and group-C viruses is highly group-specific and no cross-protection is detected between serotypes 5 and 12. This fact was used to map the domains of the Ad5 and Ad12 E1A gene products, respectively, which control the TSTA. We constructed a library of 8 recombinant viruses (H5sub1101 through H5sub1108) which carry chimeric Ad5/Ad12 E1A genes in the background of Ad5. The chimeric genes are functional and these viruses are viable. Some of these constructs induce strong and highly specific tumor syngraft immunity in immunized rats. The viruses carrying the 5' terminus of the first E1A exon derived from Ad12 (viruses H5sub1101, H5sub1102 and H5sub1103) induce strong protection against Ad12 tumors irrespective of the rest of their E1A sequence. The viruses which carry the second exon of the Ad5 E1A gene (viruses H5sub1101, H5sub1102 and H5sub1106) protect against group-C tumors, regardless of the origin of the rest of their E1A gene. The 2 viruses that carry the 5' E1A terminus of the first exon of Ad12 and the second exon of Ad5 (H5sub1101 and H5sub1102) are thus effective in inducing immunity against Ad12 tumors as well as against Ad2 tumors. The viruses which carry the 5' terminus of the first exon derived from Ad5 and the second exon of Ad12 (H5sub1107 and H5sub 1108) fail to induce immunity against either tumor. Expression of only the truncated 5' terminus of the Ad12 E1A gene (viruses H5sub1104 and H5sub1105) is sufficient for induction of Ad12 TSTA. Our results provide direct and unequivocal in vivo evidence that TSTA activities of adenovirus groups A and C are controlled by different domains of their respective E1A genes. The Ad12 TSTA is a function of the 5' terminus of the first E1A exon, while the Ad5 TSTA is coded for by the 3' exon of its E1A gene.

Immunotherapy with a tumor-infiltrating lymphocyte clone, soluble antigen, and cyclophosphamide.

A tumor-specific cytotoxic T-lymphocyte clone derived from bulk cultures of tumor-infiltrating lymphocytes attenuated the outgrowth of methylcholanthrene (MCA)-induced fibrosarcomas in C3H/HeJ mice. In 4-hour chromium 51-release assays, bulk cultures of tumor-infiltrating lymphocytes showed nonspecificity for MCA-induced tumors (MCA-F, MCA-D, MCA-SP), YAC-1, and EL-4. In contrast, a cytotoxic T-lymphocyte-cloned line specifically killed MCA-F, but not MCA-D or MCA-SP. Cytotoxic T-lymphocyte line 8 protected syngeneic hosts in local and systemic adoptive transfer assays. Hosts bearing 4-day-established MCA-F tumor cells received single agents or combinations of isoelectrophoretically purified butyl alcohol-extracted tumor-specific transplantation antigen (1 microgram/wk), cyclophosphamide (20 mg/kg on days 4 and 11), and/or cytotoxic T-lymphocytes (1 x 10(7) cells on days 7 and 14). While the mean tumor diameter was 11.6 +/- 1.3 mm in untreated hosts or after single treatments, the combination of tumor-specific transplantation antigen and cyclophosphamide along with the cytotoxic T-lymphocyte clone resulted in tumor diameters of 1.8 +/- 0.5 mm. The triple combination prolonged host survival from 39.6 +/- 1.6 to 57.2 +/- 4.7 days compared with antigen and cyclophosphamide treatment.

Tumor-specific antigens of mouse tumors.

This article reviews the serological analysis of cell surface antigens of chemically induced sarcomas of murine origin. This analysis, which was aimed at molecular characterization of the highly restricted tumor specific transplantation antigens of sarcomas, led to the initial biochemical identification and characterization of p53. The results of this early study clearly pointed to p53 as playing a key role in cellular proliferation and transformation. Current research of the tumor-specific or -associated antigens of chemically-induced sarcomas and melanomas of murine origin is also discussed.

Can oncogene (RAS) activation predict susceptibility of human melanoma to activated lymphocytes and, therefore, the clinical response of such neoplasms to adoptive immunotherapy?

The expression of activated ras oncogenes was found to be associated with that of tumour-specific transplantation antigens in mouse tumours, which can be cured by adoptive immunotherapy with T lymphocytes and interleukin-2 (IL-2). A similar association is here proposed to exist between RAS oncogene activation (mutation) in human melanoma and susceptibility of these tumours to the lytic action of activated lymphocytes (both lymphokine-activated killers and cytotoxic T cells) which have been used, along with IL-2, in the adoptive immunotherapy of advanced melanomas. The limited clinical response (15-25%) of melanoma patients to different immunological therapies is, therefore, considered to be due to a similar frequency of immunogenic, RAS+ melanomas. The authors thus suggest that RAS activation might be a marker of immunogenicity and that only the subset of melanoma cells expressing activated RAS will in turn possess tumour antigens which can be the target of immunotherapeutic, activated lymphocytes. It is then predicted that RAS+ melanomas will be more susceptible to adoptive immunotherapy than RAS-counterparts.

Activation of ras oncogenes and expression of tumor‐specific transplantation antigens in methylcholanthrene‐induced murine fibrosarcomas

The DNA of 22 fibrosarcomas, newly induced in BALB/c mice by subcutaneous doses of 3-methylcholanthrene (3-MCA), was tested in NIH 3T3 transformation assay. Activation of K-ras and N-ras was found in 7 and 3 cases respectively. No H-ras activation was detected. Polymerase chain reaction and oligonucleotide hybridization performed on the DNA of the 22 sarcomas revealed 5 cases of K-ras mutation at codon 12, 3 at codon 13 and 1 at both codons. One case of K13 mutation was not detectable by transfection. Three cases of mutation at codon 61 of N-ras were also found, one of which was simultaneous with a K12 mutation. Tumor-specific transplantation antigens (TSTA) were assessed in the 22 original tumors. Altogether 16 sarcomas were immunogenic, with the highest frequency of TSTA+ tumors (10/11 and 5/6) in the groups given 1.0 and 0.1 mg of 3-MCA respectively, the lowest (1/5) in that with 0.01 mg of carcinogen; ras mutations occurred in the DNAs of 11 out of the 16 TSTA+ sarcomas, but none of the DNAs of the 6 TSTA- tumors showed ras mutation. The results suggest that 3-MCA-induced transformation of subcutaneous fibroblasts can involve mutations in codons 12, 13 or 61 of K- and N- but not H-ras gene and that such mutation is accompanied by the expression of TSTA.

Vaccination against polyoma virus (PYV) tumors using vaccinia‐PYV recombinants: A major tumor‐specific transplantation antigen (TSTA) epitope resides within the C‐terminal segment of middle‐T protein

We previously reported that inoculation of rats with live vaccinia virus (VV) recombinants VVpyMT, VVpyLT expressing either the middle-T (MT) or large-T (LT) proteins of polyomavirus (PyV) can elicit immunity to challenge with syngeneic PyV-tumor cells. We now report the results of cross-vaccination studies. VVpyMT was ineffective against cells expressing LT protein but prevented development of MT-expressing cells. Conversely, the VVpyLT was ineffective against MT-expressing cells. In the two experiments performed, tumor growth enhancement rather than retardation was observed in VVpyLT-vaccinated animals receiving PyV-LT (FRLTI) challenge tumor cells. To determine the location of the major TSTA within MT, a further VV recombinant (VVpyMT/Cfr) was constructed that expresses only the unique C-terminal segment of MT. VVpyMT-Cfr and VVpyMT were equally effective in eliciting tumor immunity, indicating the presence of a major TSTA epitope within the unique C-terminal region of MT.

P53-plus-ras-transformed rat embryo fibroblasts express tumor-specific transplantation antigen activity which is shared by independently transformed cells

p53-plus-ras-transformed rat cell lines express a tumor-specific transplantation antigen that is common to a number (85%) of independently derived p53-plus-ras-transformed cell lines. This has been shown by immunizing rats with irradiated p53-plus-ras-transformed cells and demonstrating protection of these animals by subsequent live-cell tumor challenge. Several c-myc-plus-ras-transformed cell lines (54% of the lines tested) and one adenovirus E1a-plus-ras-transformed cell line (9% of those tested) were shown to share a common tumor-specific transplantation antigen by their ability to immunize a rat against a p53-plus-ras cell line challenge. Several experimental approaches have been used to fractionate and identify the antigen common to these cell lines. The experimental results reported here make it clear that the p53 protein common to most of these transformed cell lines is not likely to be the tumor-specific transplantation antigen.

Active Specific Chemoimmunotherapy of Lymph‐node Metastasis from a Poorly Immunogenic Murine Fibrosarcoma

The fibrosarcoma MCA‐SP, which was recently induced with methylcholanthrene (MCA) in C3H/ HeJ mice, displays poor immunogenicity in in vivo prophylaxis. A cell variant MCA‐SPN1, which bears a tumor‐specific transplantation antigen (TSTA) cross‐reactive with the parental line MCA‐SP, was selected because of its proclivity for axillary lymph‐node metastases. Although these lymph‐node metastases were resistant to sinecomitant (post‐excisional) immunity, they were susceptible to combined active and passive specific Chemoimmunotherapy, using tumor‐specific, 1‐butanol‐extracted, preparative isoelectric focusing‐purified, TSTA (1 fig weekly sc injections), cyclophosphamide (CY, a single intraperitoneal 20 mg/kg dose), and adoptive transfer of immune splenic T lymphocytes, which had been re‐stimulated in vitro with extracted TSTA and interleukin‐2. This triple regimen both reduced the incidence of spontaneous lymph‐node metastases, and prolonged the survival of tumor‐bearing, as well as tumor‐resected hosts. The results from local adoptive transfer assay using T‐lymphocyte snbpopulations of spleen and lymph nodes in these treated hosts suggested that Lyt 2+ cytotoxic T‐lymphocytes (CTL) mediated in vivo tumor‐neutralization. Thus TSTA/CY/CTL therapy activates tumoricidal host responses effective against the poorly immunogenic MCA‐SP tumor and its lymph‐node metastases.

A single peptide derived from the sequence common to polyoma small and middle t-antigen induces immunity against polyoma tumors

Polyoma virus, an oncogenic virus, fails to induce tumors in immunocompetent rodents due to T cell-dependent mechanisms. The target recognized by the immune system has been functionally defined as polyoma tumor-specific transplantation antigen (TSTA) and has been postulated to be related to the virus three early proteins small T (ST), middle T (MT), and large T (LT) antigens. We show here that immunization with a synthetic peptide corresponding to amino acids 162–176 of polyoma MT and ST was able to decrease tumor progression of polyoma tumors, but not of nonpolyoma tumors. This indicated that these amino acids constitute an epitope of the polyoma tumor-specific transplantation antigen.

Novel class I-like molecule expressed on a murine leukemia virus-transformed cell line

A retrovirus-induced tumor cell line, which expresses no H-2K or H-2D class I molecules, appears to express a tumor-specific transplantation antigen which induces tumor rejection in vivo and cytotoxic T lymphocyte generation in vitro without prior immunization and thus resembles class I molecules. In addition, although these tumor cells express no detectable class I molecules, they do express β 2 microglobulin and a 55- to 60-kDa β 2 microglobulin-associated protein. Northern analysis demonstrated that these cells express no RNA hybridizing to class I probes, suggesting that neither the tumor-specific transplantation antigen nor the β 2 microglobulin-associated protein, if these are different, are encoded by known class I genes.

Heat-shock proteins, Hsp84 and Hsp86, of mice and men: two related genes encode formerly identified tumour-specific transplantation antigens

Mouse cDNA clones have been isolated with the help of Drosophila melanogaster 82-kDa heat-shock protein (Hsp82)-coding sequences as hybridization probe. Sequencing of the overlapping mouse clones reveals a long open reading frame (ORF) that encodes a polypeptide of 83.3 kDa which shows about 80% similarity to the respective Drosophila Hsp82 amino acid sequence. The N-terminal half of this cDNA cross-hybridizes to a different class of mouse cDNA clones indicating a related gene. Northern blot hybridization experiments reveal a 2.6-kb poly(A) + RNA when probed with the hsp84 clone and a 2.85-kb signal with the hsp84-related cDNA. The amino acid sequences deduced from the contiguous ORF of the hsp84 and the hsp84-related cDNA coincide with the N-terminal sequence of formerly identified 84-kDa and 86-kDa tumour-specific transplantation antigens (Ullrich et al., 1986). In addition, the amino acid composition of the putative 84-kDa mouse Hsp described here is very similar to that of the 84-kDa tumour antigen described by Ullrich et al. (1986). Both observations corroborate the assumption that these Hsps are identical to the described 84-kDa and 86-kDa tumour-specific transplantation antigens. Using these mouse hsp gene clones as hybridization probes we also isolated the corresponding pair of human cDNA clones. Comparison of the respective sequences reveals a strong evolutionary constraint on these two genes in mouse and man.