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[Cancer Research 63, 6051-6055, September 15, 2003]
© 2003 American Association for Cancer Research

Immunology

On the Role of Unmutated Antigens in Tumor Rejection in Mice with Unperturbed T-cell Repertoires1

Supria Sarma2,,3, Xue-Feng Bai2, Jin-qing Liu, Kenneth F. May, Jr., Pan Zheng and Yang Liu4

Division of Cancer Immunology, Department of Pathology, Ohio State University Medical Center, Columbus, Ohio 43210


   ABSTRACT
Top
 ABSTRACT
INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
We investigate here whether P1A, which was the first CTL-recognized and unmutated tumor antigen to be identified, is a tumor rejection antigen for J558 plasmacytoma in mice with an unperturbed T-cell repertoire. We show that although transgenic mice expressing P1A in the thymus have almost complete deletion of P1A-reactive T cells, they reject the B7-1-transfected J558 at a rate comparable with wild-type mice. Thus, P1A is not a necessary tumor rejection antigen for the J558 tumor cells. On the other hand, if anti-P1A CTL response is sufficient for tumor rejection, tumor cells must lose the antigenic epitope to evade CTL destruction. To test this, we analyze whether tumor cells escaping J558-B7 immune spleen cells harbor mutations in the P1A epitope. We find that although the spleen contained a high proportion of P1A-reactive T cells, the recurrent tumor cells have no mutation in the P1A antigenic epitope and remain susceptible to lysis by P1CTL. Thus, the antigen-bearing tumor cells can evade immune destruction in the presence of a high number of P1A-reactive T cells. Taken together, our results demonstrate that in mice with a normal TCR repertoire, substantial numbers of P1A-reactive T cells are neither necessary nor sufficient for tumor rejection and raise interesting questions regarding the significance of T-cell response against unmutated tumor antigens.


   INTRODUCTION
Top
 ABSTRACT
 INTRODUCTION
MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
Although the existence of cancer immunity has been clearly demonstrated by classical rejection experiments (1) , identification of tumor antigens recognized by T cells (2, 3, 4, 5, 6, 7, 8, 9) has substantially strengthened the notion of cancer immunity. However, of the numerous cancer antigens identified thus far, only a minority have been causatively linked to tumor rejection (10, 11, 12) and would thus be considered bona fide tumor rejection antigens.

Because of the technical difficulties in identifying tumor antigens, most tumor antigens were initially identified using T-cell clones from cancer patients or animals that have received different forms of cancer cells (8 , 9) . This can be followed by at least three different tests to determine whether they are tumor rejection antigens. First, the tumor antigen can be used to immunize mice, and the immunity will be evaluated by subsequent tumor challenge (13 , 14) . The same strategy has been used for cancer patients, whose response is evaluated based on the rejection of preexisting cancer (15) . Second, the antigen-specific T-cell lines can be used for adoptive immunotherapy in both cancer patients and mice that either bear tumors at the time of treatment or one challenged with tumor cells (10 , 16 , 17) . The third test is whether loss of given tumor antigens allows evasion of host immunity by cancer cells (18) .

These approaches all have caveats, e.g., although immunization experiments can reveal the value of a given tumor antigen in the induction of rejection immunity, they do not necessarily prove that the immunogen is the target antigen responsible for rejection, as antigenic repertoire can be expanded during the immune response, a phenomenon called epitope spreading (19) . The second approach can confirm whether the T cells generated under nonphysiological conditions, such as T-cell clones, or transgenic T cells are capable of rejecting tumors (20) . This method, however, does not necessarily reveal whether the antigens identified can be used as immunogens for cancer vaccines. The third approach, although capable of identifying whether reactivity against given tumor antigen is essential for tumor rejection, has not been widely used for in vivo analysis. This is in part because for most tumor models, antigenic variation selected by host immunity has not been systematically analyzed.

P1A was the first natural, CTL-recognized tumor antigen to be identified (2) . Several lines of evidence support its role as a tumor rejection antigen. First, CTL clone specific for P1A epitope 35–43 can cause tumor rejection (17) . Similarly, we showed that P1A-reactive transgenic T cells can reject tumors derived from B7-1, B7DC/PDL-2, and B7H-transfected tumor cells even if the tumors have reached >1.5 cm in diameter before T-cell adoptive transfer (20, 21, 22) . Although the complete rejection of unmodified J558 cells has not been realized, significant shrinkage of tumors has been observed within the first 2 weeks of T-cell adoptive transfer (20 , 21) . Second, immunization with P1A-transfected, unrelated tumor cells can induce rejection of the P1A-expressing mastocytoma P815, and this depends on immunity to P1A as tolerance to P1A abrogated the immunogenicity of the P1A-transfected cells (11) . Nevertheless, it should be pointed out that immunization with P1A peptide or P1A-expressing vaccinia virus can prime P1A-reactive T cells but does not lead to tumor rejection (13) . Consistent with these observations, we have observed that with induction of significant priming of P1A-reactive T cells by B7-1-transfected tumor cells, there is no cross-protection among P1A-expressing tumor cells (23) . These results raise the possibility that in a host with an unperturbed T-cell repertoire, P1A-reactive T cells may not be sufficient to cause tumor rejection.

In this study, we take two approaches to address whether P1A-reactive T cells are necessary and sufficient for rejection of a P1A-expressing plasmacytoma J558 in mice with a repertoire of polyclonal T cells. We report that tolerance to P1A does not abrogate B7-1-mediated induction of tumor immunity. Moreover, tumor cells with intact P1A antigen can evade a strong host immune response that includes a high frequency of P1A-reactive T cells. Our results demonstrate that in mice with a polyclonal T-cell repertoire, P1A is not a strong tumor rejection antigen, although under some circumstances, P1A-reactive T cells can cause tumor rejection. This also raises interesting questions regarding the biological significance of the T-cell response against the unmutated tumor antigens.


   MATERIALS AND METHODS
Top
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
RESULTS
 DISCUSSION
 REFERENCES
 
Experimental Animals and Tumor Cell Lines.
BALB/c mice were purchased from Charles River Laboratories under contract from the National Cancer Institute. Transgenic mice expressing the P1A gene under the control of mB-1 promoter and Eµ-enhancer have been described previously (24) . BALB/c RAG-2(-/-) mice were purchased from Taconic Laboratories (Albany, NY). Plasmacytoma cells transfected with either vector alone or B7-1 have been described previously (25) .

Cytotoxic T-cell Assays.
51Cr release assays were used to measure cytotoxicity of both freshly isolated TILs and the transgenic T cells specific for P1A after in vitro activation, as has been described (26) .

Tumorigenicity Assay.
Tumor cells (5 x 106 J558) were injected s.c. into either wild-type, P1A-transgenic, or RAG-2(-/-) mice. The tumor incidence and growth kinetics were determined by physical examination.

Adoptive Therapy with Spleen Cells.
Spleen cells were harvested from the BALB/c mice that rejected the B7-1-transfected tumors, and immune spleen cells were injected into the recipient mice i.v. at a dose of 50 x 106/mouse. The recipients were RAG-2(-/-) BALB/c mice that bore J558 tumors of ~1.5–2 cm in diameter.

Flow Cytometry.
Cell surface expression of H-2Ld was detected using biotinylated mAb5 28-14-8 (BD PharMingen, San Diego, CA) followed by phycoerythrin-labeled streptavidin. To determine the binding of H-2Ld:peptide complex to transgenic T cells, we used the H-2LdIg dimer purchased from BD PharMingen according to manufacturer’s instruction. Briefly, 3 µg of peptides were incubated with 4 µg of H-2LdIg and ß2 microglobulin complex at 4°C for 48 h in a total volume of 200 µl. Phycoerythrin-conjugated monoclonal rat antimouse IgG1 antibodies were added to the solution 1 h before it was used to stain spleen cells from transgenic mice whose T cells had expressed the TCR specific for the H-2Ld:P1A peptide complex. After washing away the unbound complex, the spleen cells were fixed with 1% paraformaldehyde in PBS and analyzed by flow cytometry.

Molecular Characterization of P1A Gene.
The P1A gene fragments were amplified by PCR using 5'-GCTAGCTTGCGACTCTACTCTTATCT-3' as the forward primer and 5'-TCCACATCCCTTTCATACTGCTCC-3' as the reverse primer. The PCR products were cloned and sequenced.


   RESULTS
Top
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
DISCUSSION
 REFERENCES
 
1. Tolerance to P1A Did Not Prevent Rejection of B7-1-transfected J558 Cells.
We have reported that overexpression of P1A in the thymus of P1A transgenic mice caused strong clonal deletion of T cells with a transgenic TCR specific for P1A35–43 (24 , 27) . It is therefore of interest to use the mice to determine whether tolerance to P1A prevented rejection of J558-B7. We first determined whether other P1A reactive T cells in mice with a polyclonal T-cell repertoire are also tolerized, by injecting groups of P1A transgenic mice and wild-type littermates with 5 x 106 J558-B7 and then isolated TIL from the tumors 14–17 days after injection. TIL were used as effectors against 51Cr-labeled targets. Consistent with our previous observations (25 , 26) , TILs isolated from wild-type mice have strong cytotoxicity against J558-B7 tumor cells and that the cytotoxicity is mediated by CTL. It is also evident that the TIL from the normal mice recognize P1A peptide-pulsed P388D1 cells but with only half the efficiency with which they recognize J558-B7. This suggests that the normal mice are also mounting responses against tumor antigens other than the P1A35–43 epitope. In contrast, TIL from the P1A transgenic mice recognized the J558-B7 tumors but failed to show any specificity for P338D1 targets pulsed with the P1A35–43 peptide (Fig. 1)Citation . This indicates that in the P1A-transgenic mice, the immune response against the tumor is not against the P1A35–43 epitope. The cytotoxicity against J558-B7 exhibited by the TILs isolated from tumors in normal mice is ~2-fold more than that seen with the TIL from the P1A transgenic mice.



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  		Fig. 1. TIL from P1A transgenic mice do not recognize P1A35–43 but do recognize other tumor antigens on J558-B7. Freshly isolated TIL from P1A transgenic mice or wild-type control mice injected with J558-B7 were used as effectors in a 6-h 51Cr-release assay. Varying numbers of effectors were incubated with labeled targets: P388D1 incubated with P1A35–43 peptide; P388D1 incubated with influenza nucleoprotein (NP) peptide (negative control) or J558-B7. The data are representative of three different experiments.

 
A second approach confirmed our finding that no P1A35–43-reactive effector cells were detectable in the P1A transgenic mice. We used the enzyme-linked immunospot assay to quantitate P1A35–43-reactive effector cells present in transgenic and wild-type control mice, which had been injected with 5 x 106 J558-B7. This assay detects cells which have already been primed and can produce cytokines rapidly in response to in vitro antigen stimulation. Approximately 1 month after injection, the spleens were removed from the primed mice and naïve age-matched controls, and spleen cells were stimulated in vitro for 20 h with P1A35–43 peptide. Using paired mAbs against IFN{gamma}, we were able to measure how many cells produced IFN{gamma} in response to peptide stimulation, and it is clear from the data shown in Fig. 2Citation that the P1A transgenic mice, which had been injected previously with J558-B7, had few or no activated P1A-specific T cells in their spleen. Normal littermates, which have had J558-B7 tumor cells, however, produced significant amounts of IFN-{gamma} in response to antigen stimulation.



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  		Fig. 2. P1A transgenic mice fail to produce detectable P1A35–43-specific IFN{gamma}-producing cells. P1A transgenic (P1A TG) and wild-type (WT) mice were injected with J558-B7, and 3–4 weeks later, spleens were removed from the primed and naïve age-matched controls. The spleen cells were incubated for 20 h in vitro in the presence or absence of P1A35–43 peptide, and production of IFN{gamma} was measured by enzyme-linked immunospot assay. Three experiments are shown in a–c. n.d., means not determined.

 
The almost complete tolerance to P1A in P1A-transgenic mice allows us to determine whether P1A reactivity is essential for rejection of J558 tumors. P1A transgenic and wild-type mice were injected with 5 x 106 J558-B7, and tumor incidence was recorded every other day. The data summarized in Table 1Citation demonstrate that these mice are equally capable of rejecting J558-B7 tumors.


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  		Table 1 Tumor incidence in P1A transgenic micea

 
We have reported previously that B7-1 transfected, but not vector-transfected J558 cells, were rejected in high proportion of syngeneic mice (25) . Here, we examined the growth kinetics of the J558-B7 tumors in the P1A transgenic mice. Both transgenic and control mice were injected with 5 x 106 J558-B7, and tumor diameters were measured every other day. As seen in Fig. 3Citation , the P1A transgenic mice rejected the J558-B7 tumors at the similar rate as the wild-type mice. However, a small contribution of P1A-reactive T cells cannot be ruled out as the tumors developed in the P1A transgenic animals were generally larger before rejection than those developed in the wild-type animals. Nevertheless, when we consider the ability of the P1A transgenic animals to effectively reject the J558-B7 tumors in the absence of P1A35–43-specific effectors (Table 1)Citation , it is clear that P1A35–43 is not a necessary rejection antigen for J558-B7.



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  		Fig. 3. J558-B7 tumor growth kinetics in P1A transgenic mice. P1A transgenic mice and wild-type control mice were injected with 5 x 106 J558-B7 in the left inguen. Tumor diameter was measured and recorded daily after the appearance of palpable tumors. Growth kinetics of individual tumors are shown. Each line depicts growth kinetics of a single tumor. Data are representative of four experiments.

 
2. In the Presence of P1A-reactive T-cell Response, J558 Can Evade Immune Therapy without Losing Susceptibility to Cytolysis by P1A-specific T Cells.
We have recently established when T cells transgenic for either TCR{alpha}ß or TCR{alpha} chain from P1A-specific CTL clones were used for adoptive therapy of large B7-1- J558 tumors, tumor cells can evade the P1A-specific T-cell response by antigenic drift via mutation of the P1A antigenic epitope (18) . Although this study demonstrated that the P1A antigen can serve as a tumor rejection antigen when specific T cells are present at levels that are significantly higher than those under physiological conditions, it remains to be determined whether the P1A-reactive T cells among immune spleen cells are sufficient to cause tumor rejection. We reasoned that if this were the case, the tumor cells must lose the P1A epitope to escape the immunity.

As shown in Fig. 4aCitation , spleen cells from the mice that rejected the J558-B7 tumors have significantly elevated levels of P1A-reactive T cells. Approximately 3–8% of spleen CD8 T cells recognized the P1A peptide bound to H-2Ld, as revealed by the flow cytometric analysis using the P1A:H-2Ld dimer. We adoptively transferred the immune spleen cells into RAG-2(-/-) BALB/c mice that bore J558-Neo tumors of 1.5–2 cm in diameter. The J558-B7-primed spleen cells caused rapid shrinkage of the J558-Neo tumors. However, the tumor regression was incomplete, and the tumor recurred and grew progressively (Fig. 4b)Citation .



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  		Fig. 4. J558-B7 immune spleens have a high frequency of P1A-reactive T cells and cause transient regression of large J558-Neo tumors in RAG-2(-/-) mice. J558-Neo tumor cells inoculated into the RAG-2(-/-) BALB/c mice. At 18 days after inoculation when the tumors reached 1.5–2 cm in diameter, the tumor-bearing mice received 50 x 106 J558-B7 immune spleen cells. a, frequency of the P1A-reactive T cells in spleens of J558-B7 immunized mice. Spleen cells were stained with anti-CD8 mAb in conjunction with either control (an H-2Ld-binding peptide from mouse cytomegalovirus) or P1A peptide-loaded H-2Ld dimers. Data shown are representative of four spleens that were pooled and used for the adoptive therapy. b, growth kinetics of large J558-Neo tumors after adoptive therapy with J558-B7 immune spleen cells. Data shown are means and SD of the tumor diameter in a group of six tumors.

 
To understand the mechanism of tumor evasion, we first determined whether the P1A-reactive T cells were present in the tumors. We isolated TILs by depleting the tumor cells using PC-1-specific antibody, as described (26) . The TILs were stained with anti-CD8 mAb in conjunction with peptide-loaded H-2Ld dimer. As shown in Fig. 5Citation , the TIL from the recurrent tumors have ~3% of P1A-reactive T cells, which account for ~5% of CD8 T cells in the tumors. Thus, tumor growth was not a result of death of P1A-reactive T cells. However, because the frequency of P1A-reactive T cells is similar to the cells transferred in the first place (6.7% of the CD8 T cells), there was no preferential accumulation and/or expansion of P1A reactive T cells into the tumor environment.



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  		Fig. 5. Presence of P1A-reactive CD8 T cells among the TIL from recurrent tumors. TIL isolated from tumors harvested at 4 weeks after adoptive therapy were stained with anti-CD8 mAb in conjunction with either control- or P1A peptide-loaded H-2Ld dimers. Data shown are representative of two independent isolations of TIL.

 
We have demonstrated that J558-B7 tumors can down-regulate their cell surface MHC to evade T-cell destruction (28 , 29) . To test whether MHC class I was down-regulated, we analyzed the expression of cell surface H-2Ld, the restriction element of the P1A-reactive T cells. As shown in Fig. 6aCitation , all four independent isolates of recurrent tumors have high cell surface H-2Ld, which is comparable with the parental tumor cells.



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  		Fig. 6. a, expression of the cell surface H-2Ld on four independent isolates of recurrent tumors. Data shown are histograms depicting binding to either isotype controls (dashed lines) or anti-H-2Ld (continuous lines) antibodies. Black line, expression of H-2Ld by J558-Neo tumor cells grown in the absence of T-cell selection (JJ), whereas the four gray lines depict H-2Ld expression of the recurrent tumor lines, #1–4. b, cytolysis of the recurrent tumor cells by activated P1A-reactive transgenic T cells. Transgenic T cells with P1A-reactive TCR were stimulated in vitro with P1A peptide for 4 days and used as effectors. Tumor cells isolated from either recurrent tumors (Tum#1–4) or tumor cells from untreated mice (JJ) were used as target cells. Data shown are representative of two independent experiments.

 
We have recently demonstrated that in mice that are treated with transgenic T cells expressing either TCR{alpha} or TCR{alpha}ß from a P1A-reactive CTL clone, tumor resistance to T-cell therapy was associated with mutation of P1A-antigenic epitope (18) . To test if this is responsible for tumor recurrence in mice that received spleen cells from mice immunized with J558-B7, we cloned the P1A gene fragment encompassing the P1A epitope. Multiple P1A DNA clones were isolated and sequenced. As shown in Table 2Citation , none of the P1A clones contain mutations in the P1A antigenic epitope. This is in sharp contrast to the mice that received monoclonal transgenic T cells, where 65 of 68 clones isolated from two recurrent tumors contained mutations in the P1A gene. The cells from the three remaining clones that harbored the unmutated allele did not seem to express it. As we have reported, all mutations disrupted T-cell recognition of the tumor cells (18) .


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  		Table 2 Lack of mutations in the P1A epitope among tumor cells that evaded J558-B7 immune spleen cellsa

 
Consistent with the normal cell surface expression of H-2Ld and lack of mutation in P1A genes, we found that the recurrent tumor cells were as susceptible to cytolysis by P1CTL as the tumor cells isolated from tumors that grew in RAG-2(-/-) mice receiving no T-cell therapy (Fig. 6b)Citation . Taken together, our results demonstrated that in mice with a polyclonal T-cell repertoire, loss of reactivity to P1A-reactive T cells was not necessary for tumor evasion in vivo.


   DISCUSSION
Top
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
REFERENCES
 
We have demonstrated in this study that tolerance to P1A antigen does not prevent CD8-T cell-mediated protection from B7-1-transfected J558 cells. The simplest explanation is that although P1A is a major tumor antigen in the J558 cells, the tumor cells may express other tumor antigens that are more important for tumor rejection. Indeed, although the P1A transgenic mice did not mount detectable CTL response against the P1A epitope, significant tumor-reactive CTL can be found within tumors in these mice. Although the principle of multiplicity of tumor antigen is well established (30) , the lack of difference in tumor incidence and growth kinetics argues that at least for J558 tumor cells, P1A-reactive CTL does not play a significant role in tumor rejection. Nevertheless, tolerance to P1A appears to have resulted in somewhat delayed tumor rejection (Fig. 3)Citation . These data suggested immune response to P1A may facilitate immune response to other tumor antigens.

Conversely, in mice that received J558-B7 immune spleen cells, tumor recurrence is not associated with mutations of the P1A antigen. Because a significant number of P1A-reactive T cells are observed in these mice, P1A-reactive T cells and P1A-expressing tumor cells can coexist in vivo. Although coexistence between T cells and their target cancer cells has been reported in human cancers (31 , 32) , it is not clear whether the tumor antigens are altered or lost. Taken together, our data argue that P1A-reactive T cells are neither necessary nor sufficient to convey immune protection in mice with normal T-cell repertoire, and therefore, P1A should not be considered as a major tumor rejection antigen.

Several observations in this area deserve careful consideration.

First, immunization with a P1A-transfected tumor cell line, but not the untransfected tumor cells, results in a significant, albeit partial, protection to subsequent challenge with the P815 tumor cells (11) . However, several groups have reported that the strength of P1A-specific CTL response does not correspond to the degree of immune protection. Thus, vaccinia virus-expressing P1A (33) , and peptides consisting of both helper and CTL epitopes in P1A (13) failed to induce protection despite significant priming of P1A-reactive T cells. On balance, although a beneficial effect of P1A immunization has been demonstrated, it is unclear whether P1A-reactive CTL induction is essential for immune protection.

Second, when naive P1A-reactive transgenic T cells are adoptively transferred into an immune deficient host, they appear to convey significant protection, although they fail to mediate complete rejection of large tumors unless the tumors expressed costimulatory molecules, such as B7-1, B7DC/PDL-2, or B7H (20, 21, 22) . The ability of transgenic T cells, but not nontransgenic polyclonal T cells, to select for antigenic variants in vivo deserves further comment. It is possible that because P1A-reactive T cells are not fully competent in tumor rejection, P1A-reactive T cells need to be completely dominant to convey immune protection. Simultaneous immune response targeted at other tumor antigens, because of immune dominance, may have prevented full amplification of P1A-reactive T cells. Indeed, we found no selective expansion of P1A-reactive T cells in the tumor-bearing mice after adoptive transfer of J558-B7 immune spleen cells.

P1A, as the first tumor antigen to be identified, has several interesting immunological properties. Although it was initially reported to be specifically expressed in mastocytoma P815 (2) , we reported that P1A is expressed in multiple lineages of tumor cells, including plasmacytoma, fibrosarcoma, in addition to mastocytoma (23) . Moreover, P1A is also expressed in normal tissues, including placenta, testis, spleen, and thymic medullar epithelial cells (24 , 34 , 35) . Given the fact that thymic medullar epithelial cells can induce immune tolerance, the expression of P1A genes in normal tissues may provide an explanation for both the poor immune protection of P1A-reactive cells and the lack of severe autoimmunity associated with these antigens.

Finally, it should be noted the basic feature of limited expression of P1A antigen in normal tissues is representative of most of the unmutated tumor antigens identified to date. It is therefore likely that the limited capacity of P1A to induce tumor rejection in mice with an unperturbed TCR repertoire may prove to be the rule rather than exception. Nevertheless, because the unmutated tumor antigens are more broadly distributed among tumors of different lineages and the same lineages of tumors in different patients, it would be of great importance to explore approaches that can potentially alter the TCR repertoire to allow more efficient tumor rejection based on the unmutated tumor antigens.


   ACKNOWLEDGMENTS
 
We thank Lynde Shaw for editorial assistance.


   FOOTNOTES
 
The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

1 Supported by NIH Grants CA58033, CA69091, CA82355, and AI51342. Part of the study was carried out at the New York University Medical Center. Back

2 S. S. and X-F. B. contributed equally to this study. Back

3 Present address: 46 Northview Avenue, Montclair, NJ 07043. Back

4 To whom requests for reprints should be addressed, at 129 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210. Phone: (614) 292-3054; Fax: (614) 688-8152; E-mail: liu-3{at}medctr.osu.edu Back

5 The abbreviations used are: mAb, monoclonal antibody; TCR, T-cell receptor; TIL, tumor-infiltrating lymphocyte. Back

Received 3/14/03. Revised 6/17/03. Accepted 7/ 9/03.


   REFERENCES
Top
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 

  1. Prehn R. T., Main J. M. Immunity to methylcholanthrene-induced sarcomas. J. Natl. Cancer Inst. (Bethesda), 18: 769-778, 1957.
  2. Van den Eynde B., Lethe B., Van Pel A., De Plaen E., Boon T. The gene coding for a major tumor rejection antigen of tumor P815 is identical to the normal gene of syngeneic DBA/2 mice. J. Exp. Med., 173: 1373-1384, 1991.[Abstract/Free Full Text]
  3. Monach P. A., Meredith S. C., Siegel C. T., Schreiber H. A unique tumor antigen produced by a single amino acid substitution. Immunity, 2: 45-59, 1995.[Medline]
  4. Dubey P., Hendrickson R. C., Meredith S. C., Siegel C. T., Shabanowitz J., Skipper J. C., Engelhard V. H., Hunt D. F., Schreiber H. The immunodominant antigen of an ultraviolet-induced regressor tumor is generated by a somatic point mutation in the DEAD box helicase p68. J. Exp. Med., 185: 695-705, 1997.[Abstract/Free Full Text]
  5. Wang Y. C., Zhu L., McHugh R., Graham S. D., Jr., Hillyer C. D., Dillehay D., Sell K. W., Selvaraj P. Induction of autologous tumor-specific cytotoxic T-lymphocyte activity against a human renal carcinoma cell line by B7–1 (CD8O) costimulation. J. Immunother. Emphasis Tumor Immunol., 19: 1-8, 1996.[Medline]
  6. Wolfel T., Hauer M., Schneider J., Serrano M., Wolfel C., Klehmann-Hieb E., De Plaen E., Hankeln T., Meyer zum Buschenfelde K. H., Beach D. A p16INK4a-insensitive CDK4 mutant targeted by cytolytic T lymphocytes in a human melanoma. Science (Wash. DC), 269: 1281-1284, 1995.[Abstract/Free Full Text]
  7. Wolfel T., Van Pel A., Brichard V., Schneider J., Seliger B., Meyer zum Buschenfelde K. H., Boon T. Two tyrosinase nonapeptides recognized on HLA-A2 melanomas by autologous cytolytic T lymphocytes. Eur. J. Immunol., 24: 759-764, 1994.[Medline]
  8. Boon T., Cerottini J. C., Van den Eynde B., van der Bruggen P., Van Pel A. Tumor antigens recognized by T lymphocytes. Annu. Rev. Immunol., 12: 337-365, 1994.[Medline]
  9. Boon T., De Plaen E., Lurquin C., Van den Eynde B., van der Bruggen P., Traversari C., Amar-Costesec A., Van Pel A. Identification of tumour rejection antigens recognized by T lymphocytes. Cancer Surv., 13: 23-37, 1992.[Medline]
  10. Mumberg D., Monach P. A., Wanderling S., Philip M., Toledano A. Y., Schreiber R. D., Schreiber H. CD4(+) T cells eliminate MHC class II-negative cancer cells in vivo by indirect effects of IFN-gamma. Proc. Natl. Acad. Sci. USA, 96: 8633-8638, 1999.[Abstract/Free Full Text]
  11. Brandle D., Bilsborough J., Rulicke T., Uyttenhove C., Boon T., Van den Eynde B. J. The shared tumor-specific antigen encoded by mouse gene P1A is a target not only for cytolytic T lymphocytes but also for tumor rejection. Eur. J. Immunol., 28: 4010-4019, 1998.[Medline]
  12. Overwijk W. W., Tsung A., Irvine K. R., Parkhurst M. R., Goletz T. J., Tsung K., Carroll M. W., Liu C., Moss B., Rosenberg S. A., Restifo N. P. gp100/pmel 17 is a murine tumor rejection antigen: induction of "self"- reactive, tumoricidal T cells using high-affinity, altered peptide ligand. J. Exp. Med., 188: 277-286, 1998.[Abstract/Free Full Text]
  13. McCabe B. J., Irvine K. R., Nishimura M. I., Yang J. C., Spiess P. J., Shulman E. P., Rosenberg S. A., Restifo N. P. Minimal determinant expressed by a recombinant vaccinia virus elicits therapeutic antitumor cytolytic T lymphocyte responses. Cancer Res., 55: 1741-1747, 1995.[Abstract/Free Full Text]
  14. Brandle D., Brasseur F., Weynants P., Boon T., Van den Eynde B. A mutated HLA-A2 molecule recognized by autologous cytotoxic T lymphocytes on a human renal cell carcinoma. J. Exp. Med., 183: 2501-2508, 1996.[Abstract/Free Full Text]
  15. Rosenberg S. A., Yang J. C., Schwartzentruber D. J., Hwu P., Marincola F. M., Topalian S. L., Restifo N. P., Dudley M. E., Schwarz S. L., Spiess P. J., Wunderlich J. R., Parkhurst M. R., Kawakami Y., Seipp C. A., Einhorn J. H., White D. E. Immunologic and therapeutic evaluation of a synthetic peptide vaccine for the treatment of patients with metastatic melanoma. Nat. Med., 4: 321-327, 1998.[Medline]
  16. Zeh H. J., III, Perry-Lalley D., Dudley M. E., Rosenberg S. A., Yang J. C. High avidity CTLs for two self-antigens demonstrate superior in vitro and in vivo antitumor efficacy. J. Immunol., 162: 989-994, 1999.[Abstract/Free Full Text]
  17. Yang G., Hellstrom K. E., Mizuno M. T., Chen L. In vitro priming of tumor-reactive cytolytic T lymphocytes by combining IL-10 with B7-CD28 costimulation. J. Immunol., 155: 3897-3903, 1995.[Abstract]
  18. Bai X. F., Liu J., Li O., Zheng P., Liu Y. Antigenic drift as a mechanism for tumor evasion of destruction by cytolytic T lymphocytes. J. Clin. Investig., 111: 1487-1496, 2003.[Medline]
  19. Lehmann P. V., Forsthuber T., Miller A., Sercarz E. E. Spreading of T-cell autoimmunity to cryptic determinants of an autoantigen. Nature (Lond.), 358: 155-157, 1992.[Medline]
  20. Bai X. F., Bender J., Liu J., Zhang H., Wang Y., Li O., Du P., Zheng P., Liu Y. Local costimulation reinvigorates tumor-specific cytolytic T lymphocytes for experimental therapy in mice with large tumor burdens. J. Immunol., 167: 3936-3943, 2001.[Abstract/Free Full Text]
  21. Liu X., Bai X. F., Wen J., Gao J-X., Liu J., Lu P., Wang Y., Zheng P., Liu Y. B7H costimulates clonal expansion of, and cognate destruction of tumor cells by, CD8+ T lymphocytes in vivo. J. Exp. Med., 194: 1339-1348, 2001.[Abstract/Free Full Text]
  22. Liu X., Gao J-X., Wen J., Yin J., Li O., Zuo T., Gajewski T. F., Fu Y-X., Zheng P., Liu L. B7DC/PDL2 promotes tumor immunity by a PD-1–independent mechanism. J. Exp. Med., 197: 1721-1730, 2003.[Abstract/Free Full Text]
  23. Ramarathinam L., Sarma S., Maric M., Zhao M., Yang G., Chen L., Liu Y. Multiple lineages of tumors express a common tumor antigen, P1A, but they are not cross-protected. J. Immunol., 155: 5323-5329, 1995.[Abstract]
  24. Sarma S., Guo Y., Guilloux Y., Lee C., Bai X-F., Liu Y. Cytotoxic T lymphocytes to an unmutated tumor antigen P1A: normal development but restrained effector function. J. Exp. Med., 189: 811-820, 1999.[Abstract/Free Full Text]
  25. Ramarathinam L., Castle M., Wu Y., Liu Y. T cell costimulation by B7/BB1 induces CD8 T cell-dependent tumor rejection: an important role of B7/BB1 in the induction, recruitment, and effector function of antitumor T cells. J. Exp. Med., 179: 1205-1214, 1994.[Abstract/Free Full Text]
  26. Maric M., Zheng P., Sarma S., Guo Y., Liu Y. Maturation of cytotoxic T lymphocytes against a B7-transfected nonmetastatic tumor: a critical role for costimulation by B7 on both tumor and host antigen-presenting cells. Cancer Res., 58: 3376-3384, 1998.[Abstract/Free Full Text]
  27. Gao J-X., Zhang H., Bai X. F., Wen J., Zheng X., Liu J., Zheng P., Liu Y. Peripheral blockade of B7–1 and B7–2 inhibits clonal deletion of highly pathogenic autoreactive T cells. J. Exp. Med., 195: 959-971, 2002.[Abstract/Free Full Text]
  28. Zheng P., Guo Y., Niu Q., Levy D. E., Dyck J. A., Lu S., Sheiman L. A., Liu Y. Proto-oncogene PML controls genes devoted to MHC class I antigen presentation. Nature (Lond.), 396: 373-376, 1998.[Medline]
  29. Zheng P., Sarma S., Guo Y., Liu Y. Two mechanisms for tumor evasion of preexisting cytotoxic T-cell responses: lessons from recurrent tumors. Cancer Res., 59: 3461-3467, 1999.[Abstract/Free Full Text]
  30. Wortzel R. D., Philipps C., Schreiber H. Multiple tumour-specific antigens expressed on a single tumour cell. Nature (Lond.), 304: 165-167, 1983.[Medline]
  31. Lee P. P., Yee C., Savage P. A., Fong L., Brockstedt D., Weber J. S., Johnson D., Swetter S., Thompson J., Greenberg P. D., Roederer M., Davis M. M. Characterization of circulating T cells specific for tumor-associated antigens in melanoma patients. Nat. Med., 5: 677-685, 1999.[Medline]
  32. Romero P., Dunbar P. R., Valmori D., Pittet M., Ogg G. S., Rimoldi D., Chen J. L., Lienard D., Cerottini J. C., Cerundolo V. Ex vivo staining of metastatic lymph nodes by class I major histocompatibility complex tetramers reveals high numbers of antigen-experienced tumor-specific cytolytic T lymphocytes. J. Exp. Med., 188: 1641-1650, 1998.[Abstract/Free Full Text]
  33. Irvine K. R., McCabe B. J., Rosenberg S. A., Restifo N. P. Synthetic oligonucleotide expressed by a recombinant vaccinia virus elicits therapeutic CTL. J. Immunol., 154: 4651-4657, 1995.[Abstract]
  34. Uyttenhove C., Godfraind C., Lethe B., Amar-Costesec A., Renauld J. C., Gajewski T. F., Duffour M. T., Warnier G., Boon T., Van den Eynde B. J. The expression of mouse gene P1A in testis does not prevent safe induction of cytolytic T cells against a P1A-encoded tumor antigen. Int. J. Cancer, 70: 349-356, 1997.[Medline]
  35. Derbinski J., Schulte A., Kyewski B., Klein L. Promiscuous gene expression in medullary thymic epithelial cells mirrors the peripheral self. Nat. Immunol., 2: 1032-1039, 2001.[Medline]




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