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B7H costimulates clonal expansion of, and cognate destruction of tumor cells by, CD8(+) T lymphocytes in vivo.

Liu X, Bai XF, Wen J, Gao JX, Liu J, Lu P, Wang Y, Zheng P, Liu Y - J. Exp. Med. (2001)

Bottom Line: B7H/B7RP (hereby called B7H) is a new member of the B7 family of costimulatory molecules and interacts with inducible costimulatory molecule (ICOS).Its function for CD8 T cells has not been reported.Taken together, our results reveal that B7H costimulates clonal expansion of, and cognate destruction by CD8(+) T lymphocytes in vivo.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology and Comprehensive Cancer Center, Ohio State University Medical Center, Columbus, OH 43210, USA.

ABSTRACT
B7H/B7RP (hereby called B7H) is a new member of the B7 family of costimulatory molecules and interacts with inducible costimulatory molecule (ICOS). Its function for CD8 T cells has not been reported. We report here that expression of B7H on the tumor cells reduced tumorigenicity and induced immunity to subsequent challenge with parental tumor cells. The immune protection correlates with an enhanced cytotoxic T lymphocyte (CTL) response against P1A, the major tumor antigen expressed in the J558 tumor. To understand the mechanism of immune protection, we adoptively transferred transgenic T cells specific for tumor antigen P1A into mice that bore P1A-expressing tumors. We found that while the transgenic T cells divided faster in mice bearing the B7H(+) tumors, optimal B7H-induced clonal expansion of P1CTL required costimulation by B7-1 and B7-2 on the endogenous host antigen-presenting cells (APCs). Interestingly, when B7H(+) and B7H(-) tumors were coinjected, P1CTL selectively eliminated the B7H(+) tumor cells. Moreover, B7H expressed on the tumor cells made them highly susceptible to destruction by CTL in vivo, even if the CTL was administrated into mice with large tumor burdens. Tumors that recurred in the P1CTL-treated mice lost transfected B7H and/or H-2L(d), the class I molecule that presents the P1A peptide. Taken together, our results reveal that B7H costimulates clonal expansion of, and cognate destruction by CD8(+) T lymphocytes in vivo.

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Generation of tumor cell lines expressing B7H-GFP fusion protein. (A) Intensity of green fluorescence in J558 cells transfected with vector alone (J558-Neo) or B7H-GFP. Profiles of three independent clones were presented. These clones were cultured separately, mixed at an 1:1:1 ratio, and used in all subsequent experiments. (B) ICOSIg binds to J558-B7H, but not to J558-Neo. The J558-transfectants were incubated with either human IgG1Fc or ICOSIg (50 μg/ml), and the binding was measured by flow cytometry. (C) Susceptibility of J558-B7H, J558-Neo, and J558-B7 to transgenic P1CTL, which had been stimulated in vitro for 4 d with P1A peptide (0.1 μg/ml). Two independent experiments were presented. Unpulsed or P1A-pulsed P388D1(H-2d) target cells were used as negative and positive controls, respectively.
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fig1: Generation of tumor cell lines expressing B7H-GFP fusion protein. (A) Intensity of green fluorescence in J558 cells transfected with vector alone (J558-Neo) or B7H-GFP. Profiles of three independent clones were presented. These clones were cultured separately, mixed at an 1:1:1 ratio, and used in all subsequent experiments. (B) ICOSIg binds to J558-B7H, but not to J558-Neo. The J558-transfectants were incubated with either human IgG1Fc or ICOSIg (50 μg/ml), and the binding was measured by flow cytometry. (C) Susceptibility of J558-B7H, J558-Neo, and J558-B7 to transgenic P1CTL, which had been stimulated in vitro for 4 d with P1A peptide (0.1 μg/ml). Two independent experiments were presented. Unpulsed or P1A-pulsed P388D1(H-2d) target cells were used as negative and positive controls, respectively.

Mentions: As no anti-B7H mAb is available at this point, we have produced a fusion gene encoding a B7H-GFP chimera protein which can be easily quantitated by flow cytometry. The plasmid containing B7H-GFP was therefore used to transfect the J558 cells. After selection with G418, the drug resistant clones were screened by flow cytometry. Three independent clones were selected for the current studies. As shown in Fig. 1 A, all three clones expressed significant levels of B7H-GFP. Fusion with GFP did not abrogate the function of B7H as the J558-B7H-GFP can bind to ICOSIg (Fig. 1 B). Moreover, the B7H-GFP is expressed on the cell surface as revealed by confocal microscopy (data not shown). To avoid variation of individual clones, we maintained the clones individually, but mixed equal numbers of cells from the three clones for all the experiments described in the current study. As shown in Fig. 1 C, both J558-Neo and J558-B7H expressed and presented the tumor antigen P1A as they were readily killed by P1A-specific transgenic T cells. While B7–1 significantly increased lysis of J558 cells by CTL as we have described (12), B7H did not substantially enhance the lysis by P1CTL in vitro.


B7H costimulates clonal expansion of, and cognate destruction of tumor cells by, CD8(+) T lymphocytes in vivo.

Liu X, Bai XF, Wen J, Gao JX, Liu J, Lu P, Wang Y, Zheng P, Liu Y - J. Exp. Med. (2001)

Generation of tumor cell lines expressing B7H-GFP fusion protein. (A) Intensity of green fluorescence in J558 cells transfected with vector alone (J558-Neo) or B7H-GFP. Profiles of three independent clones were presented. These clones were cultured separately, mixed at an 1:1:1 ratio, and used in all subsequent experiments. (B) ICOSIg binds to J558-B7H, but not to J558-Neo. The J558-transfectants were incubated with either human IgG1Fc or ICOSIg (50 μg/ml), and the binding was measured by flow cytometry. (C) Susceptibility of J558-B7H, J558-Neo, and J558-B7 to transgenic P1CTL, which had been stimulated in vitro for 4 d with P1A peptide (0.1 μg/ml). Two independent experiments were presented. Unpulsed or P1A-pulsed P388D1(H-2d) target cells were used as negative and positive controls, respectively.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2195972&req=5

fig1: Generation of tumor cell lines expressing B7H-GFP fusion protein. (A) Intensity of green fluorescence in J558 cells transfected with vector alone (J558-Neo) or B7H-GFP. Profiles of three independent clones were presented. These clones were cultured separately, mixed at an 1:1:1 ratio, and used in all subsequent experiments. (B) ICOSIg binds to J558-B7H, but not to J558-Neo. The J558-transfectants were incubated with either human IgG1Fc or ICOSIg (50 μg/ml), and the binding was measured by flow cytometry. (C) Susceptibility of J558-B7H, J558-Neo, and J558-B7 to transgenic P1CTL, which had been stimulated in vitro for 4 d with P1A peptide (0.1 μg/ml). Two independent experiments were presented. Unpulsed or P1A-pulsed P388D1(H-2d) target cells were used as negative and positive controls, respectively.
Mentions: As no anti-B7H mAb is available at this point, we have produced a fusion gene encoding a B7H-GFP chimera protein which can be easily quantitated by flow cytometry. The plasmid containing B7H-GFP was therefore used to transfect the J558 cells. After selection with G418, the drug resistant clones were screened by flow cytometry. Three independent clones were selected for the current studies. As shown in Fig. 1 A, all three clones expressed significant levels of B7H-GFP. Fusion with GFP did not abrogate the function of B7H as the J558-B7H-GFP can bind to ICOSIg (Fig. 1 B). Moreover, the B7H-GFP is expressed on the cell surface as revealed by confocal microscopy (data not shown). To avoid variation of individual clones, we maintained the clones individually, but mixed equal numbers of cells from the three clones for all the experiments described in the current study. As shown in Fig. 1 C, both J558-Neo and J558-B7H expressed and presented the tumor antigen P1A as they were readily killed by P1A-specific transgenic T cells. While B7–1 significantly increased lysis of J558 cells by CTL as we have described (12), B7H did not substantially enhance the lysis by P1CTL in vitro.

Bottom Line: B7H/B7RP (hereby called B7H) is a new member of the B7 family of costimulatory molecules and interacts with inducible costimulatory molecule (ICOS).Its function for CD8 T cells has not been reported.Taken together, our results reveal that B7H costimulates clonal expansion of, and cognate destruction by CD8(+) T lymphocytes in vivo.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology and Comprehensive Cancer Center, Ohio State University Medical Center, Columbus, OH 43210, USA.

ABSTRACT
B7H/B7RP (hereby called B7H) is a new member of the B7 family of costimulatory molecules and interacts with inducible costimulatory molecule (ICOS). Its function for CD8 T cells has not been reported. We report here that expression of B7H on the tumor cells reduced tumorigenicity and induced immunity to subsequent challenge with parental tumor cells. The immune protection correlates with an enhanced cytotoxic T lymphocyte (CTL) response against P1A, the major tumor antigen expressed in the J558 tumor. To understand the mechanism of immune protection, we adoptively transferred transgenic T cells specific for tumor antigen P1A into mice that bore P1A-expressing tumors. We found that while the transgenic T cells divided faster in mice bearing the B7H(+) tumors, optimal B7H-induced clonal expansion of P1CTL required costimulation by B7-1 and B7-2 on the endogenous host antigen-presenting cells (APCs). Interestingly, when B7H(+) and B7H(-) tumors were coinjected, P1CTL selectively eliminated the B7H(+) tumor cells. Moreover, B7H expressed on the tumor cells made them highly susceptible to destruction by CTL in vivo, even if the CTL was administrated into mice with large tumor burdens. Tumors that recurred in the P1CTL-treated mice lost transfected B7H and/or H-2L(d), the class I molecule that presents the P1A peptide. Taken together, our results reveal that B7H costimulates clonal expansion of, and cognate destruction by CD8(+) T lymphocytes in vivo.

Show MeSH
Related in: MedlinePlus