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The vitronectin receptor and its associated CD47 molecule mediates proinflammatory cytokine synthesis in human monocytes by interaction with soluble CD23.

Hermann P, Armant M, Brown E, Rubio M, Ishihara H, Ulrich D, Caspary RG, Lindberg FP, Armitage R, Maliszewski C, Delespesse G, Sarfati M - J. Cell Biol. (1999)

Bottom Line: Surprisingly, anti-CD47 and beta3 mAbs do not block sCD23 binding to alphav+beta3+ T cell lines, whereas Vn and an alphav mAb (clone AMF7) do inhibit sCD23 binding, suggesting the VnR complex may be a functional receptor for sCD23. sCD23 directly binds alphav+beta3+/CD47(-) cell lines, but coexpression of CD47 increases binding.Moreover, sCD23 binds purified alphav protein and a single human alphav chain CHO transfectant.We conclude that the VnR and its associated CD47 molecule may function as a novel receptor for sCD23 to mediate its proinflammatory activity and, as such, may be involved in the inflammatory process of the immune response.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire Allergie, Centre de recherch¿e Louis-Charles Simard, Pavillon Notre-Dame, Centre Hospitalier Université de Montréal (CHUM), Montreal, Quebec H2L 4M1, Canada.

ABSTRACT
The vitronectin receptor, alphavbeta3 integrin, plays an important role in tumor cell invasion, angiogenesis, and phagocytosis of apoptotic cells. CD47, a member of the multispan transmembrane receptor family, physically and functionally associates with vitronectin receptor (VnR). Although vitronectin (Vn) is not a ligand of CD47, anti-CD47 and beta3 mAbs suppress Vn, but not fibronectin (Fn) binding and function. Here, we show that anti-CD47, anti-beta3 mAb and Vn, but not Fn, inhibit sCD23-mediated proinflammatory function (TNF-alpha, IL-12, and IFN-gamma release). Surprisingly, anti-CD47 and beta3 mAbs do not block sCD23 binding to alphav+beta3+ T cell lines, whereas Vn and an alphav mAb (clone AMF7) do inhibit sCD23 binding, suggesting the VnR complex may be a functional receptor for sCD23. sCD23 directly binds alphav+beta3+/CD47(-) cell lines, but coexpression of CD47 increases binding. Moreover, sCD23 binds purified alphav protein and a single human alphav chain CHO transfectant. We conclude that the VnR and its associated CD47 molecule may function as a novel receptor for sCD23 to mediate its proinflammatory activity and, as such, may be involved in the inflammatory process of the immune response.

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Binding of sCD23 to  CD47+ and CD47− cell lines.  CD47+ and CD47− cell lines  were stained with two anti-CD47 mAbs (clone 10G2 and  B6H12), anti-αv (CD51) and  anti-β3 (CD61) mAbs, or  B-sCD23 as described in Materials and Methods. OV10 carcinoma and Jurkat cell lines express different levels of αv  (CD51) chain which correlate  with sCD23 binding.
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Figure 8: Binding of sCD23 to CD47+ and CD47− cell lines. CD47+ and CD47− cell lines were stained with two anti-CD47 mAbs (clone 10G2 and B6H12), anti-αv (CD51) and anti-β3 (CD61) mAbs, or B-sCD23 as described in Materials and Methods. OV10 carcinoma and Jurkat cell lines express different levels of αv (CD51) chain which correlate with sCD23 binding.

Mentions: To further support the hypothesis that sCD23 may directly interact with αv chain of the trimolecular complex, we prepared CHO transfectants singly expressing human αv chain (CHO-CD51). The results in Fig. 7 demonstrated sCD23 strongly bound to CHO-CD51 compared to untransfected cell line. Although CHO-CD51 transfectant did not express human β3 (CD61) chain, CHO cell lines were reported to express rodent β chain integrins (Lindberg et al., 1993) which likely associated with the human αv chain underlying the successful stable expression of a single human integrin chain. Nevertheless, CHO cells also expressed hamster CD47 which might contribute to sCD23 binding to αv/CD51 on live cells as reported for Vn binding to untransfected CHO cells (Lindberg et al., 1993). To directly assess whether CD47 expression was required for sCD23 interaction with αv/CD51, we examined sCD23 binding to human CD47 deficient cell lines. As shown in Fig. 8, sCD23 bound to OV10 ovarian carcinoma VnR+/CD47− cell line demonstrating that CD47 was dispensable for sCD23 binding. Coexpression of CD47 further increased its binding. A similar effect was seen on transfection of CD47− Jurkat with CD47 (data not shown).


The vitronectin receptor and its associated CD47 molecule mediates proinflammatory cytokine synthesis in human monocytes by interaction with soluble CD23.

Hermann P, Armant M, Brown E, Rubio M, Ishihara H, Ulrich D, Caspary RG, Lindberg FP, Armitage R, Maliszewski C, Delespesse G, Sarfati M - J. Cell Biol. (1999)

Binding of sCD23 to  CD47+ and CD47− cell lines.  CD47+ and CD47− cell lines  were stained with two anti-CD47 mAbs (clone 10G2 and  B6H12), anti-αv (CD51) and  anti-β3 (CD61) mAbs, or  B-sCD23 as described in Materials and Methods. OV10 carcinoma and Jurkat cell lines express different levels of αv  (CD51) chain which correlate  with sCD23 binding.
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2132927&req=5

Figure 8: Binding of sCD23 to CD47+ and CD47− cell lines. CD47+ and CD47− cell lines were stained with two anti-CD47 mAbs (clone 10G2 and B6H12), anti-αv (CD51) and anti-β3 (CD61) mAbs, or B-sCD23 as described in Materials and Methods. OV10 carcinoma and Jurkat cell lines express different levels of αv (CD51) chain which correlate with sCD23 binding.
Mentions: To further support the hypothesis that sCD23 may directly interact with αv chain of the trimolecular complex, we prepared CHO transfectants singly expressing human αv chain (CHO-CD51). The results in Fig. 7 demonstrated sCD23 strongly bound to CHO-CD51 compared to untransfected cell line. Although CHO-CD51 transfectant did not express human β3 (CD61) chain, CHO cell lines were reported to express rodent β chain integrins (Lindberg et al., 1993) which likely associated with the human αv chain underlying the successful stable expression of a single human integrin chain. Nevertheless, CHO cells also expressed hamster CD47 which might contribute to sCD23 binding to αv/CD51 on live cells as reported for Vn binding to untransfected CHO cells (Lindberg et al., 1993). To directly assess whether CD47 expression was required for sCD23 interaction with αv/CD51, we examined sCD23 binding to human CD47 deficient cell lines. As shown in Fig. 8, sCD23 bound to OV10 ovarian carcinoma VnR+/CD47− cell line demonstrating that CD47 was dispensable for sCD23 binding. Coexpression of CD47 further increased its binding. A similar effect was seen on transfection of CD47− Jurkat with CD47 (data not shown).

Bottom Line: Surprisingly, anti-CD47 and beta3 mAbs do not block sCD23 binding to alphav+beta3+ T cell lines, whereas Vn and an alphav mAb (clone AMF7) do inhibit sCD23 binding, suggesting the VnR complex may be a functional receptor for sCD23. sCD23 directly binds alphav+beta3+/CD47(-) cell lines, but coexpression of CD47 increases binding.Moreover, sCD23 binds purified alphav protein and a single human alphav chain CHO transfectant.We conclude that the VnR and its associated CD47 molecule may function as a novel receptor for sCD23 to mediate its proinflammatory activity and, as such, may be involved in the inflammatory process of the immune response.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire Allergie, Centre de recherch¿e Louis-Charles Simard, Pavillon Notre-Dame, Centre Hospitalier Université de Montréal (CHUM), Montreal, Quebec H2L 4M1, Canada.

ABSTRACT
The vitronectin receptor, alphavbeta3 integrin, plays an important role in tumor cell invasion, angiogenesis, and phagocytosis of apoptotic cells. CD47, a member of the multispan transmembrane receptor family, physically and functionally associates with vitronectin receptor (VnR). Although vitronectin (Vn) is not a ligand of CD47, anti-CD47 and beta3 mAbs suppress Vn, but not fibronectin (Fn) binding and function. Here, we show that anti-CD47, anti-beta3 mAb and Vn, but not Fn, inhibit sCD23-mediated proinflammatory function (TNF-alpha, IL-12, and IFN-gamma release). Surprisingly, anti-CD47 and beta3 mAbs do not block sCD23 binding to alphav+beta3+ T cell lines, whereas Vn and an alphav mAb (clone AMF7) do inhibit sCD23 binding, suggesting the VnR complex may be a functional receptor for sCD23. sCD23 directly binds alphav+beta3+/CD47(-) cell lines, but coexpression of CD47 increases binding. Moreover, sCD23 binds purified alphav protein and a single human alphav chain CHO transfectant. We conclude that the VnR and its associated CD47 molecule may function as a novel receptor for sCD23 to mediate its proinflammatory activity and, as such, may be involved in the inflammatory process of the immune response.

Show MeSH
Related in: MedlinePlus