Limits...
Opsonization of apoptotic cells by autologous iC3b facilitates clearance by immature dendritic cells, down-regulates DR and CD86, and up-regulates CC chemokine receptor 7.

Verbovetski I, Bychkov H, Trahtemberg U, Shapira I, Hareuveni M, Ben-Tal O, Kutikov I, Gill O, Mevorach D - J. Exp. Med. (2002)

Bottom Line: A significant increase (P < 0.001) in the amount of cleared apoptotic cells was seen at low ratios.In addition, iDC maturation responses to CD40L and lipopolysaccharide were significantly inhibited.We conclude that opsonization of apoptotic cells by iC3b induces tolerant iDCs that are able to migrate to lymph nodes.

View Article: PubMed Central - PubMed

Affiliation: The Laboratory for Cellular and Molecular Immunology, Rheumatology Unit, Department of Medicine, Hadassah Hospital and the Hebrew University. Sourasky Medical Center, Jerusalem 91120, Israel.

ABSTRACT
Immature dendritic cells (iDCs) do not mature after uptake of apoptotic cells and may play a role in the induction of peripheral tolerance to self antigens derived from apoptotic material. The integrins, alphavbeta3, alphavbeta5, and the scavenger receptor, CD36, have been shown to mediate uptake of apoptotic cells by iDCs. However, it is not known whether the complement system, also takes part in this process. In this study we investigated the ability of iDCs to bind to apoptotic cells opsonized by iC3b. Monocyte-derived dendritic cells were offered apoptotic Jurkat cells opsonized by autologous iC3b and labeled with 1,1'-dioctadecyl-3,3,3',3'-tetramethyl-indocarbocyanineperchlorate. A significant increase (P < 0.001) in the amount of cleared apoptotic cells was seen at low ratios. Despite increased efficiency of uptake, interaction between iC3b-opsonized apoptotic cells and iDCs down-regulated the expression of major histocompatibility complex class II, CD86, CC chemokine receptor (CCR)2, CCR5, and beta2-integrins (P < 0.001), and up-regulated expression of CCR7 (P < 0.001). In addition, iDC maturation responses to CD40L and lipopolysaccharide were significantly inhibited. We conclude that opsonization of apoptotic cells by iC3b induces tolerant iDCs that are able to migrate to lymph nodes.

Show MeSH

Related in: MedlinePlus

Apoptotic cells opsonized by iC3b, down-regulate MHC class II and CD86, and immune-paralyze the effect of CD40L or LPS, on iDCs. (A) Expression of DR-FITC and CD86-PE (bold lines) on iDCs were down-regulated upon exposure to apoptotic cells (solid lines, median fluorescence 67 to 40, and 54 to 17, respectively, P < 0.001). (B) DR-FITC and CD86-PE, expressed on iDCs (bold lines, median fluorescence 62, and 22, respectively), were up-regulated (gray lines, median fluorescence 133, and 58, respectively, P < 0.001) after exposure to CD40L. However, if iDCs were exposed to apoptotic cells, before CD40L (solid lines), up-regulation was inhibited (median fluorescence 7.4, and 7.84, respectively. P < 0.001). (C) Similarly to CD40L, DR-FITC, and CD86-PE, expressed on iDC (bold lines, median fluorescence, 57 and 55, respectively), were up-regulated (gray lines, median fluorescence 80, and 117, respectively. P < 0.001), after exposure to LPS. Again, if iDCs were exposed to apoptotic cells, before LPS (solid lines), up-regulation was inhibited (median fluorescence 60, and 71, respectively; P < 0.001).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2196062&req=5

fig4: Apoptotic cells opsonized by iC3b, down-regulate MHC class II and CD86, and immune-paralyze the effect of CD40L or LPS, on iDCs. (A) Expression of DR-FITC and CD86-PE (bold lines) on iDCs were down-regulated upon exposure to apoptotic cells (solid lines, median fluorescence 67 to 40, and 54 to 17, respectively, P < 0.001). (B) DR-FITC and CD86-PE, expressed on iDCs (bold lines, median fluorescence 62, and 22, respectively), were up-regulated (gray lines, median fluorescence 133, and 58, respectively, P < 0.001) after exposure to CD40L. However, if iDCs were exposed to apoptotic cells, before CD40L (solid lines), up-regulation was inhibited (median fluorescence 7.4, and 7.84, respectively. P < 0.001). (C) Similarly to CD40L, DR-FITC, and CD86-PE, expressed on iDC (bold lines, median fluorescence, 57 and 55, respectively), were up-regulated (gray lines, median fluorescence 80, and 117, respectively. P < 0.001), after exposure to LPS. Again, if iDCs were exposed to apoptotic cells, before LPS (solid lines), up-regulation was inhibited (median fluorescence 60, and 71, respectively; P < 0.001).

Mentions: Next we attempted to verify that the increased uptake of iC3b opsonized apoptotic cells did not induce maturation of iDCs. iDCs were stained for CD1a, DR, CD83, and CD86, before and after exposure to apoptotic cells opsonized by autologous iC3b. In Fig. 4 A, we show that iDC did not up-regulate surface DR or CD86 (as well as CD83, not shown) after uptake of apoptotic cells opsonized by iC3b. In fact, as shown in Fig. 4 A, in most experiments we observed down-regulation of DR and CD86. In addition, we measured IL-12 secretion in supernatants of iDCs exposed to opsonized apoptotic cells. No increase in baseline level was observed in up to 48 h (data not shown). To further test whether iDCs exposed to iC3b-opsonized apoptotic cells were in a state of anergy we exposed iDCs to CD40L or to anti-CD40. We observed marked inhibition of the maturation response to CD40L after exposure to iC3b-opsonized apoptotic cells (see Fig. 4 B). Remarkably, in most experiments, the expression of DR and CD86 was down-regulated to levels below levels that were seen in iDCs that were not exposed to CD40L. This immune-paralysis induced by apoptotic cells was shown also during LPS administration (Fig. 4 C). However, LPS-induced inhibition was to the basic levels of iDCs. Uptake of latex particles did not inhibit maturation after LPS and did not down-regulate the expression of CD86 and MHC class II with median fluorescence of 88 and 124, after phagocytosis, and 91 and 118 without phagocytosis, respectively.


Opsonization of apoptotic cells by autologous iC3b facilitates clearance by immature dendritic cells, down-regulates DR and CD86, and up-regulates CC chemokine receptor 7.

Verbovetski I, Bychkov H, Trahtemberg U, Shapira I, Hareuveni M, Ben-Tal O, Kutikov I, Gill O, Mevorach D - J. Exp. Med. (2002)

Apoptotic cells opsonized by iC3b, down-regulate MHC class II and CD86, and immune-paralyze the effect of CD40L or LPS, on iDCs. (A) Expression of DR-FITC and CD86-PE (bold lines) on iDCs were down-regulated upon exposure to apoptotic cells (solid lines, median fluorescence 67 to 40, and 54 to 17, respectively, P < 0.001). (B) DR-FITC and CD86-PE, expressed on iDCs (bold lines, median fluorescence 62, and 22, respectively), were up-regulated (gray lines, median fluorescence 133, and 58, respectively, P < 0.001) after exposure to CD40L. However, if iDCs were exposed to apoptotic cells, before CD40L (solid lines), up-regulation was inhibited (median fluorescence 7.4, and 7.84, respectively. P < 0.001). (C) Similarly to CD40L, DR-FITC, and CD86-PE, expressed on iDC (bold lines, median fluorescence, 57 and 55, respectively), were up-regulated (gray lines, median fluorescence 80, and 117, respectively. P < 0.001), after exposure to LPS. Again, if iDCs were exposed to apoptotic cells, before LPS (solid lines), up-regulation was inhibited (median fluorescence 60, and 71, respectively; P < 0.001).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2196062&req=5

fig4: Apoptotic cells opsonized by iC3b, down-regulate MHC class II and CD86, and immune-paralyze the effect of CD40L or LPS, on iDCs. (A) Expression of DR-FITC and CD86-PE (bold lines) on iDCs were down-regulated upon exposure to apoptotic cells (solid lines, median fluorescence 67 to 40, and 54 to 17, respectively, P < 0.001). (B) DR-FITC and CD86-PE, expressed on iDCs (bold lines, median fluorescence 62, and 22, respectively), were up-regulated (gray lines, median fluorescence 133, and 58, respectively, P < 0.001) after exposure to CD40L. However, if iDCs were exposed to apoptotic cells, before CD40L (solid lines), up-regulation was inhibited (median fluorescence 7.4, and 7.84, respectively. P < 0.001). (C) Similarly to CD40L, DR-FITC, and CD86-PE, expressed on iDC (bold lines, median fluorescence, 57 and 55, respectively), were up-regulated (gray lines, median fluorescence 80, and 117, respectively. P < 0.001), after exposure to LPS. Again, if iDCs were exposed to apoptotic cells, before LPS (solid lines), up-regulation was inhibited (median fluorescence 60, and 71, respectively; P < 0.001).
Mentions: Next we attempted to verify that the increased uptake of iC3b opsonized apoptotic cells did not induce maturation of iDCs. iDCs were stained for CD1a, DR, CD83, and CD86, before and after exposure to apoptotic cells opsonized by autologous iC3b. In Fig. 4 A, we show that iDC did not up-regulate surface DR or CD86 (as well as CD83, not shown) after uptake of apoptotic cells opsonized by iC3b. In fact, as shown in Fig. 4 A, in most experiments we observed down-regulation of DR and CD86. In addition, we measured IL-12 secretion in supernatants of iDCs exposed to opsonized apoptotic cells. No increase in baseline level was observed in up to 48 h (data not shown). To further test whether iDCs exposed to iC3b-opsonized apoptotic cells were in a state of anergy we exposed iDCs to CD40L or to anti-CD40. We observed marked inhibition of the maturation response to CD40L after exposure to iC3b-opsonized apoptotic cells (see Fig. 4 B). Remarkably, in most experiments, the expression of DR and CD86 was down-regulated to levels below levels that were seen in iDCs that were not exposed to CD40L. This immune-paralysis induced by apoptotic cells was shown also during LPS administration (Fig. 4 C). However, LPS-induced inhibition was to the basic levels of iDCs. Uptake of latex particles did not inhibit maturation after LPS and did not down-regulate the expression of CD86 and MHC class II with median fluorescence of 88 and 124, after phagocytosis, and 91 and 118 without phagocytosis, respectively.

Bottom Line: A significant increase (P < 0.001) in the amount of cleared apoptotic cells was seen at low ratios.In addition, iDC maturation responses to CD40L and lipopolysaccharide were significantly inhibited.We conclude that opsonization of apoptotic cells by iC3b induces tolerant iDCs that are able to migrate to lymph nodes.

View Article: PubMed Central - PubMed

Affiliation: The Laboratory for Cellular and Molecular Immunology, Rheumatology Unit, Department of Medicine, Hadassah Hospital and the Hebrew University. Sourasky Medical Center, Jerusalem 91120, Israel.

ABSTRACT
Immature dendritic cells (iDCs) do not mature after uptake of apoptotic cells and may play a role in the induction of peripheral tolerance to self antigens derived from apoptotic material. The integrins, alphavbeta3, alphavbeta5, and the scavenger receptor, CD36, have been shown to mediate uptake of apoptotic cells by iDCs. However, it is not known whether the complement system, also takes part in this process. In this study we investigated the ability of iDCs to bind to apoptotic cells opsonized by iC3b. Monocyte-derived dendritic cells were offered apoptotic Jurkat cells opsonized by autologous iC3b and labeled with 1,1'-dioctadecyl-3,3,3',3'-tetramethyl-indocarbocyanineperchlorate. A significant increase (P < 0.001) in the amount of cleared apoptotic cells was seen at low ratios. Despite increased efficiency of uptake, interaction between iC3b-opsonized apoptotic cells and iDCs down-regulated the expression of major histocompatibility complex class II, CD86, CC chemokine receptor (CCR)2, CCR5, and beta2-integrins (P < 0.001), and up-regulated expression of CCR7 (P < 0.001). In addition, iDC maturation responses to CD40L and lipopolysaccharide were significantly inhibited. We conclude that opsonization of apoptotic cells by iC3b induces tolerant iDCs that are able to migrate to lymph nodes.

Show MeSH
Related in: MedlinePlus