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Immunomodulatory Effects of Hypocrellin A on MHC-restricted Antigen Processing.

Park S, Im SA, Kim KH, Lee CK - Immune Netw (2011)

Bottom Line: Here we report that hypocrellin A exerts immunomodulatory effects on MHC-restricted presentation of antigen.However, hypocrellin A did not inhibit the expression of class I and class II MHC molecules on dendritic cells (DCs), the phagocytic activity of DCs, or the H-2K(b)-restricted presentation of a synthetic peptide, SIINFEKL.These results show that hypocrellin A differentially modulates the MHC-restricted antigen presentation pathways.

View Article: PubMed Central - PubMed

Affiliation: College of Pharmacy, Chungbuk National University, Cheongju 361-763, Korea.

ABSTRACT
Hypocrellin A has gained much attention in recent years due to its light-induced antitumor, antifungal and antiviral activities. Here we report that hypocrellin A exerts immunomodulatory effects on MHC-restricted presentation of antigen. Hypocrellin A inhibited class II-MHC restricted presentation of exogenous antigen, but not class I MHC-restricted presentation of exogenous antigen, in dendritic cells. Hypocrellin A also inhibited the cytosolic pathway of endogenous antigen presentation. However, hypocrellin A did not inhibit the expression of class I and class II MHC molecules on dendritic cells (DCs), the phagocytic activity of DCs, or the H-2K(b)-restricted presentation of a synthetic peptide, SIINFEKL. These results show that hypocrellin A differentially modulates the MHC-restricted antigen presentation pathways.

No MeSH data available.


Effects of hypocrellin A on the MHC-restricted presentation of exogenous OVA. (A) DC2.4 cells were incubated with the indicated amounts of hypocrellin A for 2 h, and then biodegradable microspheres containing OVA (50µg/ml as OVA) were added to the cultures for 2 h. The cells were then fixed with paraformaldehyde, and the amounts of OVA peptides presented on MHC class I molecules were assessed by a LacZ T cell activation assay using OVA-specific CD8 T cell hybridoma B3Z cells. (B) BM-DCs generated from bone marrow cells of BALB/c mice were incubated with the indicated amounts of hypocrellin A for 2 h, and then biodegradable microspheres containing OVA (50µg/ml as OVA) were added to the cultures for 2 h. The cells were then washed, fixed with paraformaldehyde, and the amounts of OVA peptides presented on MHC class II molecules were assessed using OVA-specific CD4 T cell hybridoma DOBW cells.
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Figure 1: Effects of hypocrellin A on the MHC-restricted presentation of exogenous OVA. (A) DC2.4 cells were incubated with the indicated amounts of hypocrellin A for 2 h, and then biodegradable microspheres containing OVA (50µg/ml as OVA) were added to the cultures for 2 h. The cells were then fixed with paraformaldehyde, and the amounts of OVA peptides presented on MHC class I molecules were assessed by a LacZ T cell activation assay using OVA-specific CD8 T cell hybridoma B3Z cells. (B) BM-DCs generated from bone marrow cells of BALB/c mice were incubated with the indicated amounts of hypocrellin A for 2 h, and then biodegradable microspheres containing OVA (50µg/ml as OVA) were added to the cultures for 2 h. The cells were then washed, fixed with paraformaldehyde, and the amounts of OVA peptides presented on MHC class II molecules were assessed using OVA-specific CD4 T cell hybridoma DOBW cells.

Mentions: The present study reports that hypocrellin A differentially modulates MHC-restricted antigen presentation pathways. To examine the effects of hypocrellin A on the MHC-restricted antigen presentation, DC2.4 cells, a dendritic cell (DC) cell line, were incubated with hypocrellin A for 2 h, and then biodegradable microspheres containing ovalbumin (OVA, 50µg/ml as OVA) were added to the cultures for 2 h. The process used to fabricate OVA-containing biodegradable microspheres was previously described in detail (12). The cells were then fixed with paraformaldehyde and washed thoroughly with PBS. The amounts of OVA peptides presented via class I MHC molecules were assessed in B3Z cells (H-2b), which express β-galactosidase upon recognition of H-2Kb-OVA peptide complexes, as described previously (13). The effects of hypocrellin A on the class II MHC-restricted presentation of exogenous OVA were examined in bone marrow-derived DCs (BM-DCs), which were generated from BM cells of BALB/c mice (H-2d) by culturing 6 days in the presence of 200 units/ml of GM-CSF. After culturing BM-DCs with biodegradable microspheres containing OVA (50µg/ml as OVA) for 2 h, the BM-DCs were fixed with paraformaldehyde, washed, and then co-cultured with DOBW cells, which express IL-2 upon recognition of I-Ad-OVA peptide complexes, as described previously (14). As shown in Fig. 1A, hypocrellin A did not inhibit class I MHC-restricted presentation of exogenous OVA. However, hypocrellin A dose-dependently inhibited class II MHC-restricted presentation of exogenous OVA (Fig. 1B). The IC50 was approximately 80 nM. These results show that hypocrellin A preferentially inhibits the class II MHC-restricted presentation pathway of exogenous antigen.


Immunomodulatory Effects of Hypocrellin A on MHC-restricted Antigen Processing.

Park S, Im SA, Kim KH, Lee CK - Immune Netw (2011)

Effects of hypocrellin A on the MHC-restricted presentation of exogenous OVA. (A) DC2.4 cells were incubated with the indicated amounts of hypocrellin A for 2 h, and then biodegradable microspheres containing OVA (50µg/ml as OVA) were added to the cultures for 2 h. The cells were then fixed with paraformaldehyde, and the amounts of OVA peptides presented on MHC class I molecules were assessed by a LacZ T cell activation assay using OVA-specific CD8 T cell hybridoma B3Z cells. (B) BM-DCs generated from bone marrow cells of BALB/c mice were incubated with the indicated amounts of hypocrellin A for 2 h, and then biodegradable microspheres containing OVA (50µg/ml as OVA) were added to the cultures for 2 h. The cells were then washed, fixed with paraformaldehyde, and the amounts of OVA peptides presented on MHC class II molecules were assessed using OVA-specific CD4 T cell hybridoma DOBW cells.
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Related In: Results  -  Collection

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Figure 1: Effects of hypocrellin A on the MHC-restricted presentation of exogenous OVA. (A) DC2.4 cells were incubated with the indicated amounts of hypocrellin A for 2 h, and then biodegradable microspheres containing OVA (50µg/ml as OVA) were added to the cultures for 2 h. The cells were then fixed with paraformaldehyde, and the amounts of OVA peptides presented on MHC class I molecules were assessed by a LacZ T cell activation assay using OVA-specific CD8 T cell hybridoma B3Z cells. (B) BM-DCs generated from bone marrow cells of BALB/c mice were incubated with the indicated amounts of hypocrellin A for 2 h, and then biodegradable microspheres containing OVA (50µg/ml as OVA) were added to the cultures for 2 h. The cells were then washed, fixed with paraformaldehyde, and the amounts of OVA peptides presented on MHC class II molecules were assessed using OVA-specific CD4 T cell hybridoma DOBW cells.
Mentions: The present study reports that hypocrellin A differentially modulates MHC-restricted antigen presentation pathways. To examine the effects of hypocrellin A on the MHC-restricted antigen presentation, DC2.4 cells, a dendritic cell (DC) cell line, were incubated with hypocrellin A for 2 h, and then biodegradable microspheres containing ovalbumin (OVA, 50µg/ml as OVA) were added to the cultures for 2 h. The process used to fabricate OVA-containing biodegradable microspheres was previously described in detail (12). The cells were then fixed with paraformaldehyde and washed thoroughly with PBS. The amounts of OVA peptides presented via class I MHC molecules were assessed in B3Z cells (H-2b), which express β-galactosidase upon recognition of H-2Kb-OVA peptide complexes, as described previously (13). The effects of hypocrellin A on the class II MHC-restricted presentation of exogenous OVA were examined in bone marrow-derived DCs (BM-DCs), which were generated from BM cells of BALB/c mice (H-2d) by culturing 6 days in the presence of 200 units/ml of GM-CSF. After culturing BM-DCs with biodegradable microspheres containing OVA (50µg/ml as OVA) for 2 h, the BM-DCs were fixed with paraformaldehyde, washed, and then co-cultured with DOBW cells, which express IL-2 upon recognition of I-Ad-OVA peptide complexes, as described previously (14). As shown in Fig. 1A, hypocrellin A did not inhibit class I MHC-restricted presentation of exogenous OVA. However, hypocrellin A dose-dependently inhibited class II MHC-restricted presentation of exogenous OVA (Fig. 1B). The IC50 was approximately 80 nM. These results show that hypocrellin A preferentially inhibits the class II MHC-restricted presentation pathway of exogenous antigen.

Bottom Line: Here we report that hypocrellin A exerts immunomodulatory effects on MHC-restricted presentation of antigen.However, hypocrellin A did not inhibit the expression of class I and class II MHC molecules on dendritic cells (DCs), the phagocytic activity of DCs, or the H-2K(b)-restricted presentation of a synthetic peptide, SIINFEKL.These results show that hypocrellin A differentially modulates the MHC-restricted antigen presentation pathways.

View Article: PubMed Central - PubMed

Affiliation: College of Pharmacy, Chungbuk National University, Cheongju 361-763, Korea.

ABSTRACT
Hypocrellin A has gained much attention in recent years due to its light-induced antitumor, antifungal and antiviral activities. Here we report that hypocrellin A exerts immunomodulatory effects on MHC-restricted presentation of antigen. Hypocrellin A inhibited class II-MHC restricted presentation of exogenous antigen, but not class I MHC-restricted presentation of exogenous antigen, in dendritic cells. Hypocrellin A also inhibited the cytosolic pathway of endogenous antigen presentation. However, hypocrellin A did not inhibit the expression of class I and class II MHC molecules on dendritic cells (DCs), the phagocytic activity of DCs, or the H-2K(b)-restricted presentation of a synthetic peptide, SIINFEKL. These results show that hypocrellin A differentially modulates the MHC-restricted antigen presentation pathways.

No MeSH data available.