Immune Netw.  2008 Mar;8(1):21-28. 10.4110/in.2008.8.1.21.

A Co-inhibitory Molecule, B7-H4, Synergistically Potentiates Oral Tolerance by Inducing CD4+CD25+FoxP3+ T Cells

• Wen L
• Yang S
• Choi J
• Kim Y
• Kwon E
• Lee H
• Jeoung H
• Hwang D
• Hwang D
• Choi I

• KMID: 2054255
• DOI: http://doi.org/10.4110/in.2008.8.1.21

Abstract

BACKGROUND
A co-inhibitory molecule, B7-H4, is believed to negatively regulate T cell immunity by suppressing T cell proliferation and inhibiting cytokine production. However, the mechanism behind B7-H4-mediated tolerance remains unclear.
METHODS
Balb/c (H-2(d)) mice were fed with dendritic cell line, DC2.4 (H-2(b)) every day for 10 days. Meantime, mice were hydrodynamically injected with recombinant plasmid expressing B7-H4 fusion protein (B7-H4.hFc) or hFc via tail vein. One day after last feeding, mice were immunized with allogeneic B6 spleen cells. 14 days following immunization, mice were challenged with B6 spleen cells to ear back and the ear swelling was determined the next day. Subsequently, a mixed lymphocyte reaction (MLR) was also performed and cytokines profiles from the reaction were examined by sandwich ELISA. Frequency of immunosuppressive cell population was assayed with flow cytometry and mRNA for FoxP3 was determined by RT-PCR. RESULTS: Tolerant mice given plasmid expressing B7-H4.hFc showed a significant reduction in ear swelling compared to control mice. In addition, T cells from mice given B7-H4.hFc plasmid revealed a significant hyporesponsiveness of T cells against allogeneic spleen cells and showed a significant decrease in Th1 and Th2 cytokines such as IFN-gamma, IL-5, and TNF-alpha. Interestingly, flow cytometric analysis showed that the frequency of CD4+CD25+FoxP3+ Tregs in spleen was increased in tolerant mice given recombinant B7-H4.hFc plasmid compared to control group. CONCLUSION: Our results demonstrate that B7-H4 synergistically potentiates oral tolerance induced by allogeneic cells by increasing the frequency of FoxP3+ CD4+CD25+ Treg and reducing Th1 and Th2 cytokine production.

Keyword

B7-H4; oral tolerance; delayed type hypersensitivity

MeSH Terms

Animals
Cell Proliferation
Cytokines
Dendritic Cells
Ear
Enzyme-Linked Immunosorbent Assay
Flow Cytometry
Immunization
Interleukin-5
Lymphocyte Culture Test, Mixed
Mice
Plasmids
RNA, Messenger
Spleen
T-Lymphocytes
Tumor Necrosis Factor-alpha
Veins
Cytokines
Interleukin-5
RNA, Messenger
Tumor Necrosis Factor-alpha