J Rheum Dis.  2017 Oct;24(5):271-278. 10.4078/jrd.2017.24.5.271.

Interleukin-17 Enhances Germinal Center Formation and Immunoglobulin G1 Production in Mice

• Lee J
• Lee SY
• Kang CM
• Jhun JY
• Kim JH
• Cho ML
• Park SH
• Kim HY
• Kwok SK

• KMID: 2394342
• DOI: http://doi.org/10.4078/jrd.2017.24.5.271

Abstract

OBJECTIVE
Interleukin (IL)-17 is a pro-inflammatory cytokine that has pleiotropic effects on multiple target cells and thereby contributes to the development of immune-mediated inflammatory disorders. However, the role of IL-17 in the humoral immune response has not been clearly elucidated.
METHODS
Mice deficient in IL-17A (IL-17A knockout [KO] mice) and wild type (WT) C57BL/6 mice were compared. Distinct B cell (mature/precursor and marginal zone/follicular) and plasma cell populations were compared using fluorescence-activated cell sorting (FACS) and confocal immunostaining. Immunoglobulin production was assessed by enzyme-linked immunosorbent assay.
RESULTS
There was no difference in B cell and plasma cell populations between IL-17A KO and WT mice. However, after T cell-dependent antigen challenge, IL-17A KO mice produced lower levels of immunoglobulin (Ig)G1 than wild-type animals. IL-17A KO mice also showed reduced germinal center (GC) formation and lower expression of activation-induced cytidine deaminase, the essential enzyme for class switch recombination (CSR). IL-17 had no effect on the proliferation or survival of naïve B cells in in vitro functional studies. However, IL-17 treatment promoted naïve B cell differentiation into plasma cells in synergy with IL-4, although IL-17 alone had no effect.
CONCLUSION
Our findings suggest that IL-17 contributes to the humoral immune response by enhancing GC formation, CSR to IgG1, and plasma cell differentiation in synergy with IL-4.

Keyword

Interleukin-17; B cell; Germinal center

MeSH Terms

Animals
B-Lymphocytes
Cell Differentiation
Cytidine Deaminase
Enzyme-Linked Immunosorbent Assay
Flow Cytometry
Germinal Center*
Immunity, Humoral
Immunoglobulin G
Immunoglobulins*
In Vitro Techniques
Interleukin-17*
Interleukin-4
Interleukins
Mice*
Plasma Cells
Recombination, Genetic
Cytidine Deaminase
Immunoglobulin G
Immunoglobulins
Interleukin-17
Interleukin-4
Interleukins