Transmembrane activator and
calcium modulator and
cyclophilin ligand interactor-
immunoglobulin (
TACI-Ig) is a human fusion
protein that binds and neutralizes both
B lymphocyte stimulator (BLyS), a
cytokine shown to be a key regulator of B cell maturation, proliferation and survival, and a proliferation-inducing
ligand (APRIL). Rat
adjuvant arthritis (AA) is an experimental animal model of
rheumatoid arthritis (RA), which is mainly dependent on T cells and neutrophil-mediated
cytokine production. The purpose of the present study was to investigate the effects of
TACI-Ig on rat AA. Rat AA was induced by
intradermal injection of 0·1 ml complete
Freund's adjuvant (CFA).
TACI-Ig (0·7, 2·1 and 6·3 mg/kg), recombinant human tumour
necrosis factor-α receptor (rhTNFR) : Fc (2·8 mg/kg) and
IgG-Fc (6·3 mg/kg) were administered subcutaneously every other day from days 16 to 34 after immunization.
Arthritis was evaluated by
arthritis global assessment and swollen joint count (SJC). The ankle joint and spleen were harvested for histopathological examination. Spleen index and thymus index were calculated. The levels of BLyS,
interleukin (IL)-17,
interferon (IFN)-γ,
IgG1,
IgG2a and
IgM in AA rat spleen were measured by
enzyme-linked
immunosorbent assay. Administration of
TACI-Ig significantly reduced the
arthritis global assessment and SJC, decreased spleen index and ameliorated histopathological manifestations of rat AA. Suppressing the levels of BLyS,
IL-17, IFN-γ and Ig in AA rat spleen were observed after administration of
TACI-Ig. These results showed that
TACI-Ig significantly inhibited the degree of rat AA, and the inhibitory effects might be associated with its ability to reduce BLyS, proinflammatory
cytokines and Ig levels in spleen.