Destructive arthritis in the absence of both FcγRI and FcγRIII

P Boross, PL van Lent, J Martin-Ramirez… - The Journal of …, 2008 - journals.aai.org
P Boross, PL van Lent, J Martin-Ramirez, J van der Kaa, MHCM Mulder, JWC Claassens…
The Journal of Immunology, 2008journals.aai.org
Abstract Fc receptors for IgG (FcγR) have been implicated in the development of arthritis.
However, the precise contribution of the individual FcγR to joint pathology is unclear. In this
study, the role of the different FcγR was assessed both in an active and in a passive mouse
model of arthritis by analyzing disease development in double and triple knockout (KO)
offspring from crosses of FcγRI KO, FcγRIII KO, FcγRI/III double KO, or FcR γ-chain KO with
the FcγRII KO on C57BL6 background, which is susceptible for collagen-induced arthritis …
Abstract
Fc receptors for IgG (FcγR) have been implicated in the development of arthritis. However, the precise contribution of the individual FcγR to joint pathology is unclear. In this study, the role of the different FcγR was assessed both in an active and in a passive mouse model of arthritis by analyzing disease development in double and triple knockout (KO) offspring from crosses of FcγRI KO, FcγRIII KO, FcγRI/III double KO, or FcR γ-chain KO with the FcγRII KO on C57BL6 background, which is susceptible for collagen-induced arthritis (CIA). In the active CIA model, onset was significantly delayed in the absence of FcγRIII, whereas incidence and maximum severity were significantly decreased in FcγRI/II/III triple KO but not in FcγRII/III double KO and FcγRI/II double KO mice as compared with FcγRII KO animals. Remarkably, fully destructive CIA developed in FcγRI/II/III triple KO mice. In contrast, FcR γ/FcγRII double KO mice were resistant to CIA. These findings were confirmed with the passive KRN serum-induced arthritis model. These results indicate that all activating FcγR play a role in the development of arthritis, mainly in the downstream effector phase. FcγRIII is critically required for early arthritis onset, and FcγRI can substantially contribute to arthritis pathology. Importantly, FcγRI and FcγRIII were together dispensable for the development of destructive arthritis but the FcR γ-chain was not, suggesting a role for another FcR γ-chain associated receptor, most likely FcγRIV. In addition, FcγRII plays a negative regulatory role in both the central and effector phase of arthritis.
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