Active immunisation targeting nerve growth factor attenuates chronic pain behaviour in murine osteoarthritis
von Loga IS., El-Turabi A., Jostins L., Miotla-Zarebska J., Mackay-Alderson J., Zeltins A., Parisi I., Bachmann MF., Vincent TL.
<jats:sec><jats:title>Objectives</jats:title><jats:p>Nerve growth factor (NGF) has emerged as a key driver of pain in osteoarthritis (OA) and antibodies to NGF are potent analgesics in human disease. Here, we validate a novel vaccine strategy to generate anti-NGF antibodies for reversal of pain behaviour in a surgical model of OA.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>Virus-like particles were derived from the cucumber mosaic virus (CuMV) and coupled to expressed recombinant NGF to create the vaccine. 10-week-old male mice underwent partial meniscectomy to induce OA or sham-surgery. Spontaneous pain behaviour was measured by Linton incapacitance and OA severity was quantified using OARSI histological scoring. Mice (experimental and a sentinel cohort) were inoculated with CuMVtt<jats:sup>NGF</jats:sup> (Vax) or CuMVtt<jats:sup>ctrl</jats:sup> (Mock) either before surgery or once pain was established. Efficacy of anti-NGF from the plasma of sentinel vaccinated mice was measured in vitro using a neurite outgrowth assay in PC12 cells.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Anti-NGF titres were readily detectable in the vaccinated but not mock vaccinated mice. Regular boosting with fresh vaccine was required to maintain anti-NGF titres as measured in the sentinel cohort. Both prophylactic and therapeutic vaccination demonstrated a reversal of pain behaviour by incapacitance testing, and a meta-analysis of the two studies showing analgesia at peak anti-NGF titres was highly statistically significant. Serum anti-NGF was able to inhibit neurite outgrowth equivalent to around 150 ug/mL of recombinant monoclonal antibody.</jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p>This study demonstrates therapeutic efficacy of a novel NGF vaccine strategy that reversibly alleviates spontaneous pain behaviour in surgically induced murine OA.</jats:p></jats:sec>