Adjuvant and immunomodulatory potential of Natural Killer T (NKT) activation by NKTT320

Invariant natural killer T-lymphocytes (iNKT) are a unique subset of immunomodulatory innate T-cells with an invariant TCRa chain recognizing glycolipids presented on the MHC class-I-like CD1d molecule. Activated iNKT rapidly secrete pro-and anti-inflammatory cytokines, potentiate innate and adaptive immunity, and modulate inflammation. While iNKT activation by glycolipid agonists are being explored as an adjuvant, their use depends on CD1d-restricted antigen presentation. Here, we report the effects of iNKT activation by a novel humanized monoclonal antibody, NKTT320, that binds to the invariant region of the iNKT TCR. A single dose of NKTT320 led to rapid iNKT activation, increased polyfunctionality, and elevation of multiple pro-inflammatory and chemotactic plasma analytes within 24 hours in cynomolgus macaques. Flow cytometry and RNA-Seq confirmed downstream effects of NKTT320 on multiple immune cell subsets. Inflammatory response, JAK/STAT and PI3K/AKT pathway genes were enriched along with upregulation of the inflammation-modulating genes CMKLR1, ARG2 and NLRP12. Finally, NKTT320 induced iNKT trafficking to adipose tissue and did not cause iNKT anergy. Our data indicate that NKTT320 has a sustained effect on in vivo iNKT activation, potentiation of innate and adaptive immunity, and resolution of inflammation, properties that support its future application as an immunotherapeutic and vaccine adjuvant.