RC529-MDP is an immunological adjuvant that couples Toll-like receptors (TLR4a) and NOD-like receptors (NOD2a) to enhance the innate immune response through the TLR4 and NOD2 signaling pathways. In mouse models, RC529-MDP induces high levels of the cytokine interleukin-related factor (IL-6), highlighting its immunostimulatory activity. Additionally, when injected into mice models with ovalbumin (OVA), RC529-MDP elevates OVA-specific antibody responses, T cell responses, and the proportion of memory T cells.

RC529-MDP (9.3 μM, 20 h) exhibits activity that is dependent on the TLR4 and NOD2 signaling pathways. In Raw264.7 cells, the conjugate form of RC529-MDP increases the proportion of CD80 and CD86 cells by 1.7 times compared to the mixture of RC529 + MDP, effectively promoting the maturation of antigen-presenting cells (APC).

In laboratory mice, the RC529-MDP conjugate demonstrated a robust enhancement of IL-6 levels, increasing them by 6.8-fold and inducing a powerful synergistic effect. When administered intraperitoneally (i.p.) at a dose of 22.53 μg, RC529-MDP significantly boosted humoral immunity and elevated levels of IgG subclasses (IgG1, IgG2a, IgG2b). Similarly, when RC529-MDP (22.53 μg, s.c.) was co-injected with OVA in mice, there was a rapid activation of adaptive humoral immunity accompanied by an increase in cytokine-secreting T cells, leading to a strong cell-mediated immune response. Moreover, RC529-MDP (22.53 μg) increased the proportion of central memory T cells (Tcm), generating a memory response.