FIGURE 1.

Immune responses induced by virus‐like particles (VLPs). 1: VLP interacts with pattern recognition receptors (PRRs) presence on the dendritic cell (DC), such as the toll‐like receptor (TLR). DC then engulf the VLP through phagocytosis or micropinocytosis. 2: This leads to the maturation of DC, which then secretes pro‐inflammatory cytokines such as TNF‐α and IL‐1β to recruit more antigen presenting cells (APCs), including DCs and macrophages. 3: VLP taken up by the DC are then enzymatically digested into short peptides, which binds to major histocompatibility complex class I (MHC I) and class II (MHC II) and are transported onto surface of the DC. 4: Short peptide displayed on MHC II, together with CD40 and CD80/86 then interact with T cell receptor (TCR), CD40L, and CD28 presence on naïve helper T cell (Th), respectively. This promotes the proliferation and differentiation of Th cells into type 1 (Th1) and type 2 (Th2) Th cells. 5: Similarly, peptides displayed on MHC I of the DC, along with CD40 and CD80/86 interact with TCR, CD40L, and CD28 presence on the naïve cytotoxic T lymphocyte (CTL). Aided by Th1, naïve CTL proliferates and differentiates into effector and memory CTLs, providing immediate and long‐lasting cellular immunity, respectively. 7: Naïve B cell on other hand interacts with intact VLP carried over by blood stream or DC via B cell receptor (BCR). Aided by Th2, the B cell differentiates into plasma B cells which actively secrete antibodies, and memory B cells which provides long‐lasting humoral immunity against the antigen presence on the VLP