The particle size of the liposomes samples taken at each time point was recorded. 2.3. promoted the OVA-specific IgG and IgG isotypes levels, enhanced the splenocyte proliferation, and induced the NK cell and CTL cytotoxicity. Besides, the anti-DEC-205-EUPS-OVA-LPSM enhanced the maturation of DCs. These findings suggest that the DEC-205 receptor antibody-conjugated EUPS nanoliposome can act as an efficient antigen delivery system to enhance the cellular and humoral immune response by promoting DC maturation. This indicates that this anti-DEC-205-EUPS-OVA-LPSM has significant potential as an immune-enhancing agent and antigen delivery system. polysaccharide, nanoliposome, dendritic cells, immune response 1.?Introduction Animal husbandry incurs a heavy loss worldwide due to infectious diseases, notably Poloxin viral infections. Vaccination remains the most effective means to combat infectious diseases. Vaccination regimes are strictly followed in the farms; even then, in most of the cases, animals Poloxin do not produce the desired immune response due to which most of the infections could not be completely controlled (Monath, 2013; Afolabi et?al., 2019; Fan et?al., 2020; Ma et?al., 2020). Application of appropriate immune enhancers can improve the vaccine efficacy and assist the vaccines in producing better immune responses (Bookstaver et?al., 2018; Ratnapriya et?al., 2019). The application of immune enhancers has become one of the crucial tools in improving vaccine-induced immune responses. Various researchers have exhibited that traditional Chinese medicine and its effective components can significantly improve the vaccine-induced cellular and humoral immune responses. A variety of traditional Chinese medicine and its core components as immune enhancers of vaccines are currently being used in animals and humans (Rodrigues Barbosa et?al., 2020). Over the past few years, various studies have exhibited the adjuvant effect of a myriad of traditional Chinese medicinal herb polysaccharides around the antigen-specific humoral and cellular immune responses in pathogenic infections (Feng et?al., 2013, 2015; Sun et?al., 2018). Herb polysaccharides have several advantages over other adjuvants, such as better safety and tolerability, and easy to manufacture formulation. Thus, the herb polysaccharides have the potential of being used as adjuvants for Mbp the vaccines against infectious brokers and malignancies. The Oliv. (EU) is Chinese traditional medicine with multiple pharmacological activities. In our previous Poloxin study, we have found that the polysaccharides extracted from Oliv. (EUPS) regulated DCs maturation and served as an immune-enhancer; besides, it activated the DCs, Poloxin and promoted the antigen-specific humoral and cellular response (Feng et?al., 2016). Dendritic cells (DCs) as an antigen-presenting cell (APC), can integrate innate and adaptive immune responses. The bone marrow hematopoietic progenitors derived immature DCs circulate in the blood and can be spotted in tissues as sentinel cells, and recognize antigen or take up the pathogen from the extracellular environment by employing the receptor-mediated endocytosis, pinocytosis, and micropinocytosis (Sadeghzade et?al., 2020; Shortman, 2020). It can efficiently process distinct antigens and load them to major histocompatibility complexes (MHC I and MHC II). DCs eventually migrate to the secondary lymphoid organ (lymph nodes). They transform to mature DCs and present the processed antigens to the Th cells, thus initiating Poloxin the adaptive immune response after being recognized by CD4+ or CD8+ T cells (Patente et?al., 2019). DCs initiate cellular signaling. However, this signal is usually insufficient to induce T cell activation and necessitates a secondary signal (Giovanelli et?al., 2019; Zhu et?al., 2019). The costimulatory signaling molecules such as CD40, CD80, and CD86 are expressed around the DCs surface, which generates the secondary signal. These receptors interact with CD40L and CD28 around the T cell surface, activate T cells, and elicits antigen-specific immune responses. This indicates that the successful delivery of antigens by DCs is usually a crucial factor for effective immunization against infectious diseases, malignancy, and autoimmune diseases (Qian & Cao, 2018). Therefore, multiple studies are investigating the means to specifically target the antigens to the immature DCs by using.