PurposeThe aim of this study is to explore the role of social tie content in the interpersonal knowledge transfer process and to test the effects of different social ties, i.e. distinguishing instrumental tie and expressive tie, on knowledge transfer, using cognition‐ and affect‐based trust as the mediators.Design/methodology/approachA theoretical model was tested through a survey carried out on 152 MBA students of a university in east China, and structural equation modelling (SEM) was employed for data analysis.FindingsThis research proved that both instrumental and expressive ties will facilitate trust and knowledge transfer. Cognition‐based trust is not essential when low‐tacit, general knowledge is transferred, and the effect of the expressive tie becomes negative when trust is controlled. When transferring general knowledge the instrumental tie is more efficient. However, contrary to the hypothesis, it is found that the effect of the expressive tie is not significantly larger than that of the instrumental tie during the tacit knowledge transfer process.Research limitations/implicationsBesides tacitness, future research may consider involving more dimensions of knowledge into the theoretical model. Longitudinal and cross‐national studies are also needed.Practical implicationsThe paper suggests that managers can enhance knowledge transfer among co‐workers by enhancing their instrumental and expressive ties. However, overuse of the expressive tie is risky. The importance of trust construction in organizations is also underscored.Originality/valueThe study reminds scholars to pay attention to the role of tie content in knowledge transfer. The findings also help managers to know how to increase knowledge transfer through promoting intra‐organizational networking.

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The tumor‐associated antigen mucin 1 (MUC1) has been pursued as an attractive target for cancer immunotherapy, but the poor immunogenicity of the endogenous antigen hinders the development of vaccines capable of inducing effective anti‐MUC1 immunodominant responses. Herein, we prepared synthetic anti‐MUC1 vaccines in which the hydrophilic MUC1 antigen was N‐terminally conjugated to one or two palmitoyl lipid chains (to form amphiphilic Pam‐MUC1 or Pam2‐MUC1). These amphiphilic lipid‐tailed MUC1 antigens were self‐assembled into liposomes containing the NKT cell agonist αGalCer as an adjuvant. The lipid‐conjugated antigens reshaped the physical and morphological properties of liposomal vaccines. Promising results showed that the anti‐MUC1 IgG antibody titers induced by the Pam2‐MUC1 vaccine were more than 30‐ and 190‐fold higher than those induced by the Pam‐MUC1 vaccine and the MUC1 vaccine without lipid tails, respectively. Similarly, vaccines with the TLR1/2 agonist Pam3CSK4 as an adjuvant also induced conjugated lipid‐dependent immunological responses. Moreover, vaccines with the αGalCer adjuvant induced significantly higher titers of IgG antibodies than vaccines with the Pam3CSK4 adjuvant. Therefore, the non‐covalent assembly of the amphiphilic lipo‐MUC1 antigen and the NKT cell agonist αGalCer as a glycolipid adjuvant represent a synthetically simple but immunologically effective approach for the development of anti‐MUC1 cancer vaccines.

Safe and effective vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its variants are the best approach to successfully combat the COVID-19 pandemic. The receptor-binding domain (RBD) of the viral spike protein is a major target to develop candidate vaccines. α-Galactosylceramide (αGalCer), a potent invariant natural killer T cell (iNKT) agonist, was site-specifically conjugated to the N -terminus of the RBD to form an adjuvant–protein conjugate, which was anchored on the liposome surface. This is the first time that an iNKT cell agonist was conjugated to the protein antigen. Compared to the unconjugated RBD/αGalCer mixture, the αGalCer-RBD conjugate induced significantly stronger humoral and cellular responses. The conjugate vaccine also showed effective cross-neutralization to all variants of concern (B.1.1.7/alpha, B.1.351/beta, P.1/gamma, B.1.617.2/delta, and B.1.1.529/omicron). These results suggest that the self-adjuvanting αGalCer-RBD has great potential to be an effective COVID-19 vaccine candidate, and this strategy might be useful for designing various subunit vaccines.

Many cancer vaccines are not successful in clinical trials, mainly due to the challenges associated with breaking immune tolerance. Herein, we report a new strategy using an adjuvant-protein-antigen (three-in-one protein conjugates with built-in adjuvant) as an anticancer vaccine, in which both the adjuvant (small-molecule TLR7 agonist) and tumor-associated antigen (mucin 1, MUC1) are covalently conjugated to the same carrier protein (BSA). It is shown that the protein conjugates with built-in adjuvant can increase adjuvant's stimulation, prevent adjuvant's systemic toxicities, facilitate the codelivery of adjuvants and antigens, and enhance humoral and cellular immune responses. The IgG antibody titers elicited by the self-adjuvanting three-in-one protein conjugates were significantly higher than those elicited by the vaccine mixed with TLR7 agonist (more than 15-fold) or other traditional adjuvants. Importantly, the potent immune responses against cancer cells suggest that this new vaccine construct is an effective strategy for the personalized antitumor immunotherapy.

The coronavirus 2019 (COVID-19) pandemic is causing serious impact in the world, safe and effective vaccines and medicines are the best method to combat the disease. The receptor-binding domain (RBD)...

Adjuvants are important components in vaccines to increase the immunogenicity of proteins and induce optimal immunity. In this study, we designed a novel ternary adjuvant system Alum+c-GAMP+poly(I:C) with STING agonist...

The tumor-associated antigen mucin 1 (MUC1) is an attractive target of antitumor vaccine, but its weak immunogenicity is a big challenge for the development of vaccine. In order to enhance immune responses against MUC1, herein, we conjugated small molecular toll-like receptor 7 agonist (TLR7a) to carrier protein BSA via MUC1 glycopeptide to form a three-component conjugate (BSA-MUC1-TLR7a). Furthermore, we combined the three-component conjugate with Alum adjuvant to explore their synergistic effects. The immunological studies indicated that Alum adjuvant and built-in TLR7a synergistically enhanced anti-MUC1 antibody responses and showed Th1-biased immune responses. Meanwhile, antibodies elicited by the vaccine candidate effectively recognized tumor cells and induced complement-dependent cytotoxicity. In addition, Alum adjuvant and built-in TLR7a synergistically enhanced MUC1 glycopeptide-specific memory CD8+ T-cell immune responses. More importantly, the vaccine with the binary adjuvant can significantly inhibit tumor growth and prolong the survival time of mice in the tumor challenge experiment. This novel vaccine construct provides an effective strategy to develop antitumor vaccines.