Identification and immunological evaluation of novel TLR2 agonists through structure optimization of Pam3CSK4

•A novel series of Pam3CSK4 derivatives were designed, prepared, and evaluated for their immune-stimulatory activities based on the study of crystal structure of hTLR2-hTLR1-Pam3CSK4 complex.•Compound 35c was identified as a murine-specific TLR2 agonist, while 35f was a human-specific TLR2 agonist.•Compound 35d (human and murine TLR2 agonist) showed comparable TLR2 agonistic activity to Pam3CSK4.•Compounds 35a and 35d were TLR2/1 agonists, while 35f was a TLR2/6 agonist.