Pam3CSK4 is a novel and potent TLR1/2 (toll-like receptor 1/2) agonist with an EC50 of 0.47 ng/mL for human TLR1/2. Pam3CSK4 is able to attenuate inflammatory responses caused by systemic infection of methicillin-resistant Staphylococcus aureus in mice. Combination of C and Pam3CSK4 enhances activation of B cells in vitro and boosts antibody responses to protein vaccines in vivo.