QS-21 is a purified soapbark tree (Quillaja saponaria) extract that enhances the ability of the immune system to respond to vaccine antigens. QS-21 is a promising adjuvant candidate for use in humans due to the ease of purification, its improved safety profile, and its ability to enhance cellular and humoral immunogenicity. The mechanism of action of QS-21 was speculated to be similar to QA, forming complexes with cholesterol that intercalate into the cell membrane lipids. This intercalation creates pores in the membrane to accelerate the uptake of a co-delivered antigen by the antigen presenting cells. Multiple clinical trials using QS-21 as an adjuvant, demonstrated satisfactory safety profiles and enhanced immunogenicity in immunocompromised volunteers

Dalbavancin is a mixture of five closely related active homologs (A0, A1, B0, B1, and B2); the component B0 is the major component of dalbavancin. The predominant component of dalbavancin is Factor B0, which accounts for >75% of the whole complex. Dalbavancin is a second-generation lipoglycopeptide antibiotic that was designed to improve on the natural glycopeptides currently available, such as vancomycin and teicoplanin. Modifications from these older glycoprotein classes allowed a similar mechanism of action with increased activity and once weekly dosing. Its use is indicated for the treatment of acute bacterial skin and skin structure infections (ABSSSI) caused by the following gram-positive microorganisms: Staphylococcus aureus (including methicillin-susceptible and methicillin-resistant strains), S. pyogenes, S. agalactiae, and S. anginosus group (including S. anginosus, S. intermedius, and S. constellatus). Under the brand name DALVANCE Dalbavancin is indicated for acute bacterial skin and skin structure infections (ABSSSI) caused by designated susceptible strains of Gram-positive microorganisms. The bactericidal action of dalbavancin results primarily from inhibition of cell-wall biosynthesis. Specifically, dalbavancin prevents incorporation of N-acetylmuramic acid (NAM)- and N-acetylglucosamine (NAG)-peptide subunits from being incorporated into the peptidoglycan matrix; which forms the major structural component of Gram-positive cell walls. The large hydrophilic molecule is able to form hydrogen bond interactions with the terminal D-alanyl-D-alanine moieties of the NAM/NAG-peptides, which is normally a five-point interaction. Binding of dalbavancin to the D-Ala-D-Ala prevents the incorporation of the NAM/NAG-peptide subunits into the peptidoglycan matrix. In addition, dalbavancin alters bacterial-cell-membrane permeability and RNA synthesis.