ovalbumin and murabutide

Emulsions play an important role in present-day subunit vaccine delivery. Squalane-based emulsion was formulated using surfactants viz., Pluronic F68, Span 85 along with Murabutide (MB) as immunepotentiator. Particle size and zetapotential of the final optimized emulsion was found to be 134 nm and -13 mV, respectively. The in vitro cellular uptake studies performed using fluorescein isothiocyanate (FITC)-labeled ovalbumin (OVA) clearly revealed the rapid uptake of antigen in the presence of emulsion. The in vivo subcutaneous studies involving measurement of OVA-specific IgG antibody titers, Th1/Th2 cytokines were performed and a marked up regulation in IL-2, IL-12 and IFN-γ cytokines indicate Th1 immune response. Results supported that the squalane-based delivery system enhanced the uptake of the antigen by immune cells and elicited humoral as well as cell-mediated immune response in mice. These results indicate the promising application of the new squalane based oil-in-water (O/W) emulsion as capable vaccine delivery system useful for vaccine development.

Topics: Acetylmuramyl-Alanyl-Isoglutamine; Adjuvants, Immunologic; Animals; Antigens; Cytokines; Drug Delivery Systems; Emulsions; Fluorescein-5-isothiocyanate; Hexoses; Mice; Mice, Inbred BALB C; Ovalbumin; Particle Size; Poloxamer; RAW 264.7 Cells; Squalene; Surface-Active Agents; Th1 Cells; Th2 Cells; Vaccines

Subunit vaccines are often poorly immunogenic, and adjuvants and/or delivery vehicles, such as polymeric microparticles (MPs), can be used to enhance immune responses. MPs can also be used to understand cell activation kinetics and the significant impact antigen and adjuvant release has on adaptive immune responses. By controlling antigen and adjuvant release, we can determine if it is important to have precise temporal control over release of these elements to optimize the peak and duration of protective immunity and improve vaccine safety profiles. In order to study the effect of tunable adjuvant or antigen delivery on generation of adaptive immunity, we used acetalated dextran (Ace-DEX) MPs. Ace-DEX MPs were used because their tunable degradation can be controlled based on polymer cyclic acetal coverage (CAC). Ace-DEX MPs of varying degradation profiles were used to deliver murabutide or ovalbumin (OVA) as a model adjuvant or antigen, respectively. When murabutide was encapsulated within Ace-DEX MPs to test for controlled adjuvant delivery, fast-degrading MPs exhibited higher humoral and cellular responses in vivo at earlier time points, while slow-degrading MPs resulted in stronger responses at later time points. When OVA was encapsulated within Ace-DEX MPs to test for controlled antigen delivery, fast-degrading MPs induced greater antibody and cytokine production throughout the length of the experiment. This differential response suggests the need for distinct, flexible control over adjuvant or antigen delivery and its impact on immune response modulation.

Topics: Acetylation; Acetylmuramyl-Alanyl-Isoglutamine; Adaptive Immunity; Adjuvants, Immunologic; Animals; Antigens; Cell Line; Cytokines; Dextrans; Female; Immunoglobulin G; Mice; Mice, Inbred C57BL; Ovalbumin; Vaccines, Subunit

A nonpyrogenic desmuramyl peptidolipid, 1-O-(L-alanyl-D-isoglutaminyl-L-alanyl-glycerol-mycolate), had previously been shown to be inactive as adjuvant in guinea pigs, but to be very active in stimulating nonspecific resistance. We now show that 1-O-(L-alanyl-D-isoglutaminyl-L-alanyl-glycerol-mycolate) is capable of enhancing or suppressing the immune responses in mice when injected with or before an antigen. In vivo suppression of the immune response to sheep erythrocytes was also observed with high doses of murabutide, a nonpyrogenic adjuvant-active N-acetylmuramyl-L-alanyl-D-isoglutamine analog. Chemiluminescence measurements with mouse spleen cells show a very strong activity of 1-O-(L-alanyl-D-isoglutaminyl-L-alanyl-glycerol-mycolate) by far superior to the effect obtained with the corresponding muramyl peptide, N-acetylmuramyl-L-alanyl-D-isoglutaminyl-L-alanyl-glycerol-myco late.

Topics: Acetylmuramyl-Alanyl-Isoglutamine; Adjuvants, Immunologic; Animals; Antibodies, Bacterial; Female; Guinea Pigs; Humans; Immunosuppressive Agents; Luminescent Measurements; Lymphocytes; Male; Mice; Mice, Inbred BALB C; Mice, Inbred DBA; Ovalbumin; Tetanus Toxoid