ovalbumin and 3-3--dioctadecylindocarbocyanine

The present in-vivo study investigated the behavior and performance of differently charged poly(lactic‑co‑glycolic) acid microparticles (PLGA MP) as vaccination platform. For this purpose, particles loaded with ovalbumin (OVA) as model antigen were subcutaneously (s.c.) injected in SKH1 mice. The utilized SKH1 hairless mice exhibit a fully operative immune system and allow parallel imaging investigations due to the lack of hair. Usage of this species enabled the combination of two investigations within a single study protocol, namely noninvasive in-vivo imaging and immune responses directed towards the antigen. All treatments were well tolerated, no safety drop-outs occurred. The fate of the model antigen OVA as well as the PLGA particles was monitored using a dual dye approach (CF660C & DiR) by multispectral fluorescence imaging (msFI). A depot effect for the OVA antigen adsorbed to the MP surface could be observed for the positively charged MPs. The immune response against OVA was then analyzed. OVA alone did not induce an immune response, whereas the positively charged as well as the neutral MP induced a strong and consistent humoral immune response with a clear favor of IgG1 over IgG2a subclass antibodies. In contrast, negatively charged MP were not able to induce measurable antibody responses. Cellular immune response was weak and inconsistent for all treated groups, which verifies previous in-vitro results conducted with the herein described microparticulate antigen platform. In conclusion, the characterization of the in-vivo performance yielded valuable information about antigen and carrier fate after application. The presented adjuvant platform is capable of inducing strong T

Topics: Adjuvants, Immunologic; Animals; Antigens; Carbocyanines; Cytokines; Drug Carriers; Drug Evaluation, Preclinical; Fluorescent Dyes; Immunoglobulin G; Lactic Acid; Male; Mice, Hairless; Ovalbumin; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer

Previous studies from this laboratory have used antisera to aldehyde-conjugated ovalbumin to localize ovalbumin-like immunoreactivity within a subpopulation of sensory neurons. We have now combined retrograde tracing and immunohistochemical procedures to identify the tissues innervated by sensory neurons which are either immunoreactive or non-immunoreactive for ovalbumin. The fluorescent tracer Di-I was administered to feather follicles, flexor ulnar muscle, subdermis, expansor secundariorum, heart and liver and identified seven days later within corresponding dorsal root ganglia. Most neurons innervating the follicles had large cell somata, and fewer than 3% were immunoreactive for ovalbumin. In contrast, most sensory neurons projecting to subdermis, muscle and expansor secundariorum muscle were of a medium diameter. Approximately 25% of those neurons projecting to the expansor secundariorum, and 60% projecting to the subdermis and muscle, were immunoreactive for ovalbumin. Sensory neurons innervating heart and liver were the smallest, and only 8% were immunoreactive for ovalbumin. The study indicates that sensory neurons innervating different organs have somata with significantly different sizes, suggesting a functional specificity. Moreover, neurons demonstrating either the ovalbumin-IR positive or negative phenotypes show distinct peripheral projections, suggesting that this phenotype may be at least partially controlled by retrograde signals derived from the cells they innervate.

Topics: Afferent Pathways; Animals; Carbocyanines; Cell Size; Chickens; Feathers; Fluorescent Antibody Technique; Fluorescent Dyes; Ganglia, Spinal; Heart; Liver; Muscles; Nerve Tissue Proteins; Neurons, Afferent; Organ Specificity; Ovalbumin; Phenotype; Wings, Animal