ovalbumin and 4-4-difluoro-4-bora-3a-4a-diaza-s-indacene

In this study the relation between the ability of protein self-association and the surface properties at air-water interfaces is investigated using a combination of spectroscopic techniques. Three forms of chicken egg ovalbumin were obtained with different self-associating behavior: native ovalbumin, heat-treated ov-albumin-being a cluster of 12-16 predominantly noncovalently bound proteins, and succinylated ovalbumin, as a form with diminished aggregation properties due to increased electrostatic repulsion. While the bulk diffusion of aggregated protein is clearly slower compared to monomeric protein, the efficiency of transport to the interface is increased, just like the efficiency of sticking to rather than bouncing from the interface. On a timescale of hours, the aggregated protein dissociates and adopts a conformation comparable to that of native protein adsorbed to the interface. The exerted surface pressure is higher for aggregated material, most probably because the deformability of the particle is smaller. Aggregated protein has a lower ability to desorb from the interface upon compression of the surface layer, resulting in a steadily increasing surface pressure upon reducing the available area for the surface layer. This observation is opposite to what is observed for succinylated protein that may desorb more easily and thereby suppresses the buildup of a surface pressure. Generally, this work demonstrates that modulating the ability of proteins to self-associate offers a tool to control the rheological properties of interfaces.

Topics: Adsorption; Air; Animals; Boron Compounds; Chickens; Hot Temperature; Kinetics; Microscopy, Fluorescence; Ovalbumin; Ovum; Pressure; Protein Conformation; Protein Structure, Secondary; Proteomics; Rheology; Spectrometry, Fluorescence; Spectroscopy, Fourier Transform Infrared; Static Electricity; Surface Properties; Time Factors; Water

Drainage and retention of brain-derived antigens are important factors in initiating and regulating immune responses in the central nervous system (CNS). We investigated distribution, immunological processing and retention of intracerebrally infused protein antigen, ovalbumin (OVA), and the subsequent recruitment of CD8(+) T cells into the CNS. We found that protein antigens infused into the CNS can drain rapidly into the cervical lymph node and initiate antigen-specific immune response in the periphery. A portion of the antigens are also retained by CD11b/MAC-1(+) cells in the brain parenchyma where they are recognized by antigen-specific CD8(+) T cells.

Topics: Animals; Antigen Presentation; Boron Compounds; Brain; CD11b Antigen; CD8-Positive T-Lymphocytes; Cell Movement; Egg Proteins; Epitopes, T-Lymphocyte; Female; Fluorescent Dyes; Immunohistochemistry; Injections, Intraventricular; Lymph Nodes; Macrophage-1 Antigen; Mice; Mice, Inbred C57BL; Neck; Ovalbumin; Peptide Fragments