Most continuous antigenic determinants of tobacco mosaic virus protein (TMVP), myoglobin and lysozyme correspond to those surface regions in the protein structure, as determined by X-ray crystallography, which possess a run of high-temperature factors along the polypeptide backbone, that is, a high segmental mobility. The mobility of an antigenic determinant may make it easier to adjust to a pre-existing antibody site not fashioned to fit the exact geometry of a protein. The correlation found between temperature factors and antigenicity is better than that between hydrophilicity and antigenicity.

A B-cell epitope is the three-dimensional structure within an antigen that can be bound to the variable region of an antibody. The prediction of B-cell epitopes is highly desirable for various immunological applications, but has presented a set of unique challenges to the bioinformatics and immunology communities. Improving the accuracy of B-cell epitope prediction methods depends on a community consensus on the data and metrics utilized to develop and evaluate such tools. A workshop, sponsored by the National Institute of Allergy and Infectious Disease (NIAID), was recently held in Washington, DC to discuss the current state of the B-cell epitope prediction field. Many of the currently available tools were surveyed and a set of recommendations was devised to facilitate improvements in the currently existing tools and to expedite future tool development. An underlying theme of the recommendations put forth by the panel is increased collaboration among research groups. By developing common datasets, standardized data formats, and the means with which to consolidate information, we hope to greatly enhance the development of B-cell epitope prediction tools.

Antibodies were isolated from the yolks of hens that were immunized with a variety of plant viruses by the use of polyethylene glycol (PEG). A concentration of 3.5% of the polymer caused the lipids and vitellin to separate, and the IgY was then precipitated with 12% PEG. The titre of the isolated antibody appears to remain at a high level after cessation of the course of immunization. Antibodies derived from the yolks of hens appear to have titres similar to those found in serum of rabbits immunized simultaneously. The observation made by several authors that a high salt concentration enhances fowl serum antibody precipitin titres could not be corroborated with 'yolk' antibodies directed against several plant viruses.

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