Peptides and autoimmune disease

Immunohistochemical study of myelin sheaths formed by oligodendrocytes interacting with dissociated dorsal root ganglion neurons in culture

The addition of central nervous system (CNS) glial cells to dissociated networks of rat dorsal root ganglion neurons in tissue culture provided a useful system for the study of CNS myelin sheath formation. The CNS myelin basic proteins (BP) and proteolipid protein (PLP) were demonstrable in these cultures by immunoperoxidase techniques. Both BP and PLP were detectable in myelinating oligodendrocytes and CNS myelin sheaths. Anti-BP serum and anti-PLP serum were useful immunohistochemical staining reagents for the identification of myelinating oligodendrocytes and CNS myelin sheaths in tissue culture.

Prediction of protein antigenic determinants from amino acid sequences

A method is presented for locating protein antigenic determinants by analyzing amino acid sequences in order to find the point of greatest local hydrophilicity. This is accomplished by assigning each amino acid a numerical value (hydrophilicity value) and then repetitively averaging these values along the peptide chain. The point of highest local average hydrophilicity is invariably located in, or immediately adjacent to, an antigenic determinant. It was found that the prediction success rate depended on averaging group length, with hexapeptide averages yielding optimal results. The method was developed using 12 proteins for which extensive immunochemical analysis has been carried out and subsequently was used to predict antigenic determinants for the following proteins: hepatitis B surface antigen, influenza hemagglutinins, fowl plague virus hemagglutinin, human histocompatibility antigen HLA-B7, human interferons, Escherichia coli and cholera enterotoxins, ragweed allergens Ra3 and Ra5, and streptococcal M protein. The hepatitis B surface antigen sequence was synthesized by chemical means and was shown to have antigenic activity by radioimmunoassay.

Precise determination of protein antigenic structures has unravelled the molecular immune recognition of proteins and provided a prototype for synthetic mimicking of other protein binding sites

Intensive research in the author's laboratory had culminated in the determination and synthesis of all the antigenic sites of myoglobin in 1975 and of lysozyme in 1978. Very recently most of the antigenic sites of serum albumin were also localized and synthesized. These investigations provided the first unique insight into the molecular features responsible for the immune recognition of protein antigens and of the factors which determine and regulate the antigenicity of the sites. But moreover, these studies have charted a multi-approach chemical strategy for investigation and synthetic duplication of protein binding sites. Furthermore, the concept of 'surface-simulation' synthesis, which we introduced and developed during our determination of the antigenic structure of lysozyme, has provided a remarkable dimension of unlimited versatility for the synthetic mimicking of any type of protein binding sites. In this concept, the spatially adjacent residues of a protein binding site are linked directly via peptide bonds with appropriate spacers into a single peptide which does not exist in the protein but mimicks a surface region of it. This has proved to be a powerful concept in protein molecular recognition and has opened up many untapped avenues in investigation, duplication and perhaps manipulation of a variety of protein activities. In fact, binding sites representing other protein activities (including antibody combining sites) have or are now being mimicked synthetically in our laboratory by the concept of surface-simulation synthesis.