Immunological properties of chemically produced fragments of rye grass pollen extract

Two fragment pools, one of MW greater than 10,000 and the other of MW between 1,000 and 10,000, were prepared by the sequential treatment of rye grass pollen extract with cyanogen bromide (cleavage at Met-X) and 2-nitro-5-thiocyanobenzoic acid (cleavage at X-Cys). Electrophoretic analysis of the two pools showed that none of the major components of the whole extract remained intact. Characterisation of the two fragment pools by radioimmunoassay showed that whilst they both lost the ability to bind to human anti-rye IgE antibodies, they largely retained their reactivity towards both human and mouse anti-rye IgG antibodies. In addition, the higher molecular weight pool retained its ability to stimulate extract-specific T cells, after accessory cell processing. This separation of the immunological properties of rye grass pollen extract by chemical cleavage is seen as a basis for the development of novel immunotherapy agents.