Purified immunoglobulin-related factor, novel monoclonal antibodies, hybridoma cell lines, processes and applications

A process for the preparation of an individual protein or a fragment of the individual protein, the individual protein or the fragment of the individual protein possessing immunoglobulin E binding and immunoglobulin E synthesis suppressing activity, comprising the steps of:

• obtaining a culture supernatant of a continuous human B-cell line, said continuous human B-cell line capable of expressing immunoglobulin E binding factors and receptors for immunoglobulin E;
• contacting a solution from said continuous human B-cell line culture supernatant containing said immunoglobulin E binding factors with a carrier material bearing monoclonal antibodies which bind to said immunoglobulin E binding factors, said monoclonal antibodies being secreted by any of the hybridoma cell lines 207.25 A.4.4/30, 207.25 A4.4/45 or 208.25 D.2/94;
• allowing said immunoglobulin E binding factors to bind to said monoclonal antibodies on said carrier material;
• removing unbound proteins and other foreign substances;
• selectively splitting off said immunoglobulin E binding factors from said monoclonal antibodies on said carrier material;
• purifying by isolation said immunoglobulin E binding factors:
• and
• separating said purified immunoglobulin E binding factors to obtain individual optionally glycosylated proteins and fragments thereof;
• wherein the individual protein;
• (a) is a constituent of a substantially pure human immunoglobulin E binding factor,
• (b) possesses immunoglobulin E binding and immunoglobulin E synthesis suppressing activity,
• (c) is homogeneous as determined by SDS-PAGE analysis,
• (d) has an apparent molecular weight of 25-28 kD as determined by SDS-PAGE analysis, and
• (e) is optionally glycosylated, and
• wherein the fragment of the individual protein;
• (f) is a constituent of a substantially pure human immunoglobulin E binding factor,
• (g) possesses immunoglobulin E binding and immunoglobulin E synthesis suppressing activity,
• (h) is homogeneous as determined by SDS-PAGE analysis,
• (i) has an apparent molecular weight of 10-20 kD as determined by SDS-PAGE analysis, and
• (j) is obtainable by partial enzymatic digestion of said substantially pure immunoglobulin E binding factor.