ANTIGENIC DETERMINANT IN HUMAN COAGULATION FACTOR-IX - IMMUNOLOGICAL SCREENING AND DNA-SEQUENCE ANALYSIS OF RECOMBINANT PHAGE MAP A MONOCLONAL-ANTIBODY TO RESIDUE-111 THROUGH RESIDUE-132 OF THE ZYMOGEN

  • 1 May 1986
    • journal article
    • research article
    • Vol. 67  (5) , 1344-1348
Abstract
As an approach to the study of structure-function relationships in the normal and defective forms of human coagulation factor IX, we have begun to develop a series of monoclonal antibodies against specific sites on the protein. Zymogen and activated forms of normal factor IX were used initially as antigen for the preparation of monoclonal antibodies. Recombinant phage were prepared by cloning small (50- to 500-nucleotide) random DNA fragments from the coding region of a factor IX cDNA clone into the expression vector .lambda. gt11. Immunological screening of these recombinants with mixtures of monoclonal antibodies identified several immunoreactive phage. Further analysis showed that the monoclonal antibody designated IX-30 was generating the positive signals at a frequency of .apprx. 1/2,500 recombinants. Subcloning and sequence analysis of the inserted DNA in the immunoreactive phage revealed overlapping in-frame insertions, from which it could be inferred that the site in factor IX recognized by IX-30 is confined to residues 111 through 132 in the light chain. Similar mapping with other monoclonal antibodies should provide additional probes for the protein structure of human factor IX.