A murine monoclonal antibody against rat atrial natriuretic factor (ANF) which cross-reacts with mouse ANF

A monoclonal antibody (MAb), 2H2, against rat synthetic atrial natriuretic factor (ANF) (Arg101-Tyr126) recognizes native ANF related peptides. The lack of reactivity of 2H2 with amino-terminal truncated ANF peptides implicates the two amino terminal arginine residues of ANF in the 2H2 epitope. Similarly, poor immunoreactivity of human ANF indicates the participation of isoleucine 110. Arginines 101 and 102 and isoleucine 110 may thus participate in a conformational epitope recognized by 2H2 or alternatively, substitution for, or elimination of these residues may alter the conformation of the 2H2 epitope. The MAb shows little cross-reactivity with extracts of rabbit atria but recognizes ANF related peptides in mouse and hamster atrial extracts. 2H2 also identifies immunoreactive ANF in histological sections of rat, mouse and hamster atria.