Changes in the Titer of Bombyxin‐Immunoreactive Material in Hemolymph during the Postembryonic Development of the Silkmoth Bombyx mori

Monoclonal antibodies were raised against pure, native bombyxin-II (bombyxin-II antibody) and against a synthetic nonapeptide corresponding to the amino-terminus of the C-peptide of the bombyxin precursor protein (C-peptide antibody). The bombyxin-II antibody recognized both bombyxin and probombyxin. A radioimmunoassay for bombyxin using the bombyxin-II antibody was developed, and developmental change in the titer of bombyxin immunoreactivity in the Bombyx hemolymph was investigated. The titer was low and almost constant during the fourth and early fifth instars. In the male, the titer rose abruptly 3 days after the beginning of wandering. One day after pupation it rose again steeply to reach the maximal level which lasted until the middle of the developing adult stage. The titer decreased thereafter and increased again at adult emergence. In the female, the pattern of titer fluctuation was similar to that in the male, but the female titers during pupal-adult development were 2-3 times higher than the male titers.