Immunogold Detection of Polyhedrin, p10 and Virion Antigens in Autographa californica Nuclear Polyhedrosis Virus-infected Spodoptera frugiperda Cells

SUMMARY Protein A-gold labelling was used to detect and locate particles and two major late antigens, polyhedrin and pl0, of Autographa californica multiply-enveloped nuclear polyhedrosis virus in thin sections of Spodoptera frugiperda cells. With polyhedrin antiserum, gold label was found over viral occlusion bodies (polyhedra), but not over the fibrous structures associated with polyhedron morphogenesis and previously thought to consist of precondensed polyhedrin. In contrast, with pl0 antiserum, gold label was found only over these fibrous structures in the nucleus and similar structures in the cytoplasm. This suggests that pl0 is a major constituent of the fibrous structures and may, therefore, play an important role in polyhedron morphogenesis.