IMMUNOCYTOCHEMICAL LOCALIZATION OF ANTIGENS IN B. CEREUS T SPORES¹

Abstract

The application of i m n o g o l d labeling for the localization of antigens on Bacillus cereus Tspores is described. Ultrathin cryosectiom of B. cereus Tspores were labeled with rabbit anti-B. cereus T spore serum and protien A-gold conjugate, and viewed in a transmission electron microscope. Antigens were located throughout the spore exosporium and also in the spore coat and protoplast. The higher density of gold particles in the exosporium indicates that the exosporium is very antigenic and was the major antigen when whole, formalin-treated, spores were injected into rabbits. The presence of label in the interior structure suggests spores may have been degraded by the animal upon injection, permitting exposure of interior antigens. 'Paper number FSR93-32 of the Journal Series of the Department of Food Science, North Carolina State University, Raleigh, NC 27695-7624. The use of trade names in this paper does not imply endorsement by the North Carolina Agricultural Research Service nor criticism of similar ones not mentioned.

Monoclonal antibodies for use in detection of Bacillus and Clostridium spores

“…Previous research with B. cereus spores has shown the exosporium to contain spore-specific antigens which are not present on the cells (7). Polyclonal antibodies made against B. cereus spores which reacted with a range of Bacillus spores, but not vegetative cells, were found to be located primarily on the exosporium (5). B. cereus and B. megaterium spores have similar hexagonally ordered lattice structures in the basal layers of their exosporia (3).…”

“…Ultrathin (ca. 100-m) cryosections of spores for immunological labeling with colloidal gold were prepared according to the method of Chang and Foegeding (5). B. cereus T and C. sporogenes PA3679 spores from the same stock as had been used for the antigen were used for these experiments.…”