USE OF GOLD-LABELED OVALBUMIN TO CORRELATE ANTIGEN DEPOSITION AND LOCALIZATION WITH TISSUE-RESPONSE

This study was performed to evaluate a technique for correlating the l ocation of antigen within sensitized tissues with physiological respon se. Guinea pigs actively sensitized by intraperitoneal injection of ov albumin (OVA) were euthanized, and urinary bladders were removed. Gold beads (18 nM diameter) were conjugated to OVA (OVA-Au) and bovine ser um albumin (BSA-Au). Bladder tissue was suspended in tissue baths, exp osed to OVA, OVA-Au, BSA, and BSA-AU, and tissue contraction and hista mine release were determined. Bladder tissues were examined by electro n microscopy to determine distribution of gold-labeled antigen at 1 an d 5 min after exposure. Exposure of bladder tissue from sensitized gui nea pigs to OVA stimulated concomitant contraction and histamine relea se which reached maximal levels within 3 min; bladder tissue from cont rol, nonsensitized guinea pigs did not respond to OVA. BSA failed to s timulate response from OVA-sensitized or control bladder tissue. Label ed antigen was adhered to mucosa of sensitized bladder tissue 1 min af ter exposure to OVA-Au. OVA-Au was present within the mucosa and submu cosa of sensitized tissues within 5 min. OVA-Au did not adhere to, or become internalized by, control tissues, and BSA-Au did not adhere to, or become internalized by, any tissues. Labeling of antigen with gold allowed the location of antigen within tissues to be determined and d id not affect the response of sensitized tissues to antigen exposure. (C) 1997 Elsevier Science Inc.