Hypersensitivity in Guinea Pigs to Oral Fusospirochetal Organisms

Abstract

Guinea pigs inoculated in the groin with washings from deep periodontal pockets developed fluctuant abscesses usually after one week. Exudate, aspirated from these abscesses and found to be rich in the fusospirochetal complex of organisms, provided infectious inoculum for challenges, heat killed sensitizing antigen and a cell-free exudate extract used for skin testing. Guinea pigs infected with the fusospirochetal exudate demonstrated a delayed, tuberculin-like dermal response to an intradermal inoculation of 0. 1 ml of cell-free extract prepared from the exudate. The dermal reaction was enhanced when complete adjuvant was added to either a viable inoculum or to a heat killed antigen prepared from the exudate. Four successive infectious challenges also enhanced the degree of delayed dermal response. Anaphylactic shock was demonstrated when cell-free extract was inoculated intravenously into guinea pigs showing strong delayed dermal reactions, suggesting the coexistence of both immediate and delayed hypersensitivity in these experiments. The dermal response was differentiated from the Shwartzman reaction and was passively transferred with lymphoid and splenic cells from sensitive guinea pig donors to nonsensitized recipients. Guinea pigs sensitized with whole exudate antigen and guinea pigs challenged with infectious fusospirochetal exudate were more sensitive to a cell-free extract of Bacteroides melaninogenicus than to extracts of several other organisms isolated from the fusospirochetal complex. It is suggested that hypersensitivity may alter the host-parasite relationship in periodontal disease.