The use of hairless (IAF/HA-HO) guinea pigs for the determination of delayed-type hypersensitivity to tuberculin

Guinea pigs are a classic animal model for studying delayed-type hypersensi tivity (DTH) reactions. However, skin irritation due to hair removal can in terface with the evaluation of the modulation of these responses by various mediators. A DTH model using hairless (IAF/HA-HO) guinea pigs, sensitized with complete Freund's adjuvant and repeatedly skin tested with tuberculin, purified protein derivative, (PPD) has therefore been developed. At 10 wee ks after sensitization, intradermal PPD elicited minimal erythema at 6 h, w hich increased over the next 18 h to a maximum at 24 h, and declined by 48 h. The response could be quantified by bioassay using graded doses of PPD. Reactions at 24 h were characterized by predominantly mononuclear cell deep and superficial dermal infiltrates. Dermal DTH in hairless guinea pigs is thus, grossly and histologically similar to that seen in Hartiey guinea pig s. (C) 2001 Elsevier Science B.V. All rights reserved.