| Abstract: | A comparison was made of the retention of three antigens PPD (protein purified derivative of tuberculin), HSA (human serum albumin) and HGG (human γ globulin) labelled with 131I in the skin of normal guinea-pigs. It was found that PPD was eliminated more rapidly than HSA or HGG in the first 24 hours after skin test. In contrast PPD was found to be more readily adsorbed to collagen and cellular tissues in vitro. The retention of these antigens at 24 hours in normal and sensitized guinea-pigs was also compared. It was found that PPD was retained in the tuberculin lesion as compared with normal skin, whereas HSA was eliminated more rapidly from a delayed-type hypersensitivity lesion to HSA when compared with normal skin. It was concluded that retention of PPD was probably not specific to delayed-type hypersensitivity but was related to the difference in character and severity of the inflammatory process, which itself was related to the chemical nature of the antigen involved. |
