Delayed hypersensitivity in mice induced by intravenous sensitization with sheep erythrocytes: evidence for tuberculin type delayed hypersensitivity of the reaction.

Delayed hypersensitivity (DH) reaction can be induced in mice by intravenous sensitization with sheep erythrocytes (SRBC). However, as the sensitizing procedure is quite different from a usual mode of sensitization for DH using complete Freund's adjuvant (FCA), the nature of this reaction has been a matter of controversy. In an attempt to characterize this reaction, we placed special interest on two possibilities regarding the nature of this reaction; Jones-Mote reaction or tuberculin type DH. From the kinetics study on the DH after challenge, the DH reaction to SRBC in mice by intravenous sensitization was clearly distinguished from the Arthus reaction. The dose-response pattern of this reaction also suggested that the contribution of Arthus reactivity to delayed reactivity was negligible. Cell reconstitution experiments revealed this DH to be quantitatively thymus cell dependent. Furthermore, this DH required macrophages at its manifestation stage, and appearance of basophil infiltration at the lesion was absent. In addition, strain difference and ageing of host mice influenced the DH reaction in exactly the same fashion in which these factors influence the tuberculin type-DH induced by subcutaneous sensitization with methylated human serum albumin (MHSA) in FCA. Taken collectively, it was concluded that this DH reaction can be categorized as the tuberculin type.