抄録
The tuberculin reaction, classical form of delayed type hypersensitivity, is defined as an immunologically determined inflammatory response characterized mainly by delayed onset of the reaction and by a mononuclear cell infiltration at the reaction site. These two characteristics are analysed in this review in relation to the mechanism of manifestation of the tuberculin skin reaction.
Many evidences in the passive transfer of tuberculin sensitivity showed that the passive sensitization could be established without lag by injecting.intravenously the mononuclear cells from sensitized animals to normal in the absence of demonstrable serum antibody and that the immunologically competent cells would be sensitized lymphocyts transformed from thymus-dependent lymphocytes. After leaving the regional lymph nodes where they were produced, the sensitized cells start to circulate through the whole body to establish the over-all sensitization to tuberculin.
Further experiments in which passive transfer was combined with desensitization or with labelling of donor or recipient demonstrated that the circulating sensitized cells interacted directly with the tuberculin injected intradermally and remained there at the contact site, reaching in several hours (within 6 hours) the necessary numbers for elicitation of the skin reaction. This immunologically specific process hardly manifests a visible reaction. The majority of the infiltrating cells at the reaction site consists of non-specific mononuclear cells, with a small portion of specifically sensitized cells, even when the reaction reaches the maximal intensity. The non-specific cells play a major role for the visible expression of the reaction, coming almost entirely from an actively dividing cell population through the blood stream. Thus the tuberculin reaction consists of 2 steps, specific and non-specific.
