Cells Recovered from Human DTH Reactions: Phenotypic and Functional Analysis

Using the skin window chamber (SC) technique T cells were recovered from DTH reactions elicited by either PPD or Candida (CAN) in three healthy individuals. Analysis of representative panels of clones established in limiting dilution cultures from SC and blood disclosed a 2.6-, 10-, and 314-fold higher incidence of antigen-specific T cells in SC than in blood. Thirty CD4+ and 13 CD8+ antigen-specific clones were recovered from SC. Eight of 14 CD4+ clones displayed lectin-mediated cytotoxicity (as compared to 2/10 from blood) and 4/5 CD8+ clones were also cytotoxic. The CD4+ clones from SC, but not from blood could be divided into two groups, one producing IFN-γ and IL-2, and the other providing help for Ig synthesis. Among the CD8+ SC clones analyzed the noncytotoxic clone could provide help for Ig synthesis but produced no IFN-γ whereas the other four showed the opposite pattern. Analysis of the fluid phase of SCs from positive DTH reactions disclosed high levels of TNF and IFN-γ; neither was detected from SCʹs covering sites injected with nonspecific antigens.