th1 immune response

one of the branches of the immune system. The TH1 response involves a subset of CD4 lymphocytes called TH1 cells that secrete IL-1, IL-2 and gamma interferon, and which enhance the cell-mediated immune response (action of CTL and natural killer cells) and inhibit TH2 cell activity and the humoral immune response . TH1 activity is especially effective against agents that have infected cells (e.g. cell-associated HIV).