Answer: CELL-MEDIATED
Explanation: Cell-mediated immune reaction is a type of immune response that is characterised by beneficial host response involving an expanded population of specific T-cells (a type of white blood cell that plays central role in immune response) which in the presence of antigens produce cytokines locally.(cytokines are any of a number of substances, such as interferon, interleukin, and growth factors, which are secreted by certain cells of the immune system and have an effect on other cells.)
Secondary contact activates a type of cell mediated reaction that made the child's father to develop poison ivy.