(四)第Ⅳ型变态反应(迟发型或细胞介导型)参与本型反应的免疫物质不是体液抗体,而是致敏淋巴细胞,属于机体对某些抗原物质的一种细胞免疫反应。致敏机体与有关抗原接触后,12～24小时才开始出现反应,至58～72小时达高峰,数日后渐消退,故称此反应为迟发型。1.发生机制当机体受到某种抗原刺激 (D) Type IV allergy (delayed type or cell-mediated type) The type of response to the immune substance is not a humoral antibody, but sensitized lymphocytes, belonging to the body of some antigenic substances in a cellular immune response. Sensitization of the body after contact with the antigen, 12 to 24 hours before the reaction began to reach 58 to 72 hours peaked a few days later subsided, it said the reaction was delayed type. 1. The mechanism occurs when the body is stimulated by some kind of antigen