受動免疫 受身免疫
an impermanent form of acquired immunity in which antibodies against a disease are acquired naturally (as through the placenta to an unborn child) or artificially (as by injection of antiserum)
疾患に対する抗体が（誕生前の子供への胎盤を通してのように）自然に、もしくは（抗血清の注射のように）人工的に獲得される、という後天的免疫の一時的な形態