This video shows detail of cytotoxic reaction i.e., hypersensitivity II. Moreover, it deals with different examples and their mechanisms. A very comprehensive video for the topic! Timeline 0:00 Introduction 0:03 Contents of video 0:11 overview of hypersensitivity reaction 2:16 Hypersensitivity II (cytotoxic reaction) 4:01 Mechanism of reaction 6:26 IgG against penicillin 7:08 Events that happen after complement activation. 7:56 Classical pathway for complement activation. 9:14 Function of C3 10:16 Function of C5 11:54 IgG/IgM against quinine 12:42 IgM against mycoplasmas 13:13 Antibodies against fetus 14:07 Antibodies against M proteins