Which of the following Fibrinolytic is antigenic?

The clinically important fibrinolytic are: 1. Streptokinase 2. Urokinase 3. Alteplase (rt-PA) 4. Reteplase 5. Tenecteplase Streptokinase: It is obtained from Beta hemolytic Streptococci group C. It is inactive as such: combines with circulating plasminogen to form an activator complex which then causes limited proteolysis of other plasminogen molecules to plasmin. Antistreptococcal antibodies present due to past infections inactivate a considerable fraction of the initial dose of Stk: a loading dose is necessary for the beginning. Its t1/2 is estimated to be 30-80 min. Streptokinase is antigenic; can cause hypersensitivity reactions and anaphylaxis, especially when used second time in a patient. Repeat doses are also less effective due to neutralization by antibodies. Fever is common, hypotension and arrhythmias are reported.