Based on your understanding of the content in Practical (Complement-mediated lysis of red blood cells), if you were to repeat this experiment again, what reaction could you include to serve as a positive control and why would this be an appropriate positive control?

For background knowledge the results of the experiment conducted are:

1. Coombs tube #1 normal serum, saline and sheep red blood cels (SRBCs) ---------> Degree of hemolysis: 0-1+ , Active component from normal serum can cause SRBC lysis via the alternative pathway

2. Coombs tube #2: tube normal serum heat inactivated, saline and sheep red blood cells ------------> Degree of hemolysis:0, Inactivate complement cannot lyse SRBCs via alternative pathway.

3. Coombs tube #3: immune serum, saline and sheep red blood cells (SRBCs) -----------> Degree of hemolysis: 1-3+, Immune system containing antibodies and active complement lyses SRBCs via classical and alternative pathways.

4. Coombs tube #4: Immune serum heat inactivated, saline and red blood cells (SRBCs) ---------> Degree of hemolysis: 0, Immune serum containing antibodies and inactive complement cannot lyse SRBCs

5. Coombs tube #5: Normal serum, immune serum heat inactivated in sheep red blood cells (SRBCs) ---------> Degree of hemolysis: 1-3+, complement from normal serum, antibodies from immune serum cause SRBC lysis via classical and alternative Pathways

6. Coombe tube #6: Normal serum heat inactivated, immune serum heat inactivated and sheep red blood cells (SRBCs) ---------> Degree of hemolysis:0, inactivated complement in both normal and immune serum can not lyse SRBCs

7. Coombs tube #7: saline in sheep red blood cells (SRBCs) ---------> Degree of hemolysis:0, SRBCs alone, Control Complement absent, Antibodies absent