Question

write down the steps of action of complement system against bacterium​

Answer 1

The complement system, also known as complement cascade, is a part of the immune system that enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promote inflammation, and attack the pathogen's cell membrane. It is part of the innate immune system,[1] which is not adaptable and does not change during an individual's lifetime. The complement system can, however, be recruited and brought into action by antibodies generated by the adaptive immune system.

Answer 2

1. Membrane attack – by rupturing cell wall of bacteria. (Classical Complement Pathway)
2. Phagocytosis – by opsonizing antigens. C3b has most important opsonizing activity. ...
3. Inflammation – by attracting macrophages and neutrophils. (Lectin pathway)