Question

immunology question

1. Why is it critical for complement proteins to be at a high concentration in the blood? In other words, what are the potential consequences were they NOT at high concentrations?

2. Why is it important that activated complement proteins have very short half-lives & that the body has mechanisms to be able to quickly inactivate activated complement?

Answer 1

Please find the answers below:

Answer 1: Complement system is a branch of immune-proteins in the blood which not only regulate the immune response of the body but also amplifies the activity of the host-immune response against invasion of pathogens. These complement proteins are present in large concentration in the blood in order to ensure the following:

1. Quick activation of the immune response against pathogen infection.
2. Ensurance of amplified immune response against rapid infection
3. Activation of multiple branches of the immune response simultaneously in order to achieve a multi-factorial immune effect in the body.

Thus, if these complement proteins are not present in a sufficiently high concentration, a rapid and amplified immune-response would not be achieved and the host might get infected with the pathogen.

Answer 2: It has been seen both pre-clinically and clinically that the complement-mediated activation of immune response requires activation of a series of biochemical reactions. Many short-lived complement proteins take crucial part in these serial biochemical reactions. Hence, it is mandatory that activation of these short-lived complement proteins with low half-lives might take place so that the serial chemical reactions might proceed and final activation of the complement system may take place.