system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What are the different bloodtypes, the differences between them and why are can you not mix them?
gpt
It boils down to the fact that different blood types have different proteins expressed on the cell membrane. The reason you can’t mix them is because if you receive a different blood type (with different proteins) your body will see them as foreign invaders and activate your immune system to attack the blood, which can be fatal.