STOP YOU FROM GETTING INFECTIONS
1)When you are infected with a new pathogen it can take WBC a while to produce antibodies to deal with it. In that time you can get very ill or maybe die.
2)To avoid you could be vaccinated against some diseases e.g polio or measles.
3)involves getting injected with a dead/inactive/weakend pathogens into the body. These carry antigens, even though they are harmless they trigger an immune response. WBC produce antibodie to attack them.
4)Some WBC remain in blood called memory cells ifsame pathogen appears antibodies…