小儿出生后,都要接长不短地打预防针。为什么小儿打了预防针后就有了免疫功能而能够不得相应的传染病呢?这是因为当细菌、病毒等微生物侵入人体后,体内会产生一种能抵抗这些有害微生物的物质即“抗体”,当微生物再次侵入人体时,这种抗体就会加以“抵抗”,以消除它对人体的侵害。微生物入侵 After a child is born, have to take a long and short to prevent the needle. Why do children have immunization after vaccination can not have the corresponding infectious disease it? This is because when bacteria, viruses and other microorganisms invade the body, the body will produce a substance that can resist these harmful microorganisms that “antibodies” When the microorganism invades the human body again, the antibody will be “resisted” to eliminate it against the human body. Microbial invasion