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Knowledge about Immunity

In order to understand allergy, it is necessary to know the function of normal immunity at first. We will explain the process of invasion of dangerous pathogens such as bacteria and virus into the body and the working of immunity.

Commentary video   This video is a summary of this item for easy understanding.

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Pathogen invasion

When pathogens such as virus or bacteria invades the body, the first moving functions are "macrophage" and "dendritic cell". While attacking pathogens, they activate themselves by secreting a substance called "cytokine" or call up cells that attack pathogens such as "neutrophils". Our throat hurts when we have a cold because macrophages are activated. In addition, a yellow runny nose comes out because the neutrophil discharges the remains of the attacked pathogens.

Antigen presentation

When pathogens invades the body many times, macrophages and dendritic cells communicate information about the pathogens to "helper T cells". This is called "antigen presentation". Helper T cell is the cell that orders to remove foreign bodies. There are several types of helper T cells. If the danger is high, information will be sent to "Th 1" and the low things to "Th 2". We will explain this later. Here, pathogens are highly dangerous, so Antigen presentation to Th1.

Antibody generation and second attack

After antigen presentation, Th1 makes "B cell" make "antibody".
An antibody is a substance that binds to a specific "antigen" and attacks an antigen. However, the antigens here means pathogens such as viruses and bacteria, and "IgG antibody" are made in this time.

Killer T cells

Th1 makes B cells make not only antibodies, but also "killer T cells" cells that destroy pathogen-infected cells and pathogens.

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