Question

1. How do B and T cells recognize specific antigens?
2. What are two types of acquired immunity? Describe each and give an example.
3. Explain the process from the activation of the B cell to the production of antibodies.
4. How do cytotoxic T cells kill infected cells?

Answer 1

Answer 1) T and B cells have the same mechanism of recognition and binding to antigens, through a complementary receptor mechanism where the antigen binds with the complex of two protein chains which is known as antigen receptors nd is present on T and B cells. This helps in binding to the specific antigen on the pathogen which is infecting the body

Answer 2)There are two types of acquired immunity are:

1. Active immunity - Example: Antibodies made after body is exposed to an infection
2. Passive immunity.- Example: Antibodies are not produced in the body they are inserted in body from outside such as transferred from mother to baby through milk, vaccination, etc.

Answer 3) The activation of B cells generally occurs in spleen and lymph nodes which are also known as the secondary lymphoid organs. Once the maturation of B cells takes place in bone marrow, they get transferred to secondary lymphoid organs through blood. In blood B cells m=intract with antigen and they get activated when the antigen gets attached to the B cells receptor

B cell activation occurs in the secondary lymphoid organs (SLOs), such as the spleen and lymph nodes. After B cells mature in the bone marrow, they migrate through the blood to SLOs, which receive a constant supply of antigen through circulating lymph.B cells are activated when their B cell receptor (BCR) binds to either soluble or membrane-bound antigen.

Answer 4) T cells release two types of cytotoxic proteins:

1. Pore-forming protein perforin- It induces apoptosis
2. The granzymes- punches a hole in the cell membrane of antigen which allows the movement of granzymes inside the cell.

By this two mechanisms T cell kills antigen