Work in pairs. In turns ask and answer the questions you have made

7 Look at the dialogue below. Complete the student’s answers with the sentences from the box.

AT he equivalent number of lymphoid cell clones with their unique receptors is required for the recognition of their multitude.

B Due to this overwhelming majority of immune responses the organism needs cooperation of several specialized cells such as B-lymphocytes, T-lymphocytes, antigen-presenting cells.

C These molecules are called antigens and the specific tools of the immune system are antigen-specific lymphocyte receptors.

D As a rule, epitopes are located in the most mobile and configurable parts of quite rigid antigen structures.

E Antigens are capable of inciting immune response in the organism by specifically binding to the lymphocytic antigen-specific receptors.

F For example, gelatin is a high molecular weight protein devoid of tertiary structure, and, consequently, it is either non-antigenic or very weak antigen.

G it maintainsgenetic homeostasis so the organism can survive

H that may be recognized by the receptors of T- and B-lymphocytes and may generate immune response

Examiner: Let’s talk about antigens. What is the main function of the

immune system?

Student: Well. 1 ……….

Examiner: How can the immune system fight against different pathogens?

Student: By meansofa mechanism capable of producing a host of special tools, which bind pathogens neutralizing them. Each tool is specifically complementary to one out of a billion various biopolymer molecular types. 2……….

Examiner: What structural substance can be called antigenic?

Student: A substance is antigenic provided it has a three-dimensional structure that may be recognized by the receptors of T- and B-lymphocytes and may generate immune response.. 3 ……….

Examiner: Can high molecular weight substances be non-antigenic?

Student: Yes, they can provided they have a flat structure. 4 ……….

Examiner: So what are antigens?

Student: They are a wide variety of natural and biosynthetic molecules ranging in size between 1 and 10 kD. 5 ……….

Examiner: What is known as epitopes? And where are they located?

Student: This is the minimal structural unit of an antigen recognizable for antibodies and lymphocyte antigenic receptors. 6 ……….

Examiner: How many clones of lymphocytes are programmed to epitopes?

Student: It is believed that billions of different epitopes may exist. 7 ………

Examiner: Can a single epitope initiate an immune response?

Student: Single epitopes are non-immunogenic. That is why for an immune response to occur the recognizing molecules must be cross-linked. 8 …...