Enlist any two factors responsible for antigenecity.
Answers
Antigen is a substances usually protein in nature and sometimes polysaccharide, that generates a specific immune response and induces the formation of a specific antibody or specially sensitized T cells or both.
Although all antigens are recognized by specific lymphocytes or by antibodies, only some antigens are capable of activating lymphocytes. Molecules that stimulate immune responses are called Immunogens.
Epitope is immunologically active regions of an immunogen (or antigen) that binds to antigen-specific membrane receptors on lymphocytes or to secreted antibodies. It is also called antigenic determinants.
Autoantigens, for example, are a person’s own self antigens. Examples: Thyroglobulin, DNA, Corneal tissue, etc.
Alloantigens are antigens found in different members of the same species (the red blood cell antigens A and B are examples).
Heterophile antigens are identical antigens found in the cells of different species. Examples: Forrssman antigen, Cross-reacting microbial antigens, etc.
Adjuvants are substances that are non-immunogenic alone but enhance the immunogenicity of any added immunogen.