<prompt> All of the following statements about carbohydrateantigen are true except aEURIt has lower immunogenicityMemory response is seenCause polyclonal B cell stimulationDoes not require stimulation by T cells  <response>: Memory response is seen Antigen Antigen is a substance that stimulates the production of antibody, when introduced into the body. Type of antigen A. Based on chemical nature - Based on chemical nature, antigens can be : - i Proteins ii Polysaccharide Carbohydrates iii Lipids iv Nucleic acids - Proteins are most immunogenic, while lipids nucleic acids are least immunogenic. - Polysaccharides carbohydrates are less immunogenic than protein antigens, but are more antigenic than lipids nucleic acids. B. Based on immune response - On the basis of immune response, antigens can be divided into : - i T-cell dependent antigens ii T-cell in dependent antigens i T-cell dependent antigens Most of the protein antigens are T-cell dependent. Their immune response is dependent on T-cell activation. After exposure, these antigens are presented to T-cells helper T-cells by antigen presenting cells. These primed T-cells then secret cytokines that induce B-cells to produce antibody against that paicular antigen. T-cell dependent reaction has memory response, i.e., subsequent exposure to same antigen result in :? a A more rapid production of antibodies b Produced in greater amounts c Produced for a longer period of time. T-cell independent antigens carbohydrate Polysaccharide antigens are T- cell independent. Their immune response does not require activation of T-cells. These antigens directly stimulate B-cells without processing by antigen presenting cells. There is no memory response Protein antigen Carbohydrate antigen More immunogenic Less immunogenic T-cell dependent T-cell independent No tolerence Immunological tolerance occurs Induce Production of all type of antibodies Induce production of IgM and IgG only Memory response is seen No memory response Require processing by antigen presenting cells. Do not require processing Quickly metabolized Slowly metabolized 