8536d_ch03_057-075 8/6/02 10:28 AM Page 60 mac79 Mac 79: 45_Bw Glasby et al. Immunology 5e 60 PART I Generation of B-Cell and T-Cell Response BlE 3-2 Specificity of an antibody against a complex lipid Structure CHa NH 00.0 HO Leukotriene D4 人 OH The reactivity of the antibody with the immunizing antigen leukotriene C4 is assigned a value of 100 in arbitrary units. SUSCEPTIBILITY TO ANTIGEN PROCESSING The Biological System Contributes AND PRESENTATION to Immunogenic The development of both humoral and cell-mediated im mune responses requires interaction of T cells with antigen Even if a macromolecule has the properties that contribute to that has been processed and presented together with MHC immunogenicity, its ability to induce an immune response molecules. Large, insoluble macromolecules generally are vill depend on certain properties of the biological system more immunogenic than small, soluble ones because the that the antigen encounters. These properties include the larger molecules are more readily phagocytosed and genotype of the recipient, the dose and route of antigen ad- presented with MHC molecules are poor immunogens. This adjuvants, that increase immune response, bstances,called processed Macromolecules that cannot be degraded and an be illustrated with polymers of D-amino acids, which are stereoisomers of the naturally occurring L-amino acids. Be GENOTYPE OF THE RECIPIENT ANIMAL cause the degradative enzymes within antigen-presenting The genetic constitution(genotype)of an immunized an cells can degrade only proteins containing L-amino is, mal influences the type of immune response the animal polymers of D-amino acids cannot be processed and thus are manifests, as well as the degree of the response. For example, Poor Immunogens Hugh McDevitt showed that two different inbred strains ofSUSCEPTIBILITY TO ANTIGEN PROCESSING AND PRESENTATION The development of both humoral and cell-mediated im￾mune responses requires interaction of T cells with antigen that has been processed and presented together with MHC molecules. Large, insoluble macromolecules generally are more immunogenic than small, soluble ones because the larger molecules are more readily phagocytosed and processed. Macromolecules that cannot be degraded and presented with MHC molecules are poor immunogens. This can be illustrated with polymers of D-amino acids, which are stereoisomers of the naturally occurring L-amino acids. Be￾cause the degradative enzymes within antigen-presenting cells can degrade only proteins containing L-amino acids, polymers of D-amino acids cannot be processed and thus are poor immunogens. The Biological System Contributes to Immunogenicity Even if a macromolecule has the properties that contribute to immunogenicity, its ability to induce an immune response will depend on certain properties of the biological system that the antigen encounters. These properties include the genotype of the recipient, the dose and route of antigen ad￾ministration, and the administration of substances, called adjuvants, that increase immune responses. GENOTYPE OF THE RECIPIENT ANIMAL The genetic constitution (genotype) of an immunized ani￾mal influences the type of immune response the animal manifests, as well as the degree of the response. For example, Hugh McDevitt showed that two different inbred strains of 60 PART II Generation of B-Cell and T-Cell Responses TABLE 3-2 Specificity of an antibody against a complex lipid Antibody reactivity* Lipid Structure (on scale of 1 to 100) Leukotriene C4 100.0 Leukotriene D4 5.0 Leukotriene E4 0.5 Prostaglandin D2 0.001 * The reactivity of the antibody with the immunizing antigen leukotriene C4 is assigned a value of 100 in arbitrary units. OH OH CH3 O S O NH2 OH OH OH O CH3 HO O † OH OH CH3 NH2 O S O HO O O O N H OH NH † OH OH CH3 O S O O N H OH H2N 8536d_ch03_057-075 8/6/02 10:28 AM Page 60 mac79 Mac 79:45_BW:Goldsby et al. / Immunology 5e: