nerating antibodies with in ased binding affinities is called affinity Class switching or class switching is a biological p o afte classes of antibody(IgA,IgE,or IgG).The different classes of antibody,and thus effector functions,are defined by the constant ( ,家 he immunoglob eB binding regions.Each isotype is adapte therefore,after activation,an antibody with an IgG.IgA,or IgE effector function might be required to effectively eliminate an antigen.Cl 国g“ Only the constant region of the antibody heavy chain ch during class switching:the variable regions,and therefore antiger Mechanism of cla witch r tha specificity.rema in unchanged.Thus the progeny of a single Bcell n produce ant he same antgen.bu antigenic challenge.Class switching cytokines are present in the B cell environment.44 mre in tho he chain gene locus by a mechanism called class switch re mbination(CSR) This mechanism relies on conserved nucleotide motifs,called switch (S)regions,found in DNA ups am of ech t n (an)Thed isoken byhe city ofof enzymes at two selected s The variable domain exon is rejoined through a process called non- EJ)to the desir Affinity designations A group of antibodies can be called monovalent(or specific)if they have affinity for the same epitopeor 一 microorganism mentor unspecific)if they have amfnity or microorganisms. Intravenous e noted,consists of polyvalent IgG.In contrast,monoclonal antibodies are mo me epitope Asymmetrical antibodies which are also asymmetrical and antibodie allow for greater flexibility and new of th in antibodies The "knobs"nart is engineered by replacing a smallamino acid with a larger one.It fits into the "hole",which is engineered by replacing a large amino acid with a smaller one.What connects the"knobs"to the "holes"are the d ulfide bonds between e chain.The "knobs-into-holes shape facilitate es antibody d tide.The necte s rich i oe it r ,and serine/which gives it specificity.Two different scFfragments can be comected more together,via a hinge region,to the constant domain of the heavy chain or the constant domain of the light