Practice question

Polyclonal antibody preparations heterogeneous mixture immunoglobulin molecules diverse B lymphocyte clones responding complex immunogen multiple antigenic determinants repetitive epitopes. Each naive B cell generates unique BCR random recombination RAG-mediated VDJ joining heavy chain variable diversity joining segments VJ joining light chain kappa lambda diversified junctional addition non-templated nucleotides TdT and somatic hypermutation germinal centers introducing point mutations rate 10^-3 per base division selecting higher affinity via follicular dendritic cell presentation. Immunization whole bacteria S. aureus viral glycoprotein influenza hemagglutinin toxoid tetanus toxoid containing repetitive carbohydrates conformational proteins activates numerous clones secreting IgG subclasses IgG1 IgG2 affinities 10^-6 to 10^-11 molar avidities multivalency. Serum contains antibodies recognizing linear peptide epitopes 8-12 residues discontinuous conformational surfaces formed distant residues folded together carbohydrate moieties neoepitopes formaldehyde treatment. Polyepitopic recognition enhances lattice formation C1q classical complement activation improving pathogen agglutination opsonization phagocytosis although batch variability cross-reactivity homologous antigens limited reproducibility complicate standardization compared monoclonal reagents uniform specificity.