antibodies that can actually enhance infection, referred to as antibody-dependent

enhancement (ADE). This has been observed for certain viral infections and occurs

when the specificity, affinity or titer is too low to be neutralizing and as shown in

Figure 3.15, the Fc portion of the antibody binds to cell surface receptors on a target

FIGURE 3.15 Antibody-dependent enhancement. (a) Virus bound by neutralizing anti-

bodies cannot infect cell. (b) Once bound to a virus, the Fc domain of non-neutralizing

antibodies can bind to cell surface Fc receptors thus facilitating the entry of virus into the

cell. (c) resulting in an inflamatory response.

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Bioprocessing of Viral Vaccines