“…Whereas protein model antigens adsorbed in alum usually induce short-lived GCs that collapse within the first month after immunization, certain synthetic vaccines, viral infections or the gut microbiota can induce GCs that remain active for much longer periods, if not indefinitely (Adachi et al, 2015; Bachmann et al, 1996; Kasturi et al, 2011; Sutherland et al, 2016). Prolonged GC reactions may allow B cells to reach a higher degree of affinity maturation (Klein et al, 2013; Pappas et al, 2014) and may represent a means to cope with the antigenic drift associated with chronic viral infection (Bonsignori et al, 2016; Liao et al, 2013).…”