Are differences in timing due to germ-line immunoglobulin sequences?
How then could the intrinsic properties of the viral surface glycoprotein account for the timing of neutralizing antibody responses? In some cases, highly glycosylated proteins, such as the HIV or simian immunodeficiency virus (SIV) envelope glycoproteins, can only induce low titers of neutralizing antibodies. Removal of glycosylation sites of the SIV glycoprotein allows the induction of antibodies with increased neutralizing activity (13). The high levels of glycosylation, however, may interfere with the ability of the virus to induce high titers of neutralizing antibodies, but do not affect the timing of neutralizing antibody production. The answer to the question posed by Pinschewer and colleagues may have more to do with how the antibody response evolves. Neutralizing antibodies tend to be of high affinity to virion surface proteins in order to compete with virion binding to host receptors (14). Most antibodies reach high affinity as a result of affinity maturation, a CD4+ T cell–d
