Figure 6
Pre-existing immunity. This figure uses the same layout as Fig. 2. Here, the proportion of mature memory cells at the start of the infection has been increased, to simulate the scenario that immunological memory may have been instantiated by exposure to related viruses in the past. Note the rapid increase in the IgG response, in contrast to the early IgM response we saw in Fig. 2. Like in Fig. 5, the virus is suppressed and never reaches as high a viral load as in Fig. 2. However, here we see a sustained increase in serum immunoglobulin in the latent (upper left) and measurable (middle right) antibody response plots. This pattern of response might be associated with a very mild illness, not prompting testing for the virus (or possibly even an undetectable viral load on being tested) but would be associated with positive serological tests later on.
