Figure 4.

Natural antiviral Ig is derived from B-1 cells, acquired antiviral Ig from B-2 cells. Sera of allotype chimeras (n = 13) and control mice (for Igh^a, BALB/c mice, n = 12; for Igh^b, C.B-17 mice, n = 11) were tested before and seven of the chimeras and all controls were also tested at day 7 after influenza virus infection for levels of influenza virus-specific Igh^a and Igh^b, IgM, and IgG2a. Units anti-influenza Ig were calculated in relation to standard hyperimmune sera. Data are shown as interquartile boxes; disconnected bars above and below the boxes indicate the 90th and 10th percentiles. ■, Data from individual mice. n.s., not significant. In chimeras, Igh^a is PerC donor-derived and therefore produced by B-1 cells.