Figure 4
Evolution of humoral immune responses over time. Means (± standard deviation) of swIAV-specific antibodies (Ab) titers in the six groups, obtained by virus neutralization test (A and C) or by hemagglutination inhibition test (B and D), using either 272/20-H1avN1 (A and B) or 154/20-H1avN2 (C and D) as an antigen. The dates of the first 272/20-H1avN1 (HA clade 1C.2.1) or 154/20-H1avN2 (HA clade 1C.2.4) challenge and of the second 154/20-H1avN2 challenge are indicated by a black and a green arrow, respectively. Significant differences between groups are indicated by different letters. H1N1 and H1N1 VACC: groups challenged at D0 with the 272/20-H1avN1 strain (HA clade 1C.2.1). H1N2 and H1N2 VACC: groups challenged at D0 with the 154/20-H1avN2 strain (HA clade 1C.2.4).