Figure 3. Human B-cells detecting HAC1. Human peripheral blood mononuclear cells (PBMCs) isolated 7 d post vaccination were analyzed by ELISPOT to identify antibody secreting cells (ASCs) recognizing the HAC1 antigen or the vaccine antigen. For each sample the number of B-cells secreting specific antibodies of the IgG, IgA and IgM classes were quantified in 100,000 PBMCs. Each symbol represents one individual volunteer. Lines indicate the mean ± standard error of the mean (SEM). n = 15