Fig. 3.

Immune responses in rats after Tetanus Toxoid (TT) or PPS vaccination. Rats were intravenously vaccinated with either TT (Tetavax®) or PPS (Pneumovax ®) and blood was sampled at different time points after vaccination. A simultaneous, rapid IgM (▪) and IgG (d) response was observed after PPS vaccination, which declined to almost prevaccination values at day 24. Rats vaccinated with TT showed a late induction of only IgG antibodies (▴). IgM antibodies after TT vaccination were hardly detected. Values represent the average of 6–9 rats. Antibody titres are depicted in U/ml.