Porcine salivary agglutinins (pSAGs) aggregate
serotype 2 (S2) and serotype 9 (S9). Evaluation of the fluid phase aggregation of the wild-type S. suis S2 and S9 strains in the absence (−) or presence (+) of pSAGs. Aggregation in the absence of pSAGs reflects self-aggregation only. Data represent the mean ± SEM from at least three independent experiments. *(p < 0.05) and **(p < 0.01) indicate a significant difference of S. suis S2 or S9 aggregation in the absence and presence of pSAGs.