Segura M A, Cléroux P, Gottschalk M
Groupe de Recherche sur les Maladies Infectieuses du Porc, Faculté de Médecine Vétérinaire, Université de Montréal, Qué, Canada.
FEMS Immunol Med Microbiol. 1998 Jul;21(3):189-95. doi: 10.1111/j.1574-695X.1998.tb01165.x.
Streptococcus suis type 2 and group B Streptococcus type III (GBS) are important encapsulated bacterial species causing meningitis. In the present study we compared quantitatively the uptake and intracellular survival of S. suis type 2 and GBS type III with murine macrophages in non-opsonic conditions. The role of the capsule of both pathogens was also studied using previously obtained unencapsulated isogenic mutants. Encapsulated S. suis wild-type strain was practically not phagocytosed, while the unencapsulated mutant was easily ingested by macrophages. On the other hand, the well encapsulated GBS strain and its unencapsulated mutant were both phagocytosed in large numbers. Even if S. suis unencapsulated mutant showed a higher uptake rate than the parental strain, this value was always markedly lower than the numbers of ingested GBS strains. In addition, the intracellular survival of encapsulated and unencapsulated GBS strains was significantly higher than that of S. suis strains. These results suggest that interactions between GBS type III and S. suis type 2 with murine macrophages as well as the role of the capsule as an antiphagocytic factor are different for the two bacterial pathogens.
2型猪链球菌和III型B族链球菌（GBS）是引起脑膜炎的重要荚膜细菌种类。在本研究中，我们在非调理素存在的条件下，对2型猪链球菌和III型GBS与小鼠巨噬细胞的摄取和细胞内存活情况进行了定量比较。还使用先前获得的无荚膜同基因突变体研究了两种病原体荚膜的作用。有荚膜的猪链球菌野生型菌株几乎不被吞噬，而无荚膜突变体则很容易被巨噬细胞摄取。另一方面，高度有荚膜的GBS菌株及其无荚膜突变体均被大量吞噬。即使猪链球菌无荚膜突变体的摄取率高于亲本菌株，该值也始终明显低于摄取的GBS菌株数量。此外，有荚膜和无荚膜GBS菌株的细胞内存活率明显高于猪链球菌菌株。这些结果表明，III型GBS和2型猪链球菌与小鼠巨噬细胞之间的相互作用以及荚膜作为抗吞噬因子的作用在两种细菌病原体中有所不同。
