Sandberg A L, Mudrick L L, Cisar J O, Brennan M J, Mergenhagen S E, Vatter A E
Infect Immun. 1986 Nov;54(2):472-6. doi: 10.1128/iai.54.2.472-476.1986.
Phagocytosis of Actinomyces viscosus T14V and A. naeslundii WVU45 by human polymorphonuclear leukocytes in the absence of antibody or complement was mediated by the lectin associated with the type 2 fimbriae of these bacteria. This effect was markedly enhanced by exogenous sialidase, an enzyme also secreted by these actinomyces. Since sialidase treatment of the bacteria did not result in increased phagocytosis, this enzyme presumably acts by unmasking receptors for the fimbrial lectin on phagocytic cells. The viability of A. viscosus T14V, which possesses type 1 and type 2 fimbriae (1+ 2+), and A. naeslundii WVU45, which possesses only type 2 fimbriae (2+), was decreased by at least 98% following incubation with polymorphonuclear leukocytes in the presence of sialidase. Entirely analogous findings were obtained with a 1- 2+ mutant of A. viscosus T14V. In contrast, the phagocytosis of 1+ 2- and 1- 2- mutants of A. viscosus T14V and a 2- mutant of A. naeslundii WVU45 was minimal or absent. Lactose and beta-methylgalactoside inhibited the destruction of the bacteria, whereas cellobiose and alpha-methylgalactoside were ineffective. Thus, the type 2 fimbriae of the oral actinomyces recognize galactose-containing receptors on polymorphonuclear leukocytes which have been exposed by the removal of sialic acid, an interaction that is followed by internalization and subsequent killing of the bacteria.
在没有抗体或补体的情况下，人类多形核白细胞对黏性放线菌T14V和内氏放线菌WVU45的吞噬作用是由与这些细菌2型菌毛相关的凝集素介导的。外源性唾液酸酶可显著增强这种作用，该酶也是这些放线菌分泌的。由于用唾液酸酶处理细菌并不会导致吞噬作用增强，因此推测这种酶的作用是通过暴露吞噬细胞上菌毛凝集素的受体来实现的。在唾液酸酶存在的情况下，与多形核白细胞孵育后，同时具有1型和2型菌毛（1+ 2+）的黏性放线菌T14V和仅具有2型菌毛（2+）的内氏放线菌WVU45的活力至少降低了98%。用黏性放线菌T14V的1- 2+突变体也得到了完全类似的结果。相比之下，黏性放线菌T14V的1+ 2-和1- 2-突变体以及内氏放线菌WVU45的2-突变体的吞噬作用极小或不存在。乳糖和β-甲基半乳糖苷可抑制细菌的破坏，而纤维二糖和α-甲基半乳糖苷则无效。因此，口腔放线菌的2型菌毛可识别多形核白细胞上含半乳糖的受体，这些受体因唾液酸的去除而暴露，随后发生相互作用，接着细菌被内化并被杀死。
