%0 Journal Article %A Klier, Christiane M. %A Kolenbrander, Paul E. %A Roble, Arlene G. %A Marco, Maria L. %A Cross, Sharon %A Handley, Pauline S. %T Identification of a 95 kDa putative adhesin from Actinomyces serovar WVA963 strain PK1259 that is distinct from type 2 fimbrial subunits %D 1997 %J Microbiology, %V 143 %N 3 %P 835-846 %@ 1465-2080 %R https://doi.org/10.1099/00221287-143-3-835 %K coaggregation %K oral actinomyces %K fimbriae %K adhesin %I Microbiology Society, %X The species Actinomyces serovar WVA963 is among the 20 bacteria most frequently isolated from human subgingival plaque. The interactions of this species with streptococci are inhibited by lactose, a function associated with type 2 fimbrial surface structures in Actinomyces naeslundii. Type 1 fimbriae mediate binding of cells to salivary proline-rich proteins. Specific polyclonal antisera against type 1 and type 2 fimbriae of A. naeslundii T14V revealed both types of fimbriae on Actinomyces serovar WVA963 strain PK1259. To investigate the role of type 2 fimbriae of strain PK1259 in Actinomyces-Streptococcus lactose-inhibitable coaggregations, spontaneous coaggregation-defective (Cog-) mutants that failed to coaggregate with streptococci were isolated; three were chosen for study. All three mutant strains synthesized type 1 fimbriae and a 59 kDa protein; mutant strains PK2415 and PK3092 synthesized type 2 fimbriae and a 57 kDa protein. In contrast, the Cog-strain PK2407 did not agglutinate with anti-type 2 antibodies or show the 57 kDa band, suggesting that the 57 kDa protein was the type 2 fimbrial subunit. Polyclonal antiserum raised against the Actinomyces serovar WVA963 strain PK2399, an antibiotic-resistant derivative of wild-type PK1259, blocked coaggregation between this strain and streptococci. Anti-PK2399 serum absorbed with mutant strain PK3092 bearing type 2 fimbriae retained its blocking ability. Surface sonicates of the parent and mutant strains were adsorbed to streptococcal cells and to lactose-agarose beads. Lactose eluates from both the streptococcal cells and the affinity beads were characterized by SDS-PAGE and corresponding immunoblots using anti-PK2399 serum absorbed with Cog-mutant PK3092. These blots revealed a 95 kDa putative adhesin in the parent strain PK2399 that was absent in the Cog-mutant strain PK3092. These results suggest the presence of a putative 95 kDa actinomyces adhesin distinct from the 57 kDa type 2 fimbrial subunit and that this adhesin mediates lactose-inhibitable coaggregation with streptococci. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-143-3-835