A

Actinobacillus (actually Aggregatibacter) actinomycetemcomitans is consistently isolated from lesions of localized juvenile/aggressive periodontitis, elicits high serum antibody levels in affected patients, and disease resolution follows its elimination, making it the principal etiologic species; Prevotella intermedia and Mycoplasma are not primary agents [Zambon, 1985, PMID 3882766].