eng Oriental Scientific Publishing Company Biomedical and Pharmacology Journal 0974-6242 2015-10-25 8 October Spl Edition 249 252 10.13005/bpj/685 3774 article Raadha Ragavendran 1 V. Ramya 2 Preethe Paddmanabhan 3 Tutor, Department of Periodontics, Tagore Dental College and Hospital, Rathinamangalam, Chennai Reader, Department of Periodontics, Sree Balaji Dental College and Hospital, Bharath University, Chennai-600100 Senior Lecturer, Department of Periodontics, Sree Balaji Dental College and Hospital, Bharath University, Chennai-600100 Strong evidence is available on the role of Aggregatibacter actinomycetemcomitans (A.a) as the causative agent of localised juvenile periodontitis (LJP), a disease characterised by rapid destruction of the tooth-supporting tissues. This organism possesses a large number of virulence factors with a wide range of activities which enable it to colonise the oral cavity, invade periodontal tissues, evade host defences, initiate connective tissue destruction and interfere with tissue repair. Adhesion to epithelial and tooth surfaces is dependent on the presence of surface proteins and structures such as microvesicles and fimbriae. Invasion has been demonstrated in vivo and in vitro. The organism has a number of means of evading host defences, which include: (i) production of leukotoxin; (ii) producing immunosuppressive factors; (iv) secreting proteases capable of cleaving IgG; and (v) producing Fc-binding. https://biomedpharmajournal.org/vol8octoberspledition/aggregatibacter-actinomycetemcomitans-its-role-in-periodontitis/ Periodontitis Leukotoxin Lipopolysaccharide