A
suspension of heat-killed Mycobacterium tuberculosis in
liquid paraffin has been reported to induce foot swelling accompanied by new bone formation in Buffalo (BUF) rats, which are low responders to the induction of
adjuvant arthritis. In the present study, we found that
wax D, a mycobacterial cell wall
peptidoglycan fragment-
arabinogalactan-
mycolic acid complex, was an effective component of this bacterium for the induction of
osteomyelitis accompanied by reactive bone formation in BUF rats. Chronic
inflammation was produced in BUF rats by a single
subcutaneous injection of
wax D suspended in
liquid paraffin. Other Mycobacterium species and Gordona bronchialis were also capable of inducing this reaction. Other bacterial cells including the
acid-fast bacteria Nocardia and Rhodococcus, purified cell walls and peptidoglycans from Lactobacillus plantarum, wax C,
cord factor,
arabinogalactan and
mycolic acid prepared from M.
tuberculosis were inactive in this respect. In addition, when
wax D was administered as a water-in-oil
emulsion (Freund's type adjuvant), bone formation scarcely occurred in BUF rats. In Fisher (F344) and Wistar rats, both of which are responder strains to
adjuvant arthritis,
wax D in
liquid paraffin did not induce bone formation.