Table 1.

Lysosomal hydrolase activities in lysates of bone marrow macrophages (Mφ) stimulated with lipopolysaccharide (LPS)

	Wild-type mean ± SEM (n)	TRAP-deficient mean ± SEM (n)
Tartrate-resistant acid phosphatase	0·408 ± 0·026 (4)	Not detectable (5)
Tartrate-sensitive acid phosphatase	0·006 ± 0·0026 (5)	0·186 ± 0·007* (9)
N-acetyl  βd-glucosaminidase	0·86 ± 0·11 (5)	1·32 ± 0·16 (9)
β-Glucuronidase	0·221 ± 0·018 (5)	0·221 ± 0·008 (7)

Resident bone marrow Mφ were isolated from wild-type and tartrate-resistant acid phosphatase (TRAP)-deficient mice and incubated with LPS (1 µg/ml) for 48 hr. Supernatants were removed, Triton-X-100 (0·5%) was added to the cells and lysates obtained by freeze–thaw cycles. TRAP and tartrate-sensitive acid phosphatase activities were measured by the hydrolysis of nitrophenylphosphate in the presence and absence of tartrate (100 mm), respectively. Glucosamine was measured by the hydrolysis of nitrophenylglucosaminide. These results are expressed as µmol of substrate hydrolysed/min/10⁶ cells. Acid β-glucuronidase was determined by the hydrolysis of phenolphthalein glucuronide, as described in the Materials and Methods, and is expressed as µmol of substrate hydrolysed/hr/10⁶ cells. Results are representative of three separate experiments.

^*P < 0·01, Student's t-test. TRAP and tartrate-resistant acid phosphatase only were measured in peritoneal Mφ, with similar findings.