Effect of the injection of an extract of Ascaris suum on macrophage activation during the early phase of Mycobacterium bovis BCG infection in C57Bl/6mice

Injection of an Ascaris suum extract (Asc) affects both the humoral and cel lular immune responses to unrelated antigens when it is coadministered with these antigens. In the present study we evaluated the effect of Asc on mac rophage activation in the early phase of Mycobacterium bovis BCG (Pasteur s train TMCC 1173) infection in C57B1/6 mice. C57B1/6 mice were injected intr aperitoneally tip) with 0.1 mg BCG (BCG group) or BCG plus 1 mg Asc (BCG Asc group). The peritoneal exudates were obtained at 2, 7 and 14 days after infection. The numbers of IFN-gamma-secreting cells were assessed by the E LISPOT assay. Nitric oxide (NO) production was measured by the Griess metho d and by the evaluation of NADPH diaphorase activity in the peritoneal exud ates. The administration of Asc extract increased NADPH diaphorase activity (2 days: control = 0, BCG = 7%, BCG + Asc = 13%, and Asc = 4%; 7 days: con trol = 4, BCG = 13%, BCG + Asc = 21%, and Asc = 4.5%) and TNF-alpha levels (mean +/- SD; 2 days: control = 0, BCG = 169 +/- 13, BCG + Asc = 202 +/- 37 , and Asc = 0; 7 days: control = 0, BCG = 545 +/- 15.5, BCG + Asc = 2206 +/ - 160.6, and Asc = 126 +/- 26; 14 days: control = 10 +/- 1.45, BCG = 9 +/- 1.15, BCG + Asc = 126 +/- 18, and Asc = 880 +/- 47.67 pg/ml) in the early p hase of BCG infection. Low levels of NO production were detected at 2 and 7 days after BCG infection, increasing at 14 days (mean +/- SD; 2 days: cont rol = 0, BCG = 3.7 +/- 1.59, BCG + Asc = 0.82 +/- 0.005, Asc = 0.48 +/- 0.3 3; 7 days: control = 0, BCG = 2.78 +/- 1.54, BCG + Ase = 3.07 +/- 1.05, Asc = 0; 14 days: control = 0, BCG = 9.05 +/- 053, BCG + Asc = 9.61 +/- 0.81, Asc = 10.5 +/- 0.2 (2 x 10(6)) cells/ml). Furthermore, we also observed tha t Ase co-injection induced a decrease of BCG-colony forming units (CFU) in the spleens of BCG-infected mice during the first week of infection (mean /- SD; 2 days: BCG = 1.13 +/-. 0.07 and BCG + Asc = 0.798 +/- 0.305; 7 days : BCG = 1.375 +/- 0.194 and BCG + Asc = 0.548 +/- 0.0226; 14 days: BCG = 0. 473 +/- 0.184 and BCG + Asc = 0.675 +/- 0.065 (x 10(2)) CFU), The present d ata suggest that Asc induces the enhancement of the immune response in the early phase of BCG infection.