T cell-dependent chronic neutrophilia during mycobacterial infections

Euthymic (nu/+) C57BL/6 mice intraperitoneally inoculated with 2.5 x 10(6) colony-forming units (CFU) of Mycobacterium avium developed a chronic peritoneal neutrophilic granulocytosis during the 30 days of infection studied; in contrast, congenitally athymic nude (nu/nu) mice of C57BL/6 background did not show such persistent neutrophil influx. The acute phase of peritoneal infection, characterized by an extensive accumulation of neutrophils peaking at 6 to 12 h post-inoculation, was similar in euthymic and athymic mice. Subcutaneous vaccination of C57BL/6 mice with BCG enhanced the peritoneal influx of granulocytes after the i.p. inoculation of 2.5 x 10(60 CFU of M. avium. Finally, spleen cells from M. avium-infected mice pulsed in vitro with mycobacterial antigen induced a higher neutrophil accumulation after inoculation into the peritoneal cavity of naive recipient mice than unpulsed spleen cells or spleen cells from noninfected mice. These data indicate that the immune system is involved in the regulation of the chronic neutrophil influx during mycobacterial infection.