ROLE OF NATURAL-KILLER-CELLS IN RESISTANCE TO CRYPTOCOCCUS-NEOFORMANS INFECTIONS IN MICE

  • 1 August 1987
    • journal article
    • research article
    • Vol. 128  (2) , 354-361
Abstract
Previous studies have suggested a possible role for natural kiler (NK) cells in resistance to some fungal infections, including Cryptococcus neoformans infections. The role of NK cells in early clearance of C. neoformans from tissues and in long-term survival was studied in mice following intravenous inoculations of the organism. Mice treated with anti-asialo GM1 antiserum to temporaily reduce NK activity demonstrated an increase in colony-forming units (CFU) of C. neoformans in the lung 24 hours after an intravenous inoculation of the organism. CFU in liver, spleen, kidney, and brain were not different in anti-asialo GM1 antiserum-treated versus control mice. An NK-specific reagent, anti-NK 1.1 monoclonal antibody, was used to deplete mice of NK cells in vivo for at least 14 days without affecting other natural defenses. The number of C. neoformans retained in the lungs 24 hours after inoculation of the organism was significantly greater in NK cell-depleted mice than in controls, although CFU in other organs were unaffected. Following the intravenous inoculation of C. neoformans, the survival of anti-NK 1.1-treated mice was not different from control mice. The effect of NK cell activity on resistance to C. neoformans was also determined after an intratracheal inoculation of the organism. Mice pretreated with anti-NK 1.1 demonstrated no increases in CFU in the lungs, spleen, or brain as compared with controls. These data indicate that NK cells can play a role in vivo in early resistance against C. neoformans if the organism is delivered via the intravenous route. However, NK cells do not play a role in either determining survival after an intravenous inoculation nor in resistance during an infection acquired via the respiratory tract.