TY - JOUR
T1 - Cytotoxic CD4+ T cells use granulysin to kill Cryptococcus neoformans, and activation of this pathway is defective in HIV patients
AU - Chun, Fu Zheng
AU - Ling, Ling Ma
AU - Jones, Gareth J.
AU - Gill, M. John
AU - Krensky, Alan M.
AU - Kubes, Paul
AU - Mody, Christopher H.
PY - 2007/3/1
Y1 - 2007/3/1
N2 - An important mechanism of host defense to Cryptococcus neoformans involves the direct microbicidal activity of lymphocytes. The importance of CD4 + T cells is illustrated by the incidence of this infection in the acquired immunodeficiency syndrome (AIDS) patients; however, the relative activity of microbicidal CD4+ T cells compared with CD8+ T cells and natural killer (NK) cells has not been established. Further, although NK cells and CD8+ T cells use perforin or granulysin, respectively, to kill C neoformans, the effector molecule used by CD4+ T cells is not known. Experiments demonstrated that IL-2-activated peripheral blood lymphocytes from healthy adults acquire anticryptococcal activity, and surprisingly, that CD4+ T cells had the most profound effect on this activity. Using SrCl2-induced degranulation and siRNA knockdown, granulysin was shown to be the effector molecule. Although activation by anti-CD3 + IL-2 resulted in the additional expression of perforin, this did not improve the anticryptococcal activity. Cryptococcal killing by CD4+ T cells was defective in human immunodeficiency virus (HIV)-infected patients due to dysregulated granulysin and perforin production in response to IL-2 or anti-CD3 + IL-2. In conclusion, CD4+ T cells are the major subset of cells responsible for killing C neoformans in peripheral blood. These cells use granulysin as the effector molecule, and priming is dysregulated in HIV-infected patients, which results in defective microbicidal activity.
AB - An important mechanism of host defense to Cryptococcus neoformans involves the direct microbicidal activity of lymphocytes. The importance of CD4 + T cells is illustrated by the incidence of this infection in the acquired immunodeficiency syndrome (AIDS) patients; however, the relative activity of microbicidal CD4+ T cells compared with CD8+ T cells and natural killer (NK) cells has not been established. Further, although NK cells and CD8+ T cells use perforin or granulysin, respectively, to kill C neoformans, the effector molecule used by CD4+ T cells is not known. Experiments demonstrated that IL-2-activated peripheral blood lymphocytes from healthy adults acquire anticryptococcal activity, and surprisingly, that CD4+ T cells had the most profound effect on this activity. Using SrCl2-induced degranulation and siRNA knockdown, granulysin was shown to be the effector molecule. Although activation by anti-CD3 + IL-2 resulted in the additional expression of perforin, this did not improve the anticryptococcal activity. Cryptococcal killing by CD4+ T cells was defective in human immunodeficiency virus (HIV)-infected patients due to dysregulated granulysin and perforin production in response to IL-2 or anti-CD3 + IL-2. In conclusion, CD4+ T cells are the major subset of cells responsible for killing C neoformans in peripheral blood. These cells use granulysin as the effector molecule, and priming is dysregulated in HIV-infected patients, which results in defective microbicidal activity.
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U2 - 10.1182/blood-2006-03-009720
DO - 10.1182/blood-2006-03-009720
M3 - Article
C2 - 17038537
AN - SCOPUS:33847379511
SN - 0006-4971
VL - 109
SP - 2049
EP - 2057
JO - Blood
JF - Blood
IS - 5
ER -