TY - JOUR
T1 - Perforin and gamma interferon are critical CD8+ T-cell-mediated responses in vaccine-induced immunity against Leishmania amazonensis infection
AU - Colmenares, María
AU - Kima, Peter E.
AU - Samoff, Erika
AU - Soong, Lynn
AU - McMahon-Pratt, Diane
PY - 2003/6/1
Y1 - 2003/6/1
N2 - Previous studies have demonstrated that protection against New World leishmaniasis caused by Leishmania amazonensis can be elicited by immunization with the developmentally regulated Leishmania amastigote antigen, P-8. In this study, several independent experimental approaches were employed to investigate the protective immunological mechanisms involved. T-cell subset depletion experiments clearly indicate that elicitation of CD8+ (as well as CD4+) effector responses is required for protection. Further, mice lacking β2-microglobulin (and hence deficient in major histocompatibility complex class I antigen presentation) were not able to control a challenge infection after vaccination, indicating an essential protective role for CD8+ T effector responses. Analysis of the events ongoing at the cutaneous site of infection indicated a changing cellular dynamic involved in protection. Early postinfection in protectively vaccinated mice, a predominance of CD8+ T cells, secreting gamma interferon (IFN-γ) and expressing perforin, was observed at the site of infection; subsequently, activated CD4+ T cells producing IFN-γ were primarily found. As protection correlated with the ratio of total IFN-γ-producing cells (CD4+ and CD8+ T cells) to macrophages found at the site of infection, a role for IFN-γ was evident; in addition, vaccination of IFN-γ-deficient mice failed to provide protection. To further assess the effector mechanisms that mediate protection, mice deficient in perforin synthesis were examined. Perforin-deficient mice vaccinated with the P-8 antigen were unable to control infection. Thus, the elicitation of CD8+ T cell effector mechanisms (perforin, IFN-γ) are clearly required in the protective immune response against L. amazonensis infection in vaccinated mice.
AB - Previous studies have demonstrated that protection against New World leishmaniasis caused by Leishmania amazonensis can be elicited by immunization with the developmentally regulated Leishmania amastigote antigen, P-8. In this study, several independent experimental approaches were employed to investigate the protective immunological mechanisms involved. T-cell subset depletion experiments clearly indicate that elicitation of CD8+ (as well as CD4+) effector responses is required for protection. Further, mice lacking β2-microglobulin (and hence deficient in major histocompatibility complex class I antigen presentation) were not able to control a challenge infection after vaccination, indicating an essential protective role for CD8+ T effector responses. Analysis of the events ongoing at the cutaneous site of infection indicated a changing cellular dynamic involved in protection. Early postinfection in protectively vaccinated mice, a predominance of CD8+ T cells, secreting gamma interferon (IFN-γ) and expressing perforin, was observed at the site of infection; subsequently, activated CD4+ T cells producing IFN-γ were primarily found. As protection correlated with the ratio of total IFN-γ-producing cells (CD4+ and CD8+ T cells) to macrophages found at the site of infection, a role for IFN-γ was evident; in addition, vaccination of IFN-γ-deficient mice failed to provide protection. To further assess the effector mechanisms that mediate protection, mice deficient in perforin synthesis were examined. Perforin-deficient mice vaccinated with the P-8 antigen were unable to control infection. Thus, the elicitation of CD8+ T cell effector mechanisms (perforin, IFN-γ) are clearly required in the protective immune response against L. amazonensis infection in vaccinated mice.
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U2 - 10.1128/IAI.71.6.3172-3182.2003
DO - 10.1128/IAI.71.6.3172-3182.2003
M3 - Article
C2 - 12761096
AN - SCOPUS:0037767300
SN - 0019-9567
VL - 71
SP - 3172
EP - 3182
JO - Infection and immunity
JF - Infection and immunity
IS - 6
ER -