Plasmodium falciparum apical membrane antigen 1 vaccine elicits multifunctional CD4 cytokine-producing and memory T cells.
The Plasmodium falciparum apical membrane antigen 1 (AMA1) is a leading vaccine candidate and was tested for safety and immunogenicity in human Phase I Clinical Trials. PBMC from vaccine recipients were analyzed by flow cytometric methods to determine the nature of T-cell responses and AMA1-reactive memory T cells. Both CD4 and CD8 T cells produced a number of cytokines following AMA1 re-stimulation, with IL-5-producing cells at the highest frequency, consistent with a Th2 bias. The relative frequency of multifunctional cells synthesizing Th1 cytokines IFN-gamma, IL-2 and TNF-alpha changed after each vaccination. Interestingly, median fluorescence intensity measurements revealed that cells producing more than one cytokine contributed greater quantities of each cytokine than cell populations that produced each of the cytokines alone. AMA1 vaccination also elicited the development of memory cell populations, and both central and effector memory T cells were identified concurrently after the AMA1 vaccination. The detailed profile of multifunctional T-cell responses to AMA1 presented here will advance our ability to assess the immunogenicity of human malarial vaccines.
Huaman
Maria Cecilia
MC
Laboratory of Malaria and Vector Research and Malaria Vaccine Development Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA. huamanc@niaid.nih.gov
Mullen
Gregory E D
GE
Long
Carole A
CA
Mahanty
Siddhartha
S
D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D000953:Antigens, Protozoan / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D006801:Humans; D007156:Immunologic Memory; D007371:Interferon-gamma / Q000276:immunology; D007376:Interleukin-2 / Q000276:immunology; D015848:Interleukin-5 / Q000276:immunology; D017780:Malaria Vaccines / Q000276:immunology*; D016778:Malaria, Falciparum / Q000517:prevention & control*; D008565:Membrane Proteins / Q000276:immunology*; D010963:Plasmodium falciparum / Q000276:immunology*; D015800:Protozoan Proteins / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology
D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D007376:Interleukin-2; D015848:Interleukin-5; D017780:Malaria Vaccines; D008565:Membrane Proteins; D015800:Protozoan Proteins; D014409:Tumor Necrosis Factor-alpha; C090077:apical membrane antigen I, Plasmodium; D007371:Interferon-gamma