       Document 0830
 DOCN  M9550830
 TI    Inhibition of Plasmodium falciparum growth in vitro by CD4+ and CD8+ T
       cells from non-exposed donors.
 DT    9505
 AU    Fell AH; Currier J; Good MF; Molecular Immunology Laboratory, Queensland
       Institute of Medical; Research, Brisbane, Australia.
 SO    Parasite Immunol. 1994 Nov;16(11):579-86. Unique Identifier : AIDSLINE
       MED/95166575
 AB    T cells from most adult non-exposed donors, which express a memory
       phenotype (CD45RO+), can respond by proliferation to P. falciparum
       asexual stages in vitro. Such cells may have arisen from exposure to
       environmental organisms. To address the efficacy of such cells in
       eliminating parasites and investigate the mechanisms involved, we have
       used an in vitro assay where parasite growth can be precisely monitored
       in the presence of different cell preparations. Unfractionated
       peripheral blood mononuclear cells (PBMC) from both malaria-exposed and
       non-exposed donors inhibited parasite growth by up to 62% in a two day
       assay. Purified T cells in the presence of adherent cells had a similar
       effect, but purified T cells alone or adherent cells alone had minimal
       effect. Antigens released at the time of schizont rupture were maximally
       effective in stimulating interferon-gamma (IFN gamma) production.
       Neutralizing antibodies to IFN gamma showed a partial reduction of
       growth inhibition in some individuals tested suggesting that different
       mechanisms may be operative. Neutralizing antibody to TNF alpha had a
       partial effect in combination with anti-IFN gamma. Antibodies to IL-1
       and IL-4 had no effect. T cell fractionation experiments showed that
       while purified CD4+ T cells from some donors produced IFN gamma and
       inhibited parasite growth, purified CD8+ T cells could inhibit parasite
       growth to a greater extent without production of detectable IFN
       gamma.(ABSTRACT TRUNCATED AT 250 WORDS)
 DE    Adolescence  Adult  Aged  Animal  Antibodies/IMMUNOLOGY  Antigens,
       Protozoan  Blood Donors  Child  Clone Cells  Cytokines/IMMUNOLOGY
       CD4-Positive T-Lymphocytes/*IMMUNOLOGY  CD8-Positive
       T-Lymphocytes/*IMMUNOLOGY  Human  Immunity, Cellular  In Vitro
       Leukocytes, Mononuclear/IMMUNOLOGY  Malaria, Falciparum/IMMUNOLOGY
       Middle Age  Plasmodium falciparum/GROWTH & DEVELOPMENT/*IMMUNOLOGY
       Rabbits  Support, Non-U.S. Gov't  JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).

