Stimulation of human T lymphocytes obtained from Toxoplasma gondii-seronegative persons by proteins derived from T. gondii.
Toxoplasma gondii antigens are superantigens in mice. To investigate a superantigen effect in humans, lymphocytes from T. gondii-seronegative subjects were studied for proliferation to T. gondii antigens (TA). Marked cellular proliferation, predominantly of CD4+ lymphocytes, was apparent. TA elicited expansions of Vbeta-bearing lymphocytes in all subjects, but different Vbeta-bearing lymphocytes were expanded in different subjects in both CD4+ and CD8+ subpopulations. Cord blood cells also proliferated to TA. Previously fixed antigen-presenting cells were unable to present TA. Thus, T. gondii appears to produce a molecule(s) that induces polyclonal activation of human T cells and requires antigen processing to mediate this effect. That T. gondii does not appear to behave as a superantigen in humans is important in understanding the pathogenesis of T. gondii infection in immunocompromised hosts and in the design of anti-T. gondii vaccines.
Purner
M B
MB
Division of Infectious Disease, VA Medical Center, University of Colorado Health Sciences Center, Denver, USA.
Berens
R L
RL
Tomavo
S
S
Lecordier
L
L
Cesbron-Delauw
M F
MF
Kotzin
B L
BL
Curiel
T J
TJ
D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D000953:Antigens, Protozoan / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D005312:Fetal Blood / Q000166:cytology / Q000276:immunology; D006801:Humans; D008213:Lymphocyte Activation; D016693:Receptors, Antigen, T-Cell, alpha-beta; D012698:Serologic Tests; D018089:Superantigens / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D014122:Toxoplasma / Q000276:immunology*
D000953:Antigens, Protozoan; D016693:Receptors, Antigen, T-Cell, alpha-beta; D018089:Superantigens