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Reasons why DBA/2 mice are resistant to malarial infection: expansion of CD3 int B220 + γδ T cells with double‐negative CD4 – CD8 – phenotype in the liver
Author(s) -
Bakir Hanaa Y.,
TomiyamaMiyaji Chikako,
Watanabe Hisami,
Nagura Toru,
Kawamura Toshihiko,
Sekikawa Hiroho,
Abo Toru
Publication year - 2006
Publication title -
immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.297
H-Index - 133
eISSN - 1365-2567
pISSN - 0019-2805
DOI - 10.1111/j.1365-2567.2005.02273.x
Subject(s) - cd8 , biology , microbiology and biotechnology , plasmodium yoelii , immune system , cytotoxic t cell , antibody , t lymphocyte , cytokine , cd3 , immunology , in vitro , plasmodium falciparum , parasitemia , genetics , malaria
Summary DBA/2 (H‐2 d ) mice are known to be more resistant than C57BL/6 (B6, H‐2 b ) mice to the non‐lethal 17XNL strain of Plasmodium yoelii . This is a very strange phenomenon because the functions of conventional T cells, especially CD8 + T cells, are known to be somewhat lower in DBA/2 mice than in other strains of mice. We examined herein how immune responses differed between DBA/2 mice and B6 mice during malarial infection. DBA/2 mice and (DBA/2 × B6)F 1 (BDF 1 , H‐2 b/d ) mice were found to have milder parasitaemia and to recover more quickly from malarial infection than B6 mice. These DBA/2 and BDF 1 mice were also found to experience a marked expansion of interleukin (IL)‐2Rβ + CD3 int cells and γδ T cells in the liver, especially in the recovery phase. The expansion of unconventional T cells (i.e. B220 + T cells) was also marked in DBA/2 and BDF 1 mice. The majority of B220 + T cells were γδ T cells and these T cells were double‐negative CD4 − CD8 − . More importantly, the production of immunoglobulin M (IgM)‐type anti‐DNA autoantibody was also higher in DBA/2 and BDF 1 mice than in B6 mice. In conjunction with data on cytokine production, these results indicate that primitive T and B cells, namely autoreactive extrathymic T cells and autoantibody‐producing B cells, may be much more activated in DBA/2 mice and therefore resistant to the non‐lethal 17XNL strain of P. yoelii.