Nicotiana benthamiana and Arabidopsis thaliana heat shock protein 90 induce mouse B cells proliferation.

CORIGLIANO M; LAGUIA BECHER M; ANGEL SO; CLEMENTE M

Guadalajara

Encuentro; VII Encuentro Latinoamericano y del Caribe sobre Biotecnología Agropecuaria; 2010

REDBIO MEXICO

Under the hypothesis that the immunological properties of Hsp90 observed in human, bacteria and parasites are also present in their plant orthologous, we evaluated the ability of the recombinant A. thaliana and N. benthamiana Hsp90s (AtHsp90 and Nb Hsp90, respectively) to induce proliferation of naive BALB/c mice splenocytes in vitro. AtHsp81.2 and NbHsp90.2 full length sequences were cloned, over expressed and purified from E.coli cells. Once confirmed the identity by mass spectrometric analysis, the stimulation ability of plant rHsp90 in spleen cells from BALB/c mice was examined. As control, Leishmania infantum Hsp83 (LiHsp83) and Toxoplama gondii Hsp28 (TgHsp28) was tested. Plant rHsp90 induced prominent proliferative responses of spleen cell like LiHsp83, whereas TgHsp28 did not induce this proliferative response. Therefore, this proliferative response of spleen cells was specifically induced by plant rHsp90 and LiHsp83. Also, the proliferation capacity of LPS and ConA was evaluated. As expected, both LPS and ConA was able to induce proliferation responses of spleen cells. However, the proliferation capacity of LPS was abolished by the polymyxin-B (PX) treatment suggesting that the proliferation capacity of the AtHsp81.2 and NbHsp90.2 preparations must be attributed to the proteins and not to LPS contamination. Flow cytometry analysis of the immunoestimulated cells revealed that stimulation of splenocytes with AtHsp81.2 and NbHsp90.2 promoted an marked proliferation of the CD19 B cells, while CD3 T cells did not respond to plant rHsp90.Thus, the results suggested that the main spleen cell population proliferating in response to plant rHsp90s is constituted by B lymphocytes not T cells. This work shows the first evidence that spleen cell proliferation can be stimulated by non-pathogen-derived Hsp90.