Chaperonin 10 of Mycobacterium tuberculosis induces a protective immune response to foot-and-mouth disease virus

Chaperonin 10 of M. tuberculosis conferred partial or total protection agai nst generalized foot-and-mouth disease (FMD) in guinea-pigs challenged with O-1 Lausanne FMD virus. Chaperonin 10-immunized animals mounted an antibod y response to the protein, one epitope of which was found in the C-terminal half. A similar recognition pattern was observed in FMD-convalescent guine apigs, swine and cattle. Anti-chaperonin 10 sera showed antiviral activity against FMDV-infected BHK-21 cells. There was strong evidence that early af ter infection these cells actively secrete their histones and that antisera to the chaperonin recognize them. The same antisera reacted with purified histones in immunoblotting. Most important, exogenously added histones abro gated the anti-viral activity of the antiserum and an anti-histone monoclon al antibody had strong antiviral activity against FMDV-infected BHK-21 cell s. These results are consistent with previous reports on displacement of hi stones from the nuclear compartment and immune recognition of self-histones after viral infections. On the whole, they indicate that M. tuberculosis c haperonin 10 enables the immune system to react against early abnormalities of virus-infected cells; this is accomplished by antibody cross-reacting w ith histones released during virus infection.