Protective Resistance to Experimental Borrelia burgdorferi Infection of Mice by Adoptive Transfer of a CD4+ T Cell Clone

The anti-spirochete T cell immune response to immunization with Borrelia burgdorferi was investigated. The cellular immune response to vaccination of immunocompetent BALB/c mice was characterized initially in vitro by assay of the proliferative response of primary lymph node cells to B. burgdorferi sonicate. Subsequently, an anti-spirochete T cell line (RBN2.1) and clone (97.1) were derived from lymph node cells of BALB/c mice primed with B. burgdorferi antigen. Both the line and clone were CD4+ by flow cytometric analysis. Significantly, RBN2.1 and clone 97.1 were able to transfer resistance to infection to syngeneic naive recipients. Assay of antigen-specific interleukin-2, interleukin-4, tumor necrosis factor-α, and interferon-γ production demonstrated that clone 97.1 was of the Th2 subclass. When B. burgdorferi sonicate was fractionated on SDS--PAGE and then electroeluted, clone 97.1 was reactive exclusively to a spirochete protein of approximately 21 kDa. These data suggest that T-cell-mediated protective immunity to infection by B. burgdorferi can be elicited by active immunization.