PROMINENT T-LYMPHOCYTE RESPONSE TO BORRELIA-BURGDORFERI FROM PERIPHERAL-BLOOD OF UNEXPOSED DONORS

The proliferative response of peripheral blood T cells to the spiroche te, Borrelia burgdorferi, can be as pronounced in unexposed normal ind ividuals as it is in Lyme disease patients. This finding was observed using three geographically distinct isolates of B. burgdorferi. The re sponse is not due to a lipopolysaccharide effect of the spirochete, is sensitive to Proteinase K, and requires antigen processing. It does n ot result from cross-reactivity of memory T cells that may be reactive to another antigen; the proliferative response to B. burgdorferi is e qually distributed between naive (CD29(-), CD45RO(-)) and memory (CD29 (+), CD45RO(+))T cells, whereas the tetanus response is confined to th e memory subset. In support of this notion, cord blood specimens that contain almost entirely naive T cells, respond as vigorously to B. bur gdorferi as T cells from normal adult peripheral blood. A large panel of CD4(+) T cell clones has been derived that are specific for B. burg dorferi. The majority of these clones are reactive to B. burgdorferi i n the presence only of autologous HLA-DR molecules. Collectively, thes e data suggest that the T cell response from normal individuals is mor e likely due to multiple antigenic epitopes within Borrelial proteins than a superantigen response.