Lyme disease is caused by the spirochete Borrelia burgdorferi. Two ubiquitous lipids of Borrelia burgdorferi, BBGL1 and BBGL2, comprise 35% of the total lipid mass of the bacteria and are specifically synthesized by pathogenic Borrelia spp. It is known from previous studies that BBGL2 can bind to CD1d and activate CD1d restricted NKT cells. In this study, we carried out FACS-sorting with CD1b-BBGL2 tetramers, to obtain a T cell line from a Lyme disease patient that recognizes BBGL2 presented by CD1b. The T cell clone binds to CD1b-BBGL2 tetramers but not to mock loaded CD1b tetramers or CD1b loaded with the negative control lipid phosphatidylglycerol. Although there is specific recognition of the CD1b-BBGL2 complex using tetramers, the primary T cells produce comparable levels of IFN-γ in an ELISPOT assay when stimulated with CD1b-expressing antigen presenting cells in the presence or absence of BBGL2 lipid. The TCR sequence was determined by single cell sequence and by transduction of the TCR we demonstrated that BBGL2 specificity was mediated by the TCR. Whereas the primary T cells preferably bind to CD1b tetramers loaded with BBGL2, we think that the activation by antigen presenting cells without the addition of BBGL2 is caused by a combination of a low affinity interaction with endogenous lipid-loaded CD1b and a high expression level of CD1b on the antigen presenting cells. We call this phenomenon “antigen-modulated autoreactivity” against the CD1b molecule, where there is an increased reaction to an antigen over a baseline autoreactivity of the T cell towards CD1b. Currently, more Lyme disease patients are being screened for the presence and frequency of CD1b-BBGL2 specific T cells using CD1b tetramers.