Antibody response to IR6, a conserved immunodominant region of the VlsE lipoprotein, wanes rapidly after antibiotic treatment of Borrelia burgdorferiinfection in experimental animals and in humans

Invariable region (IR)(6), an immunodominant conserved region of VISE, the antigenic variation protein of Borrelia burgdorferi, is currently used for the serologic diagnosis of Lyme disease in humans and canines. A longitudin al assessment of anti-IR, antibody levels in B. burgdorferi-infected rhesus monkeys revealed that this level diminished sharply after antibiotic treat ment (within 25 weeks). In contrast, antibody levels to P39 and to whole-ce ll antigen extracts of B. burgdorferi either remained unchanged or diminish ed less. A longitudinal analysis in dogs yielded similar results. In humans , the anti-IR6 antibody titer diminished by a factor of greater than or equ al to4 in successfully treated patients and by a factor of <4 in treatment- resistant patients. This result suggests that the quantification of anti-IR 6 antibody titer as a function of time should be investigated further as a test to assess response to Lyme disease therapy or to determine whether a B . burgdorferi infection has been eliminated.