Immunoblots of lysates of HeLa cells infected with different Vaccinia virus (VV) recombinants. Full length (lanes 1 and 2) and truncated (lanes 5–8) IncA bands are indicated with brackets. Control VV-infected cells are in lane 3 and uninfected cells are in lane 4. As previously reported [4,8], full length C. caviae IncA migrates as three isoforms when produced during chlamydial infection (lane 1) or when expressed via a VV vector (lane 2). Lane 8 shows that truncated wild type IncA (residues 1 to 153) encoded by VV also is represented as three similar isoforms. Mutation of serines or threonines in the truncated incA are represented in lanes 5 (S17A), lane 6 (S121A) and lane 7 (T145A). Molecular mass standards are indicated in kilodaltons. The arrow indicates a background VV band recognized by the anti-incA antisera in some samples.