Molecular characterization of virus-induced autoantibody responses

Abstract

Here we present a comprehensive molecular mapping of virus-induced autoimmune B cell responses obtained by serological identification of antigens by recombinant expression cloning analysis. Immunoscreening of cDNA expression libraries of various organs (lung, liver, and spleen) using sera from mice infected with cytopathic (vaccinia virus [VV]) or noncytopathic (lymphocytic choriomeningitis virus [LCMV]) viruses revealed a broad specificity of the elicited autoantibody response. Interestingly, the majority of the identified autoantigens have been previously described as autoantigens in humans. We found that induction of virus-induced autoantibodies of the immunoglobulin G class largely depends on the CD40-CD40L-mediated interaction between T and B cells. Furthermore, antibody titers against a number of autoantigens were comparable to the concomitantly induced antiviral antibody response. Comparison of serum reactivity against a selected panel of autoantigens after infection with VV, LCMV, or vesicular stomatitis virus showed that the different virus infections triggered distinct autoantibody responses, suggesting that virus infections may leave specific "autoantibody fingerprints" in the infected host.

Figure 1.

Alignment of selected cDNA clones encoding different regions in ROCK1 and ROCK2. Nucleotide position of the respective clone is indicated in parenthesis.

Figure 2.

Rapid determination of seroreactivity pattern after viral infection. Phages from clones encoding for VV 39-kD immunodominant antigen, MYH6, GOLGB1, and ROCK2 were mixed with wild-type phage clones as negative control and used to transfect E. coli. After transfer onto nitrocellulose membranes, replica-plated phages were incubated with serial twofold dilutions of pooled serum from (A) mice infected with 2 × 10⁶ PFU VV (day 14 after infection) or (B) mice infected with 2 × 10⁵ PFU LCMV.

Figure 3.

Antibody responses directed against a selected panel of autoantigens (ROCK1 and ROCK 2), hsj2 (DNAJA1), MYH6, COL13A1 and GOLGB1, and VV antigens (VV39kD, immunodominant antigen; VV ATI, A-type inclusion protein) as determined on day 21 after infection by quantitative phage assay. (A) Antibody titers in pooled sera from five C57BL/6 mice infected with 2 × 10⁶ PFU VV, 200 PFU LCMV, and 2 × 10⁶ PFU VSV. (B) The role of T helper cells in the induction of autoantibodies was determined by infection with 2 × 10⁶ PFU VV of C57BL/6 mice, CD4-depleted mice, or CD40L-deficient mice.

Figure 4.

Time course of antibody responses against (A) VV proteins A-type inclusion protein and 39-kD immunodominant antigen, and (B) anti–self-antigens GOLGB1 and ROCK2 after infection of C57BL/6 mice with 2 × 10⁶ PFU VV or 200 PFU LCMV. Pooled sera from five mice were assayed by quantitative phage assay at the indicated time points after infection.