Synthetic peptide-derived antibody-based immunohistochemistry for the detection of porcine circovirus 2 in pigs with postweaning multisystemic wasting syndrome.

Porcine circovirus 2 (PCV2) was detected consistently in formalin-fixed paraffin wax-embedded lymph node and spleen from experimentally and naturally infected pigs by synthetic peptide-derived polyclonal antibody-based immunohistochemistry. Synthetic peptides were generated from open reading frame 2 of PCV2 by solid-phase peptide synthesis, purified by high performance liquid chromatography, and injected into rabbits to produce polyclonal antibody. Positive cells had large nuclei with abundant cytoplasm, and resembled macrophages. In serial sections, a similar distribution of PCV2 antigen and DNA was confirmed in virus-infected cells by immunohistochemistry and in-situ hybridization, respectively. The immunohistochemical method described was successfully applied to formalin-fixed, paraffin wax-embedded tissues and should prove helpful in diagnosing postweaning multisystemic wasting syndrome.