Phenotypic analysis of peripheral leukocytes in piglets infected with classical swine fever virus

The phenotypic changes in circulating leukocytes in swine fever influenced by classical swine fever virus (CSFV) infection with different strain virul ence was studied in piglets. The phenotypic differences were measured by mo noclonal antibodies specific for porcine differentiation antigens. The patt ern of phenotypic change varied with the virulence of CSFV. Infection with virulent, but not the attenuated strain of CSFV resulted in the dramatic ea rly loss of CD8-bearing T lymphocytes from the circulation A similar trend was also seen in the gamma delta T-cell compartment following infection wit h the highly virulent strain, Washington. The loss of circulating B-lymphoc ytes was consistent with the failure to generate neutralising antibody. The se observations contrasted the finding that the number of leukocytes expres sing the CD4 surface antigen increased in piglets infected with CSFV. These data provide preliminary information on the potential range of leukocyte c hanges produced in piglets following infection with CSFV.