Age-Dependency of Swine Antibody-Dependent Cellular Cytotoxicity Against Pseudorabies Virus-Infected Cells

105 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1987.Pseudorabies is an age-dependent infectious disease primarily of swine caused by pseudorabies virus (PRV), a member of the herpesvirus family. The reasons for age-dependency of PRV are not known, but in some herpesvirus infections resistance was associated with macrophage maturation. In pigs, immunity against PRV infections involves both cellular and humoral immune responses. Antibody-dependent cellular cytotoxicity (ADCC) which involves both cell functions and antibodies might prove to be important in protection against PRV. Therefore, the age differences and age development of ADCC in pigs were studied. In this study it was demonstrated that ADCC activity in young pigs peripheral blood leukocytes (PBLs) against PRV-infected PK-15 cells was lower than that of adults and matured with age reaching adult levels by about 3 months of age. Modification and variation of assay conditions did not eliminate differences in ADCC activity between young and adult pigs PBLs. The most potent ADCC effector cell in the PBLs was found to be the polymorphonuclear leukocyte (PMNLs). However, deficiency in ADCC activity in young pigs was not related to lack of effector cells, presence of suppressor cells or suppressor factors, but rather due to a deficiency in the ability of PMNLs to bind anti-PRV sensitized PRV-infected targets. Additionally, PBLs from adult pigs reduced virus yields in infected targets by virtue of their ADCC activity. Such reduction was absent with young pig PBLs that lacked ADCC activity. Infection of PBLs with PRV did not lead to virus replication except in the adherent cells which constitute 3 to 10% of the PBLs. However, this infection did not affect viability or ADCC activity in total PBLs. Infection of pulmonary lavage cells (PLCs) on the other hand supported virus replication and led to loss of viability and ADCC activity. Therefore, while lung defenses might be compromised by PRV infection, PBLs could function in limiting virus spread in the body by virtue of their ADCC activity.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD