Dynamics of cell-associated viremia and antibody response during the early phase of lentivirus infection in sheep
Juste, R.A.; Kwang, J.; de la Concha-Bermejillo, A.
American Journal of Veterinary Research 59(5): 563-568
1998
ISSN/ISBN: 0002-9645 PMID: 9582957 Document Number: 497475
Of 18 newborn lambs, 12 were inoculated intratracheally with ovine lentivirus (OvLV) within 24 h after birth and 6 were inoculated with uninfected cell culture supernatant. Degree of cell-associated viraemia was measured every other week for 16 weeks using a limited dilution assay. Antibody responses to OvLV transmembrane (TM) and p25 proteins were determined weekly using a recombinant ELISA. Neutralizing antibody responses were measured before and 8 and 16 weeks after inoculation. Degree of cell-associated viraemia peaked between 2 and 6 weeks after inoculation and then decreased. For inoculated lambs, mean anti-p25 titre peaked 5 weeks after inoculation then slowly declined, whereas mean anti-TM and neutralizing antibody titres increased steadily. Over time, mean degree of cell-associated viraemia was negatively correlated with mean anti-TM titre. Maximum individual degree of cell-associated viraemia was positively correlated with maximum individual anti-TM titre. It is suggested that after experimental inoculation, OvLV replicates actively for several weeks and that an increase in anti-TM titre coincides with a decrease in degree of cell-associated viraemia. It is also suggested that although the role antibodies play in protecting against lentivirus infection remains uncertain, understanding the dynamics of the antibody response may have important implications for diagnosis of OvLV infection, and antibodies may prove to be valuable markers for prediction of infection and disease.