ABSTRACT
An Indian isolate of infectious bursal disease virus, i.e. IBDV-P/AD/81, was analysed for immunogenic activity of its structural polypeptides. Virus was purified from infected bursal homogenate by sucrose density gradient centrifugation. It showed five different structural polypeptides of 75.8, 45, 40.7, 33.1 and 27 kDa molecular weights in sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Anti infectious bursal disease virus (IBDV) antibodies were tested using enzyme-linked immunosorbent assay (ELISA) and neutralization test (NT). Polypeptide 40.7 kDa (VP2) was known to have neutralizing epitopes. However, polyclonal anti VP2 failed to neutralize the virus. It was interpreted that VP2 had labile neutralizing epitopes which get altered confirmationally by SDS. Surprisingly, polyclonal anti 33.1 kDa (VP3) had mild neutralizing activity.
Subject(s)
Animals , Chickens , India , Infectious bursal disease virus/chemistry , Peptides/immunology , Viral Proteins/immunologyABSTRACT
Conditions influencing production kinetics of bovine interleukin 2 (IL-2), viz. cell concentration, mitogen and its concentration, length of incubation, nutrient medium and in vivo antigen-priming were investigated. Peripheral blood mononuclear cells (PBL) of outbred cattle of different age groups showed considerable variation in their ability to secrete IL-2 which possibly reflects their immune competence. Of the cultures initiated with PBL, 5 x 10(6) cells/ml cultured in serum free Iscove's medium and stimulated with 5 micrograms Con A/ml for 24 hr produced maximal amount of IL-2 activity. In vivo antigen-priming of bovine lymphocytes with the live attenuated rinderpest virus revealed that IL-2 production was not affected by rinderpest virus but the in vivo antigen-priming possibly resulted in concomitant production of suppressor factor(s) which suppressed the already produced IL-2. The implications of this factor(s) in relation to regulation of immune responses in the disease process are discussed.