Enhancement of antibody activity to bovine leukemia virus by complement

Abstract

Cocultivation of fetal lamb kidney cells infected with bovine leukemia virus (BLV) and the cat cells containing murine sarcoma virus genome resulted in the rapid production of syncytia. This syncytia formation was inhibited by serum containing antibodies to glycoprotein antigen of BLV. When rabbit complement was added to the antiserum for early syncytia inhibition (ESI) test, a significant enhancement of ESI activity of the antiserum was observed. This enhancement was associated with IgG fraction but not with IgM fraction of the antiserum. The results of the comparative serological tests showed that the ESI test with complement was much more sensitive than either immunodiffusion or complement fixation tests in the detection of BLV antibodies.

Neutralizing antibody response of rabbits and goats to caprine arthritis-encephalitis virus

“…This has been noted in other virus systems, and it has been suggested that this fraction represents (i) reversible complexes, (ii) viral aggregates which cannot be completely neutralized, (iii) complexing with blocking, nonneutralizing antibody, or (iv) a genetically resistant subpopulation (9,18). Complement-dependent neutralization has been demonstrated for a number of viruses, especially enveloped viruses (27,28). Whether neutralization of sensitized CAEV after the addition of complement involved "virolysis" (22) or other mechanisms, including aggregation or steric hindrance of virus adsorption caused by the binding of complement components, was not determined.…”

Production of Monoclonal Antibodies Specific for Ganglioside GD31

“…Monoclonal antibodies from culture fluid were purified by precipitation with 50% ammonium sulfate, followed by Sephadex G-200 (Pharmacia Fine Chemicals, Uppsala, Sweden) gel filtration (53). The amount of protein was estimated by using Bio-Rad protein assay kit (Bio-Rad Laboratories, Richmond, Calif.).…”