Virion glycosylation governs integrity and infectivity of infectious pancreatic necrosis virus

Fridholm, H; Everitt, E

The possible importance of the O‐linked glycosylation in virion stability and infectivity of infectious pancreatic necrosis virus (IPNV) was analysed. Enzymatic treatment with O‐glycosidase of radiolabelled virions under different ionic conditions, to allow for possible alternative exposure of glycosidic enzyme cleavage sites, did not alter the specific infectivity of virions re‐isolated after rate‐zonal centrifugation in glycerol gradients. As an alternative method to assess the significance of carbohydrates in IPNV integrity, periodate oxidation in the presence of an aldehyde quencher was chosen. Following re‐isolation of viruses, a 3–5 (10)log‐unit reduction in specific infectivity was revealed and, at higher concentrations, a total disruption or virion aggregation was observed. The loss of infectivity of intact virions was not because of a lack of attachment to cells. Additionally, re‐evaluation of reading values from UV‐spectra of purified IPNV yielded a specific infectivity of 3 × 10(11) TCID(50)‐units mg(−1) of protein and a ratio of 40 virions per TCID(50)‐unit in the CHSE‐214 cell system.