Aims: To characterize the specificity and effect of pH and ionic strength on the kinetics of virus binding to histo‐blood group antigens (HBGA)‐conjugated magnetic beads.
Methods and Results: HBGAs from porcine gastric mucin (PGM) have been conjugated to magnetic beads (PGM‐MB) for concentration of NoV. A GII.4 virus was used for the detailed binding kinetics study and a panel of genogroup I (GI) NoVs, genogroup II (GII) NoVs and recombinant NoVs (rNoVs) were used for specificity and binding efficiency assays. We determined that NoV can be captured after 15 min of incubation with PGM‐MB, and virus recovery efficiency is decreased after extended incubation times. rNoV binding as measured by ELISA and NoV recovery as measured by quantitative reverse transcriptase‐polymerase chain reaction (RT‐PCR), were both enhanced significantly at acidic pH conditions. rNoV binding to PGM as measured by ELISA was increased up to 66%. While real‐time RT‐PCR analyses suggest that NoV could be concentrated as much as 1000‐fold at neutral pH, up to 3·4‐fold further increase of NoV recovery was achieved by adjusting the pH of the sample to 3·0–4·2. Variation between GI and GII viral binding to the PGM‐MB at basic pH was observed. All five GI rNoVs tested and 6 of 9 GII rNoVs were captured by PGM. All eight GI strains tested were concentrated by PGM‐MB, ranging from 28‐fold (GI.4) to 1502‐fold (GI.1). Eleven of 13 GII strains were concentrated from 30‐fold (GII.5) to 1014‐fold (GII.4, lab strain) by PGM‐MB. GI and GII rNoVs viral capsid proteins were recovered with high salt conditions, but results were inconsistent for whole virus recovery.
Conclusions: All GI and 85% of GII NoVs tested could be captured and concentrated by PGM‐MB method. The binding occurred rapidly and was enhanced at low pH.
Significance and Impact of the Study: These results facilitated development of a prototype method for sensitive detection of NoV in samples requiring larger volumes.