Establishment of detection antibodies BRRs batch 5 for in vitro potency assay of hepatitis A vaccines by ELISA.

The European Pharmacopoeia (Ph. Eur.) standard ELISA method for determination of antigen content of hepatitis A vaccines (HAV) requires specific coating and detection Biological Reference Reagents (BRRs). The 4th batch of detection antibodies BRRs was established in 2017 for use in conjunction with the Ph. Eur. General Chapter 2.7.14 Assay of hepatitis A vaccine. Stocks of these BRRs were running low and therefore the European Directorate for the Quality of Medicines and HealthCare (EDQM) organised a collaborative study to qualify replacement batches. The candidate BRR antibodies batch 5 were prepared under appropriate conditions from starting materials similar to previous batches to ensure continuity. Prior to the study, a low level of detection was obtained with new batches of the HRPO-GAM provided by the established supplier, supposedly due to a manufacturing issue in the conjugation step. Several other batches procured from the same supplier were tested without any success. Consequently HRPO-GAM batches from 3 other suppliers were tested and one batch was chosen to be included as a BRR based on its suitable characteristics. During the collaborative study, the new batches of antibodies were compared to previous batches of BRRs. Results confirmed that they were suitable to be used for the intended purpose, and could be used at the same final concentrations as the previous batch, i.e. 1:500 for the primary antibody and 1:400 for the conjugated secondary antibody. A higher background OD than in previous batches was observed, so it is recommended to subtract the background from the OD values obtained in the test in order to plot the sigmoid curve and calculate the titre of test samples. Moreover it is recommended that the first dilutions used for the IS and BRP2 should be 1:2 and 1:20, respectively, in order to achieve the same ODmax as for the previous BRRs batches. The BRRs were adopted by correspondence in October 2018 by the Ph. Eur. Commission and are presented as a set containing Hepatitis A virus primary detection antibody BRR batch 5 and Conjugated secondary detection antibody BRR batch 5. They are available from the EDQM as Hepatitis A vaccine ELISA detection antibodies set BRR batch 5.

Establishment of detection antibodies BRRs batch 4 for in vitro potency assay of hepatitis A vaccines by ELISA.

The European Pharmacopoeia (Ph. Eur.) standard ELISA method for determination of antigen content of hepatitis A vaccines (HAV) requires specific coating and detection Biological Reference Reagents (BRRs). The 3rd batch of detection antibodies BRRs was established in 2015 for use in conjunction with the Ph. Eur. general chapter 2.7.14 'Assay of hepatitis A vaccine'. Stocks of these BRRs were running low and therefore the European Directorate for the Quality of Medicines & HealthCare (EDQM) organised a collaborative study to qualify replacement batches. The candidate BRR antibodies batch 4 were prepared under appropriate conditions from starting materials similar to previous batches to ensure continuity. During the collaborative study, the new batches of antibodies were compared to previous batches of BRRs. Results confirmed that they were suitable to be used for the intended purpose, and could be used at the same final concentrations as the previous batch, i.e. 1:500 for the primary antibody and 1:400 for the conjugated secondary antibody. They were adopted in June 2017 by the Ph. Eur. Commission as Hepatitis A virus primary detection antibody BRR batch 4 and Conjugated secondary detection antibody BRR batch 4, respectively. They are available from the EDQM as Hepatitis A vaccine ELISA detection antibodies set BRR batch 4.

Establishment of hepatitis A vaccine (inactivated, non-adsorbed) BRP batches 2 and 3.

The current hepatitis A vaccine (HAV), inactivated, non-adsorbed, European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) is used for the in vitro potency assay of HAV as prescribed by the Ph. Eur. general chapter 2.7.14 Assay of hepatitis A vaccine. This reference preparation was calibrated in 2008 through an international collaborative study and was assigned a potency of 12 IU/mL. During use of this BRP it appeared to be inapplicable in certain cases due to a low nominal antigen content. Consequently, the European Directorate for the Quality of Medicines and HealthCare (EDQM) established replacement batches for this BRP, calibrated against the 1(st) WHO International Standard (IS) for HAV (inactivated), using the standard in vitro ELISA (enzyme-linked immunosorbent assay) method validated previously. The results of the study showed that the candidate BRPs were suitable for the intended purpose, and following completion of the study, they were adopted in November 2014 by the Ph. Eur. Commission as HAV (inactivated, non-adsorbed) BRP batches 2 and 3, with an assigned potency of 1350 IU/mL, for in vitro antigen content determination by ELISA. As the amount of material in each vial largely exceeds the amount required for the performance of a single assay, the BRPs are to be aliquoted by users as single-use aliquots and refrozen below -50 °C prior to their use as reference preparations.

Establishment of hepatitis A detection antibodies set BRR batch 3 for antigen content determination by ELISA.

The current batch of the European Pharmacopoeia (Ph. Eur.) Biological Reference Reagents (BRRs) used for the in vitro potency assay of hepatitis A vaccines (HAV) by ELISA (enzymelinked immunosorbent assay) was established in 2012 for use in conjunction with Ph. Eur. general chapter 2.7.14 Assay of hepatitis A vaccine. It is composed of a coating reagent and a set of detection antibodies. As stocks of the latter are running low, the European Directorate for the Quality of Medicines & HealthCare (EDQM) organised a collaborative study to qualify replacement batches. The candidate BRR antibodies (primary monoclonal antibody and labelled secondary antibody) were prepared under appropriate conditions from starting materials similar to those used for the current batches. The new batches of antibodies were tested alongside previous batches of BRRs to ensure continuity, and the results confirmed that they were suitable for use in the potency assay of hepatitis A vaccines by ELISA using the standard method referenced in Ph. Eur. general chapter 2.7.14 at the same final concentrations as the previous batches, i.e. 1:500 for the primary monoclonal antibody and 1:400 for the secondary conjugated antibody. The outcome of the study allowed their establishment by the Ph. Eur. Commission in March 2015 as anti-hepatitis A virus primary detection antibody BRR batch 3 and conjugated secondary detection antibody BRR batch 3 respectively. They are available from the EDQM as hepatitis A vaccine ELISA detection antibodies set BRR batch 3.