GMP Compliance for Production of CB.Hep-1 Monoclonal Antibody as a Biological Reagent




The mouse monoclonal antibody (MAb) known as CB.Hep-1 is secreted by the hybridoma 48/1/5/4, specific for the "a" determinant of the Hepatitis B surface antigen (HBsAg). This MAb is routinely used for the immunopurification of recombinant Hepatitis B surface Antigen (rHBsAg) for vaccine purposes. Considering the application of this MAb and issues raised by regulatory agencies for the manufacture of biological products, a documentation system and methods to control the MAb production process were established.

Starting in 1991, the department responsible for immunosorbents CB.Hep-1 production has followed Good Manufacturing Practices (GMPs) regulations by establishing a complete documentation system, in which the main objective has been to guarantee stable and solid production processes for the preparation of biopharmaceutical products.

The principal recommendation in this paper is the application of the MAb as a biological reagent in the drug substance manufacturing process where the MAb is used to purify the drug substance.

Several issues that may be useful in developing a regulatory strategy for monoclonal antibodies used as reagents are discussed.

A Good Manufacturing Practice (GMP) system constitutes an associated group of norms and activities destined to guarantee that every product meets and retains the characteristics of design required for its use. The GMPs also minimize unforeseen risks that may occur during the screening of the final product.1 These norms establish requirements for the production of drugs for human use on both medium and large-scale manufacture. Confor-mance to GMPs is basic for state-of-the-art quality systems.

The documentation system is the essential part of any quality system; therefore, it should be based on the GMPs and must comply with all relevant aspects for the production and commercialization of the products. During the production, control, and administration of any pharmaceutical product, special care must be taken because of the many chemical biological substances, live organisms (cells), and various production processes that could be involved. These variables demand that any documentation system provide all possible information about the history of the product from the very beginning of the production process and must fulfill all regulatory requirements for these kinds of products.2

The technique of Köhler and Milstein involves immortalizing antibody-producing plasma cells from an immunized mouse by fusion with myeloma cells (a plasma cell tumor line).3 The resulting hybrid cells or hybridomas can be maintained in vitro or in vivo to continuously secrete large quantities of MAb with a defined specificity and can be purified and used in a variety of applications.4, 5

The main characteristic of these products is that they are produced by mammalian cells in culture or are taken directly from an animal. In both cases, the starting material is capable of harboring adventitious agents — generally viruses that can result in significant harm to humans.6 Process validation is an important tool for the evaluation of biotherapeutic products, such as MAbs obtained from mice.

In this paper we introduce and apply applicable GMP elements and a documentation system that supports process consistency in the production of immunosorbent CB.Hep-1.

CB.HEP-1 MONOCLONAL ANTIBODY (ANTI-HBSAG) IMMUNOAFFINITY MATRIX

The production process of MAb CB.Hep-1 includes four main steps:
1. Conformation of the cell banks and inoculum
2. Ascites production
3. Immunoglobulin G (IgG) purification
4. Immobilization on Sepharose CL 4B7


Figure 1. Flowchart of the Immunosorbent CB.Hep-1 Production and Controls
In every step, several unitary operations, processes, and quality controls are carried out. All data generated during this process has been analyzed using the Microsoft Excel software version 7.0. (See Figure 1)