Recombinant IgA production: single step affinity purification using camelid ligands and product characterization

Area of Science:

• Biotechnology
• Immunology
• Biochemistry

Background:

• Immunoglobulin A (IgA) is crucial for mucosal immunity.
• Challenges exist in producing sufficient IgA for therapeutic and research applications.
• Recombinant antibody production offers a potential solution but faces expression and purification hurdles.

Purpose of the Study:

• To establish stable recombinant Chinese hamster ovary (CHO) cell lines for IgA1 antibody production.
• To develop an efficient and generic purification strategy for recombinant IgA.
• To compare the novel purification method with traditional multi-step chromatography.

Main Methods:

• Stable expression of two IgA1 antibodies in serum-free recombinant CHO cells.
• Characterization of specific productivities and J chain assembly of polymeric IgA.
• Development of a single-step purification using an immobilized camelid anti-human alpha-chain VHH ligand.
• Comparison with a multi-step purification process involving jacalin affinity, anion exchange, and hydrophobic interaction chromatography.

Main Results:

• Successfully established recombinant CHO cell lines expressing IgA1 with varying productivities.
• Demonstrated J chain assembly and expected specificity of polymeric IgA in crude supernatants.
• Achieved high purity and yield of both recombinant IgAs in a single VHH ligand chromatography step.
• The VHH ligand method proved superior to the multi-step purification process.

Conclusions:

• The developed VHH ligand capture step is a robust and generic method for isolating recombinant IgA, regardless of light chain or specificity.
• This method significantly simplifies IgA purification, facilitating further in vivo exploration and therapeutic development.
• The findings address key challenges in recombinant IgA production and purification, paving the way for advanced immunotherapies.