Correct Answer: (A) Antibody expressed in transgenic plant

Plantibody refers to functional antibodies (immunoglobulins) produced by genetically engineering plants to express mammalian antibody genes, leveraging plant protein folding machinery for cost-effective bioproduction. This term specifically denotes the antibody protein itself, not the plant host.

Option Analysis

(A) Antibody expressed in transgenic plant: Correct. Plantibodies are recombinant antibodies assembled in plant cells (e.g., tobacco via Agrobacterium transformation), accumulating up to 1-5% of soluble leaf protein with antigen-binding activity equivalent to mammalian systems.

(B) Transgenic plant that expresses antibody: Incorrect. This describes the plant bioreactor (host), not the antibody product. The plantibody is the output protein, not the producing organism.

(C) Antibody against plant based antigen: Incorrect. Plantibodies target diverse antigens (viral, bacterial, tumor); specificity arises from engineered variable regions, not plant origin.

(D) Transgenic plant that expresses antigen: Incorrect. This produces plant-based vaccines/antigens, not antibodies. Plantibody technology synthesizes immunoglobulins, not their targets.

Plantibody is the antibody expressed in transgenic plant, revolutionizing biopharmaceutical production since 1989 when tobacco first assembled functional mouse IgG at 1.3% leaf protein.​

Plantibody Production Process

• Antibody heavy/light chain cDNAs cloned into plant expression vectors.

• Agrobacterium-mediated transformation of leaf explants.

• Sexual crossing assembles full IgG; leader sequences boost yields 10-fold.

• Extraction yields functional antibodies with native affinity.

Advantages Over Mammalian Systems

• No human pathogens; scalable via planting.

• 1-10 g antibody/kg fresh biomass vs. $1000s/g in CHO cells.

• Edible delivery (e.g., antibody bananas for oral therapy).​

Applications

• Plantibodies 6D4 catalyze viral glycoproteins; Guy’s 13 sequesters root pathogens.

• Clinical trials for HIV, West Nile antibodies in corn/soy.

• Pandemic response: COVID plantibodies produced in weeks.