In creating a recombinant subunit vaccine, a gene for an antigen is inserted into a plasmid. Which most accurately and completely describes what happens next?
The plasmid digests the antigen, completely destroying it.
The plasmid will produce large quantities of the antigen.
The plasmid is placed into a host cell, and produces antibodies.
The plasmid is placed into a host cell which then produces large quantities of antibody.
The plasmid is placed into a host cell which then produces large quantities of the antigen.
The correct answer and explanation is :
The correct answer is:
The plasmid is placed into a host cell which then produces large quantities of the antigen.
Explanation:
Plasmids are small, circular DNA molecules that are separate from the chromosomal DNA of a cell. They are commonly used in genetic engineering to introduce foreign genes into a host cell, allowing the cell to express those genes and produce the desired protein or antigen. Here’s how it works in detail:
- Plasmid Design: A plasmid can be engineered to carry a specific gene of interest. In this case, the gene encodes an antigen. An antigen is typically a foreign substance, like a part of a pathogen (virus, bacteria, etc.), that stimulates the immune system to produce antibodies.
- Transformation of Host Cells: The plasmid carrying the gene for the antigen is introduced into a host cell through a process called transformation. This can be done through various methods such as chemical transformation, electroporation, or viral delivery. The host cell is typically a bacterium (such as E. coli) or a eukaryotic cell line, depending on the application.
- Gene Expression: Once the plasmid is inside the host cell, the cell’s machinery reads the foreign gene and begins to produce the corresponding protein — in this case, the antigen. This is because the plasmid contains sequences that allow the host cell to transcribe and translate the gene into a protein.
- Large-Scale Production: The host cell replicates, and as it divides, it continues to produce the antigen in large quantities. This can be scaled up by growing large cultures of the host cells, thereby producing substantial amounts of the antigen.
- Antigen Use: The produced antigen can be harvested from the host cells for various applications. For instance, it can be used in vaccines to trigger an immune response, or it can be used in laboratory research.
In summary, the process of inserting a plasmid with an antigen gene into a host cell results in the production of large quantities of the antigen, which is a crucial step in biotechnology and pharmaceutical applications, such as vaccine development.