Biotechnology Terms Starting With C
Biotechnology Glossary: C
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Cell Culture
/ sel KUL-cher / · Latin cellula, small room; cultura, cultivation
Cell culture is the laboratory technique of growing cells outside a living organism under controlled conditions, providing experimental access to living biological material.
Cells are maintained in sterile vessels containing nutrient-rich growth media supplemented with serum, growth factors, and hormones at 37 degrees C in humidified CO2 incubators. Adherent cells grow attached to surfaces, while suspension cells grow freely in liquid medium, and the choice influences experimental technique and scale-up strategy. HeLa cells, derived from a cervical cancer patient in 1951, became one of the first human cell lines cultured continuously and remain in use today.
Cell culture underpins vaccine production, drug testing, tissue engineering, and cancer research.
The first polio vaccine, developed by Jonas Salk in 1955, depended on virus grown in monkey kidney cells maintained in culture, demonstrating that large-scale cell culture could produce enough biological material to protect millions of people within a single year.
How To Become An Oncologist? →Cultured cells behave exactly like cells inside an organism. Cells can change gene expression patterns, lose tissue-specific functions, and accumulate mutations when removed from their natural tissue environment.
HeLa cells (Henrietta Lacks) are among the most widely distributed human cell lines in research history, present in laboratories across more than 100 countries. Researchers have used them to study viral replication, radiation effects, and cancer biology, and the genome of the HeLa cell line was sequenced and published in 2013.
Chimeric Antigen Receptor
/ ky-MEER-ik AN-tih-jen reh-SEP-ter / · Greek chimaira, fire-breathing monster; Latin antigenum
Chimeric Antigen Receptor is an engineered protein that combines an antibody-derived antigen-binding domain with T cell signaling domains, directing T cells to recognize and kill tumor cells that display a specific surface antigen.
CAR-T cell therapy involves isolating a patient’s T cells, transducing them with a gene encoding the CAR, expanding them in culture, and reinfusing them to target cancer cells bearing the cognate antigen. Approved CAR-T therapies targeting CD19 have achieved complete remission in over 80% of patients with certain relapsed or refractory B cell leukemias. Current challenges include cytokine release syndrome, neurotoxicity, antigen escape, and high manufacturing costs that limit accessibility.
The first CAR-T therapy approved by the FDA in 2017, tisagenlecleucel, costs approximately $475,000 per patient for a single treatment. Despite this cost, over 90% of children with relapsed B-cell acute lymphoblastic leukemia achieved complete remission within three months of receiving this therapy.
Immune System Fun Facts →CAR-T cells are ordinary donated immune cells. Each CAR-T product is manufactured from a specific patient's or matched donor's T cells, which are then genetically engineered to carry a new receptor before being returned to that patient.
CAR-T cells targeting CD19 have produced durable remissions in patients with diffuse large B cell lymphoma, a cancer that had relapsed after two or more prior lines of chemotherapy. In the JULIET clinical trial, 40% of patients who received tisagenlecleucel maintained a complete response at 12 months.
Chromosome Walking
/ KROH-moh-sohm WAW-king / · Greek chroma, color; soma, body
Chromosome walking is a technique for mapping and cloning a region of interest in a genome by using overlapping clones to progressively extend coverage away from a known sequence landmark.
Starting from a known sequence, a DNA probe screens a genomic library for overlapping clones, and the end of each clone then provides the probe for the next round of screening. By iterating this process, researchers can travel along the chromosome, cloning large genomic regions without knowing the sequence in advance. Before whole-genome sequencing became routine, chromosome walking was a primary strategy in positional cloning, most notably contributing to the identification of the cystic fibrosis gene CFTR in 1989.
Each successive step typically covers 30 to 150 kilobases of genomic DNA, depending on clone insert size.
Chromosome walking contributed to identifying the Huntington's disease gene in 1993, a search that took a decade of collaborative work across multiple research groups and spanned a 4-megabase region of chromosome 4 before the causative trinucleotide repeat expansion was pinpointed.
Chromosome walking means watching chromosomes move under a microscope. It is a DNA mapping and cloning strategy that works entirely at the molecular level, using overlapping DNA fragments to traverse a genomic region.
Pros and Cons of Cloning →Researchers used chromosome walking to close in on the CFTR gene responsible for cystic fibrosis, beginning from a linked genetic marker on chromosome 7. Each overlapping clone extended coverage by tens of kilobases until the gene region was isolated and sequenced in 1989.
Combinatorial Library
/ kom-by-nah-TOR-ee-ul LY-brer-ee / · Latin combinare, to combine; libraria
Combinatorial library is a large collection of systematically varied chemical compounds or biomolecules generated simultaneously to enable high-throughput screening for biological activity.
Chemical combinatorial libraries use split-and-pool synthesis or parallel synthesis to create thousands to millions of drug-like molecules differing in defined structural positions. Biological combinatorial libraries include phage display libraries, where random peptide or antibody sequences are displayed on bacteriophage surfaces and screened for binding to a target protein. A single phage display library can contain more than 10 billion unique peptide sequences, giving researchers access to enormous molecular diversity in a single screening campaign.
Combinatorial approaches have dramatically accelerated early-stage drug discovery by compressing into weeks a search that would otherwise take years of individual synthesis.
George Smith developed phage display in 1985, and the technology was later refined by Gregory Winter to generate fully human antibody libraries. This work contributed to the development of adalimumab (Humira), the best-selling drug of the early 21st century, which was identified by screening a combinatorial antibody library rather than by immunizing animals.
Scientists design every candidate molecule one at a time before testing it. A combinatorial library generates thousands or millions of structural variants simultaneously, so screening and synthesis happen in parallel rather than sequentially.
Phage display libraries have been used to identify peptides that bind the spike protein of SARS-CoV-2. Researchers screened libraries of more than one billion phage-displayed peptide sequences to find candidates with nanomolar binding affinity for use as diagnostic or therapeutic leads.