RNA Extraction by Tissue
Each tissue offers a different window into the llama's immune repertoire. We match the sampling source to your project.
From immune cell to RNA encoding the VHH repertoire.
RNA encoding VHH domains is carried by the B lymphocytes and plasma cells of the immunized llama. These cells are distributed across several compartments — circulating blood, secondary lymphoid organs, bone marrow — whose accessibility and cell-subtype composition differ.
Tissue choice depends on the immunization stage, the repertoire diversity sought, and how invasive the sampling procedure can be. For the vast majority of projects, peripheral blood is sufficient; deeper lymphoid tissues are reserved for specific diversity or plasma-cell maturation needs.
Four immune compartments, four repertoire profiles.
Peripheral Blood
PBL / PBMC — standard routePeripheral blood lymphocytes (PBL) or peripheral blood mononuclear cells (PBMC) are isolated by density-gradient centrifugation after each blood draw. This is the least invasive source: it can be repeated at several points of the immunization schedule to track how the repertoire evolves through successive boosts, with no surgical procedure.
Lymph Nodes
High B-cell diversityLymph nodes are the site where activated B lymphocytes mature. After the final immunization boosts, they are particularly rich in plasma cells producing high-affinity antibodies, allowing libraries to be enriched with clones already matured through somatic hypermutation.
Spleen
Lymphoid reservoirA major secondary lymphoid organ, the spleen is used when a deeper tissue access is required to maximize representation of the immune repertoire, complementing or replacing peripheral blood.
Bone Marrow
Mature plasma cellsBone marrow hosts long-lived plasma cells. It is a complementary source for projects requiring a repertoire of mature, time-stable antibodies representative of an established immune memory.
Which tissue for which goal?
| Tissue | Invasiveness | Diversity / profile | Use case |
|---|---|---|---|
| Peripheral blood (PBL/PBMC) | Minimal — blood draw | Standard, repeatable over time | Routine immune library construction |
| Lymph nodes | Moderate | High in mature plasma cells | Enrichment in high-affinity clones |
| Spleen | Invasive | Very high, broad representation | Projects requiring maximal diversity |
| Bone marrow | Moderate to invasive | Long-lived plasma cells | Mature, time-stable antibody repertoire |
Extraction performed immediately after sampling.
Cell isolation
PBL/PBMC are isolated by density-gradient centrifugation (e.g. Ficoll) directly after the blood draw.
Total RNA extraction
Total RNA is extracted using a reference guanidinium thiocyanate–phenol–chloroform method, performed without delay to limit degradation.
Reverse transcription
Messenger RNA is converted to cDNA via oligo(dT) priming, the starting point for subsequent amplification of the VHH repertoire.
Quality control
Each extract is quantified and its integrity assessed before validation — see our dedicated quality control page.