The variable regions of the alpha and beta chains each have three hypervariable or complementarity-determining regions (CDRs). The CDR3 is the central region to recognize processed antigens. To identify as many antigens as possible, the TCR repertoire is highly diverse. Its diversity originates from recombination, more precisely, the V(D)J recombination, where variable (V), joining (J), and diversity (D) gene segments are randomly rearranged. This V(D)J recombination allows the recognition of almost all pathogens.
However, V(D)J recombination is not only a pivotal part of the development of the TCR repertoire; it is also responsible for the highly diverse repertoire of antibodies. The antibody molecules, including the B-cell receptors, comprise a heavy and light chain. As for the TCRs, the subunits consist of variable (V) and constant (C) regions. Additionally, they contain joining (J) gene segments. The heavy chains also include diversity (D) gene segments. By this recombination, at least 1011 different antibody molecules are formed.
With single-cell immune profiling, the B-cell receptor and T-cell receptor sequences can be sequenced and analyzed at a single-cell resolution. Hundreds to tens of thousands of cells can be analyzed in a single run. In addition to the analysis of the complete immune repertoire, the gene expression of the T and B cells can be investigated, giving insights into the adaptive immune system at single cell level. Single-cell immune profiling helps you explore your samples’ immune cell diversity and increase the understanding of the adaptive immune system.