Individual B cells transcribe multiple rearranged immunoglobulin light chains in teleost fish

Pedro Perdiguero; Esther Morel; Patricia Díaz-Rosales; Carolina Tafalla

doi:10.1016/j.isci.2021.102615

Individual B cells transcribe multiple rearranged immunoglobulin light chains in teleost fish

iScience. 2021 May 24;24(6):102615. doi: 10.1016/j.isci.2021.102615. eCollection 2021 Jun 25.

Authors

Pedro Perdiguero¹, Esther Morel¹, Patricia Díaz-Rosales¹, Carolina Tafalla¹

Affiliation

¹ Animal Health Research Center (CISA-INIA), Valdeolmos, Madrid 28130, Spain.

Abstract

B cells express a unique antibody protein which comprises two pairs of immunoglobulin (Ig) heavy (H) and light (L) chains. In addition to an invariable constant (C) region, IgH and IgL chains encompass a variable (V) region mediating antigen binding. This unique region stems from Ig V(D)J gene recombination, which generates diversity by assembling these gene segments into V_HDJ_H and V_LJ_L genes. To ensure that one B cell only expresses one antibody, V_HDJ_H rearrangement occurs only in one IgH locus (allelic exclusion), whereas V_LJ_L rearrangement only in either the κ or λ locus (isotype exclusion). However, teleosts express multiple IgLs encoded by distinct C_L genes. Using single-cell transcriptomics, we have demonstrated the transcription of distinct rearranged V_LJ_LC_L genes in single rainbow trout B cells. Our results highlight the laxity of isotype exclusion in teleosts and strongly suggest that fish B cells can produce antibodies of different specificities.

Keywords: Cell biology; Immunology; Transcriptomics.