Preferential utilization of conserved immunoglobulin heavy chain variable gene segments during human fetal life.

Abstract

The ability to respond to specific antigens develops in a programmed fashion. Although the antibody repertoire in adults is presumably generated by stochastic combinatorial joining of rearranged heavy variable, diversity, andjoining (VH-DH-JH) and light (VL-JL) chains, experimental evidence in the mouse has shown nonrandom utilization of variable gene segments during ontogeny and in response to specific antigens. In this study, we have performed sequence analysis of 104-day human fetal liver-derived, randomly isolated constant region C, transcripts and demonstrate a consistent preference during fetal life for a small subset of three highly conserved VH3 family gene segments. In addition, the data show that this preferential gene segment utilization extends to the DHQ52 and the JH3 and JH4 loci. Sequence analysis of two "sterile" DH-JH transcripts suggests that transcriptional activation of the JH-proximal DHQ52 element may precede initiation of DH-JH rearrangement and influence fetal Do utilization. Sequence comparisons reveal striking nucleotide polymorphism in allelic gene segments which is poorly reflected in the peptide sequence, implying considerable evolutionary selection pressure. Although vertebrate species utilize a variety of strategies to generate their antibody repertoire, preferential utilization of VH3 elements is consistently found during early development. These data support the hypothesis that VH3 gene segments play an essential role in the development of the immune response.Immunoglobulins are generated by combinatorial joining of rearranged gene segments of the heavy chain variable, diversity, and joining regions (VH, DH, and JH) and light chain regions (VL and JL) (1). Starting with less than 1000 of these germ-line elements, more than 109 different antigen binding sites can be generated even in the absence of eitherjunctional diversity or somatic mutation. In mice, only a small fraction of this potential repertoire seems to be expressed as functional antibody (2). Utilization of this repertoire appears to be developmentally regulated in a strain-specific fashion (3-5) with subsequent modification by environmental stimuli (7).The human neonate is relatively immunodeficient at birth (8). Controlled mobilization of germ-line variable gene segments has been postulated to underlie, in part, the maturation of humoral immunity (5, 9). With these observations in mind, we have concentrated on the use of molecular cloning strategies to dissect the development of the human heavy chain repertoire during fetal life. Because the extent of VH region polymorphism in the outbred human population is undefined, we have chosen to analyze individual fetal samples.Fetal B lymphopoiesis begins in the liver, with pre-B cells first detectable by 8 weeks of gestation (10). We isolated fetal liver mononuclear cells, which are rich in B-cell precursors, and generated oligo(dT)-primed cDNA libraries. We previously reported evidence of preferential usage of VH, DH, and JH gene segments by cloning and sequencing 1...

The VλJλ Repertoire in Human Fetal Spleen: Evidence for Positive Selection and Extensive Receptor Editing

“…Three distinct characteristics of the fetal repertoire have been described, namely restriction in Ag specificities, low avidity, and multireactivity to self Ags. Previous reports have indicated that restrictions in Ag specificities are achieved by limited and preferential usage of certain V H and V gene segments (12,28). Preferential gene use reflected the proximity of gene segments in chromosomal position (8,9,12).…”

“…Analysis of V H and V gene expression in different stages of development, in both humans and mice, has suggested developmentally controlled nonrandom use of V(D)J genes and unique patterns of junctional diversity (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17). With better understanding of BCR signaling, recent studies have provided direct evidence that bias in the Ab repertoire is a result of selection mediated through pBCR and BCR (18 -20).…”

Characterization of the immunoglobulin light chain variable region gene expressed in multiple myeloma

“…In the rearrangement of the IgH gene, the usage of J H segments revealed a developmental stage-specific trend. [7][8][9][10][11][12][13] At the earliest stage of B cell development, the initial D-J H rearrangements predominantly occur between D H Q52 and J H -1 segments which are located close to each other. 53 During B cell development, a second or a third D-J H joining might occur, then the more 5ЈD segments and more 3ЈJ H segments would join at a later stage.…”

“…6 Studies on IgH variable region gene sequences at various stages of development have revealed stage-specific trends in the usage of V H , D, and J H segments, the degree of N nucleotide addition, and the rate of somatic mutations. [7][8][9][10][11][12][13] However, little is known of the organization and diversification of the IgL variable region gene on -chain. On the other hand, multiple myeloma (MM) has a variety of clinical features relating to clinical stage, prognosis and complication.…”

Oligoclonal dominance of immunglobulin VH3 rearrangements following allogeneic bone marrow transplantation

“…8 Furthermore, the post-BMT immune deficiency may be explained by a restricted usage of the Ig genes, as seen in fetal and neonatal life. [9][10][11] The genes encoding the variable and constant region of the Ig heavy chain (IgH) are located on chromosome 14q. Variability in the antigen binding site is obtained by recombination of one diversity (D) gene to one junctional (JH) gene, and a second recombination of this complex to a variable (VH) gene segment.…”