Mutation, selection, and memory in B lymphocytes of exothermic vertebrates

Hsu, Ellen

doi:10.1111/j.1600-065x.1998.tb01426.x

Cited by 85 publications

(65 citation statements)

References 96 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Although most results indicate that affinity maturation in ectothermic vertebrates is poor (20,21), two studies in nurse sharks found evidence that affinity maturation of monomeric IgM occurs after immunization (22,23). It is thought that IgNAR (and monomeric IgM) production is a T-dependent response that provides the specificity of the shark humoral response (23), but, because of its apparent sensitivity to degradation in vitro (H.D.…”

Section: First Molecular and Biochemical Analysis Of In Vivo Affinitymentioning

confidence: 99%

First molecular and biochemical analysis ofin vivoaffinity maturation in an ectothermic vertebrate

Dooley

Stanfield

Brady

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

The cartilaginous fish are the oldest phylogenetic group in which Igs have been found. Sharks produce a unique Ig isotype, IgNAR, a heavy-chain homodimer that does not associate with light chains. Instead, the variable (V) regions of IgNAR bind antigen as soluble single domains. Our group has shown that IgNAR plays an integral part in the humoral response of nurse sharks ( Ginglymostoma cirratum ) upon antigen challenge. Here, we generated phage-displayed libraries of IgNAR V regions from an immunized animal and found a family of clones derived from the same rearrangement event but differentially mutated during expansion. Because of the cluster organization of shark Ig genes and the paucicopy nature of IgNAR, we were able to construct the putative ancestor of this family. By studying mutations in the context of clone affinities, we found evidence that affinity maturation occurs for this isotype. Subsequently, we were able to identify mutations important in the affinity improvement of this family. Because the family clones were all obtained after immunization, they provide insight into the in vivo maturation mechanisms, in general, and for single-domain antibody fragments.

show abstract

Section: First Molecular and Biochemical Analysis Of In Vivo Affinitymentioning

confidence: 99%

First molecular and biochemical analysis ofin vivoaffinity maturation in an ectothermic vertebrate

Dooley

Stanfield

Brady

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…Compared with adults, however, larvae have a lower V region diversity, and reduced class switch and Ab affinity (14,19,20). We asked therefore whether this somewhat immature state of B cell maturation was reflected in the expression pattern of XlAID.…”

Section: Figurementioning

confidence: 99%

“…For example, the affinity of IgY Ab against DNP-KLH proteins increases by Ͻ10 times during a humoral response in contrast to more than a 10,000-fold affinity increase in mammals (19). Sequence analysis of VH1 gene family during Ab response to DNP-KLH has revealed that the rate of somatic mutations is not very different between Xenopus and mice (20).…”

mentioning

confidence: 99%

Localization and Differential Expression of Activation-Induced Cytidine Deaminase in the Amphibian Xenopus upon Antigen Stimulation and during Early Development

Marr

Morales²,

Bottaro

et al. 2007

The Journal of Immunology

View full text Add to dashboard Cite

As in mammals, B cell maturation in the amphibian Xenopus involves somatic hypermutation (SHM) and class switch recombination to diversify the B cell receptor repertoire in response to Ag stimulation. Unlike mammals, however, the resulting increase in Ab affinity is poor in Xenopus, which is possibly related to the absence of germinal centers and a suboptimal selection mechanism of SHM. In mammals, both SHM and class switch recombination are mediated by the activation-induced cytidine deaminase enzyme and under Ag-dependent regulation. Given its evolutionary conservation in jawed vertebrates, we used activation-induced cytidine deaminase as a marker to monitor and localize B cell maturation in Xenopus upon immune responses and during early development. In adult, Xenopus laevis AID (XlAID) was detected mainly in the spleen, where cells expressing XlAID were preferentially distributed in follicular B cell zones, although some XlAID+ cells were also found in the red pulp. XlAID was markedly up-regulated in the spleen with different kinetics upon bacterial stimulation and viral infection. However, during secondary anti-viral response XlAID was also noticeably expressed by PBLs, suggesting that XlAID remains active in a subset of circulating B cells. During ontogeny, XlAID expression was detected as early as 5 days postfertilization in liver before the first fully differentiated B cells appear. Concomitant with appearance of mature B cells XlAID was up-regulated upon bacterial stimulation or viral infection at later larval stages. This study highlights the conserved involvement of XlAID during Ag-dependent B cell responses in Xenopus but also suggests another role in B cell differentiation earlier in ontogeny.

show abstract

“…although not yet efficient [1,2]. Therefore, the innate immune system plays a fundamental role in the amphibia host response.…”

mentioning

confidence: 99%

Involvement of Rel factors in the expression of antimicrobial peptide genes in amphibia

Miele¹,

Bjorklund²,

Barra³

et al. 2001

Eur J Biochem

View full text Add to dashboard Cite

Genes coding for antimicrobial peptides in amphibia reveal a remarkably high number of structural motifs for response elements, previously identified in the genes of insect antimicrobial peptides and in those of the mammalian acute phase response. This study focuses on the functional analysis of the bombinin gene promoter in a Drosophila blood cell line, and the identification of kB-binding factors in skin secretions of the frog Bombina orientalis. Transfection experiments demonstrated that the bombinin gene promoter was activated in a lipopolysaccharidedependent manner, and that insect Rel factors target specific sequences in the amphibian gene promoter. After bathing frogs in bacteria, their skin secretions contained kB-specific binding complexes, indicating that Rel factors are crucial components in the response against gramnegative bacteria in this species. These results suggest that a common ancestral control mechanism governs the expression of the first line host-defence from insects to vertebrates.

show abstract

Mutation, selection, and memory in B lymphocytes of exothermic vertebrates

Cited by 85 publications

References 96 publications

First molecular and biochemical analysis ofin vivoaffinity maturation in an ectothermic vertebrate

First molecular and biochemical analysis ofin vivoaffinity maturation in an ectothermic vertebrate

Localization and Differential Expression of Activation-Induced Cytidine Deaminase in the Amphibian Xenopus upon Antigen Stimulation and during Early Development

Involvement of Rel factors in the expression of antimicrobial peptide genes in amphibia

Contact Info

Product

Resources

About