Regulation of antibody synthesis in the X‐irradiated Mexican axolotl

Charlemagne, Jacques

doi:10.1002/eji.1830110909

Cited by 9 publications

(4 citation statements)

References 11 publications

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“…Mortality events due to ATV are more significant among larvae in natural tiger salamander populations, however metamorphosed adult tiger salamanders are more susceptible than larvae to ATV infection in the lab [ 18 ]. It is well established that Mexican axolotls have a less complicated immune system and never develop the type of mature immune response typical of amniote vertebrates [ 21 - 29 , 52 ]. We did not observe any gene expression changes that would indicate proliferative leukocyte responses in axolotl spleen.…”

Section: Discussionmentioning

confidence: 99%

“…Relative to other vertebrate models, the axolotl immune response has been described as immunodeficient [ 21 , 22 ]. There are several reasons for this characterization, including: production of only two immunoglobulin (Ig) classes, only one of which regulates the humoral response and neither of which is anamnestic [ 23 , 24 ]; no response to soluble antigens [ 25 ]; poor mixed lymphocyte reactions [ 26 , 27 ]; and lack of cellular cooperation during the humoral immune response as indicated by enhanced humoral immunity following thymectomy or X-ray irradiation [ 28 , 29 ]. Weak immune responses are known for salamanders in general, and the Mexican axolotl and related tiger salamanders are especially susceptible to ATV infections with high observed mortality rates both in the laboratory and in the field.…”

Section: Introductionmentioning

confidence: 99%

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Transcriptional response of Mexican axolotls to Ambystoma tigrinum virus (ATV) infection

et al. 2008

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BackgroundVery little is known about the immunological responses of amphibians to pathogens that are causing global population declines. We used a custom microarray gene chip to characterize gene expression responses of axolotls (Ambystoma mexicanum) to an emerging viral pathogen, Ambystoma tigrinum virus (ATV).ResultAt 0, 24, 72, and 144 hours post-infection, spleen and lung samples were removed for estimation of host mRNA abundance and viral load. A total of 158 up-regulated and 105 down-regulated genes were identified across all time points using statistical and fold level criteria. The presumptive functions of these genes suggest a robust innate immune and antiviral gene expression response is initiated by A. mexicanum as early as 24 hours after ATV infection. At 24 hours, we observed transcript abundance changes for genes that are associated with phagocytosis and cytokine signaling, complement, and other general immune and defense responses. By 144 hours, we observed gene expression changes indicating host-mediated cell death, inflammation, and cytotoxicity.ConclusionAlthough A. mexicanum appears to mount a robust innate immune response, we did not observe gene expression changes indicative of lymphocyte proliferation in the spleen, which is associated with clearance of Frog 3 iridovirus in adult Xenopus. We speculate that ATV may be especially lethal to A. mexicanum and related tiger salamanders because they lack proliferative lymphocyte responses that are needed to clear highly virulent iridoviruses. Genes identified from this study provide important new resources to investigate ATV disease pathology and host-pathogen dynamics in natural populations.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Transcriptional response of Mexican axolotls to Ambystoma tigrinum virus (ATV) infection

et al. 2008

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“…Nevertheless, CSR and SHM still occur in Xenopus (Flajnik 2018). Ambystoma sp ., but not other salamanders and not anuran amphibians are particularly vulnerable to certain viral infections (Charlemagne and Tournefier 1977; Charlemagne 1979, 1981; Cotter et al 2008; Liu et al 2014; Fonte et al 2015). The divergence between anurans and caudate is estimated to occur 292 my ago (Pyron 2011).…”

Section: Introductionmentioning

confidence: 99%

Subfunctionalization and constrained size of the immunoglobulinlociinAmbystoma mexicanum

Martínez-Barnetche

Godoy-Lozano

Remy-Hernández

et al. 2022

Preprint

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Background: The axolotl, Ambystoma mexicanum is a unique biological model for complete tissue regeneration. Is a neotenic endangered species and is highly susceptible to environmental stress, including infectious disease. In contrast to other amphibians, the axolotl is particularly vulnerable to certain viral infections. Like other salamanders, the axolotl genome is one of the largest (32 Gb) and the impact of genome size on Ig loci architecture is unknown. To better understand the immune response in axolotl, we aimed to characterize the immunoglobulin loci of A. mexicanum and compare it with other model tetrapods. Methods: The most recently published genome sequence of A. mexicanum (V6) was used for alignment-based annotation and manual curation using previously described axolotl Ig sequences or reference sequences from other tetrapods. Gene models were further curated using A. mexicanum spleen RNA-seq data. Human reference genomes, Xenopus tropicalis, and Danio rerio (zebrafish) were used for comparison. Results: Canonical A. mexicanum Heavy chain (IGH), lambda (IGL), sigma (IGS) and Surrogate light chain (SLC) loci were identified. No kappa locus was found. More than half of the IGHV genes and the IGHF gene are pseudogenes, there are no clan I IGHV genes and CDRH3 diversity is restricted. Although the IGH locus size is proportional to genome size, we found local size restriction in the IGHM gene and in the V gene intergenic distances. In addition, there were V genes with abnormally large V-intron sizes, which correlated with loss of gene functionality. Conclusion: The A. mexicanum immunoglobulin loci share the same general genome architecture as most studied tetrapods. Consistent with its large genome, Ig loci are larger; however, local size restrictions indicate evolutionary constraints likely to be imposed by high transcriptional demand of certain Ig genes, as well as the V(D)J recombination over very long genomic distance ranges. The A. mexicanum has undergone an extensive process of pseudogenization which partially explains a reduced potential repertoire diversity that may contribute to its impaired antibody response.

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“…Unlike in mammals, early thymectomy has no effect on the humoral response but enhances antibody production to erythrocytes or hapten-modified erythrocyte antigens [6,7]. A similar effect is observed when adult animals are thymectomized [7], treated with hydrocortisone [8] or submitted to low-dose irradiation [9]. The use of lactate dehydrogenase isoenzymes as a tool for T and B-like lymphocytes markers was also investigated [10].…”

Section: Introductionmentioning

confidence: 99%

High levels of HMG1‐2 protein expression in the cytoplasm and nucleus of hydrocortisone sensitive amphibian thymocytes

Guillet

Tournefier

Denoulet

et al. 1990

Biology of the Cell

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A major 26 kDa protein was identified in the cytoplasmic and nuclear compartments of axolotl thymocytes. A polyclonal antiserum was produced against the denatured form of this protein. High levels of 26 kDa were expressed by hydrocortisone-sensitive lymphocytes which represent a major thymocyte subpopulation in young animals. However, no further expression of the 26 kDa protein was observed in involuted thymus of adult animals nor in thymus of young artificially metamorphosed axolotls. The 26 kDa was never expressed by splenic and blood peripheral lymphocytes at any stage of development. Partial N-terminal amino acid sequence and amino acid composition demonstrate that the 26 kDa polypeptide is strongly homologous to HMG1-2 proteins, the most abundant members of the high mobility group (HMG) non-histone chromosomal proteins. HMG1-2 are thought to be involved in the organization of chromatin structure, as well as in the stability, replication and transcription of DNA. It was confirmed that the 26 kDa axolotl polypeptide is recognized by a well characterized rabbit antiserum to rat HMG1-2 proteins.

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Regulation of antibody synthesis in the X‐irradiated Mexican axolotl

Cited by 9 publications

References 11 publications

Transcriptional response of Mexican axolotls to Ambystoma tigrinum virus (ATV) infection

Transcriptional response of Mexican axolotls to Ambystoma tigrinum virus (ATV) infection

Subfunctionalization and constrained size of the immunoglobulinlociinAmbystoma mexicanum

High levels of HMG1‐2 protein expression in the cytoplasm and nucleus of hydrocortisone sensitive amphibian thymocytes

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