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Results for “Developmental and Comparative Immunology”

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At least 19 recordsLinked to original sources
USGS2011

Fish T cells: recent advances through genomics

This brief review is intended to provide a concise overview of the current literature concerning T cells, advances in identifying distinct T cell functional subsets, and in distinguishing effector cells from memory cells. We compare and contrast a wealth of recent progress made in T cell immunology of teleost, elasmobranch, and agnathan fish, to knowledge derived from mammalian T cell studies. From genome studies, fish clearly have most components associated with T cell function and we can speculate on the presence of putative T cell subsets, and the ability to detect their differentiation to form memory cells. Some recombinant proteins for T cell associated cytokines and antibodies for T cell surface receptors have been generated that will facilitate studying the functional roles of teleost T cells during immune responses. Although there is still a long way to go, major advances have occurred in recent years for investigating T cell responses, thus phenotypic and functional characterization is on the near horizon.

Developmental and Comparative Immunology↗
USGS2004

Potential involvement of rainbow trout thrombocytes in immune functions: a study using a panel of monoclonal antibodies and RT-PCR

The functional relationship between fish and mammalian thrombocytes is relatively unknown. In this study, a panel of monoclonal antibodies (mAbs) was used to investigate the functional properties of rainbow trout thrombocytes. The mAbs recognize cell-surface molecules on thrombocytes with molecular weights ranging from 17 to 160 kDa. Flow cytometric and immuno-electron microscopic analyses demonstrate that these molecules are expressed at different levels and that surface expression increased upon activation with bovine collagen. Two of these cell-surface molecules (17 and 21 kDa) were directly involved in collagen-induced aggregation of thrombocytes since aggregation was blocked upon pre-treatment with mAbs that recognize the two surface markers. Interestingly, the percentage of thrombocytes in blood increased after stimulation using different antigens. The transcriptional profile of trout thrombocytes was then examined after immuno-magnetic enrichment using the described mAbs to assess potential roles of trout thrombocytes in immune functions. Trout thrombocytes express components of the MHC class Ia pathway, IL1β, TNFα, TGFβ, the interleukin receptor common γ chain as well as CXC and CC chemokines. MHC class IIB and TNFα were expressed at low levels in resting thrombocytes. No evidence was found for the expression of TCRαβ, Ig heavy chain, CD8α or CK1 mRNA. Taken together, these results suggest that rainbow trout thrombocytes express molecules involved in activation, aggregation and genes encoding proteins, that are involved in antigen presentation and immune regulation.

Developmental and Comparative Immunology↗
USGS2007

Evolutionary history of the ABCB2 genomic region in teleosts

Gene duplication, silencing and translocation have all been implicated in shaping the unique genomic architecture of the teleost MH regions. Previously, we demonstrated that trout possess five unlinked regions encoding MH genes. One of these regions harbors ABCB2 which in all other vertebrate classes is found in the MHC class II region. In this study, we sequenced a BAC contig for the trout ABCB2 region. Analysis of this region revealed the presence of genes homologous to those located in the human class II (ABCB2, BRD2, ??DAA), extended class II (RGL2, PHF1, SYGP1) and class III (PBX2, Notch-L) regions. The organization and syntenic relationships of this region were then compared to similar regions in humans, Tetraodon and zebrafish to learn more about the evolutionary history of this region. Our analysis indicates that this region was generated during the teleost-specific duplication event while also providing insight about potential MH paralogous regions in teleosts. ?? 2006 Elsevier Ltd. All rights reserved.

Developmental and Comparative Immunology↗
USGS2011

Sensing disease and danger: A survey of vertebrate PRRs and their origins

A key facet of the innate immune response lays in its ability to recognize and respond to invading microorganisms and cellular disturbances. Through the use of germ-line encoded PRRs, the innate immune system is capable of detecting invariant pathogen motifs termed pathogen-associated molecular patterns (PAMPS) that are distinct from host encoded proteins or products released from dying cells, which are known as damage-associated molecular patterns (DAMPs). PAMPs and DAMPs include both protein and nucleic acids for the detection and response to pathogens and metabolic "danger" signals. This is by far one of the most active areas of research as recent studies have shown retinoic acid inducible gene 1 (RIG1)-like receptors (RLRs), the nucleotide-binding domain, leucine-rich repeat containing proteins (NLRs) and Toll-like receptors (TLRs) and the recently described AIM-like receptors (ALRs) are responsible for initiating interferon production or the assembly and activation of the inflammasome, ultimately resulting in the release of bioactive IL-1 family members. Overall, the vertebrate PRR recognition machinery consists of seven domains (e.g., Death, NACHT, CARD, TIR, LRR, PYD, helicase), most of which can be traced to the very origins of the deuterostomes. This review is intended to provide an overview of the basic components that are used by vertebrates to detect and respond to pathogens, with an emphasis on these receptors in fish as well as a brief note on their likely origins.

Developmental and Comparative Immunology↗
USGS2013

Expression kinetics of key genes in the early innate immune response to Great Lakes viral hemorrhagic septicemia virus IVb infection in yellow perch ( Perca flavescens )

The recently discovered strain of viral hemorrhagic septicemia virus, VHSV-IVb, represents an example of the introduction of an extremely pathogenic rhabdovirus capable of infecting a wide variety of new fish species in a new host-environment. The goal of the present study was to delineate the expression kinetics of key genes in the innate immune response relative to the very early stages of VHSV-IVb infection using the yellow perch ( Perca flavescens ) as a model. Administration of VHSV-IVb by IP-injection into juvenile yellow perch resulted in 84% cumulative mortality, indicating their high susceptibility to this disease. In fish sampled in the very early stages of infection, a significant up-regulation of Mx gene expression in the liver, as well as IL-1β and SAA activation in the head kidney, spleen, and liver was directly correlated to viral load. The potential down-regulation of Mx in the hematopoietic tissues, head kidney and spleen, may represent a strategy utilized by the virus to increase replication.

Developmental and Comparative Immunology↗
USGS2017

The Florida manatee (Trichechus manatus latirostris) immunoglobulin heavy chain suggests the importance of clan III variable segments in repertoire diversity

Manatees are a vulnerable, charismatic sentinel species from the evolutionarily divergent Afrotheria. Manatee health and resistance to infectious disease is of great concern to conservation groups, but little is known about their immune system. To develop manatee-specific tools for monitoring health, we first must have a general knowledge of how the immunoglobulin heavy (IgH) chain locus is organized and transcriptionally expressed. Using the genomic scaffolds of the Florida manatee ( Trichechus manatus latirostris ), we characterized the potential IgH segmental diversity and constant region isotypic diversity and performed the first Afrotherian repertoire analysis. The Florida manatee has low V(D)J combinatorial diversity (3744 potential combinations) and few constant region isotypes. They also lack clan III V segments, which may have caused reduced VH segment numbers. However, we found productive somatic hypermutation concentrated in the complementarity determining regions. In conclusion, manatees have limited IGHV clan and combinatorial diversity. This suggests that clan III V segments are essential for maintaining IgH locus diversity.

Developmental and Comparative Immunology↗
USGS2017

Evolutionary dynamics of an expressed MHC class IIβ locus in the Ranidae (Anura) uncovered by genome walking and high-throughput amplicon sequencing

The Major Histocompatibility Complex (MHC) is a genomic region encoding immune loci that are important and frequently used markers in studies of adaptive genetic variation and disease resistance. Given the primary role of infectious diseases in contributing to global amphibian declines, we characterized the hypervariable exon 2 and flanking introns of the MHC Class IIβ chain for 17 species of frogs in the Ranidae, a speciose and cosmopolitan family facing widespread pathogen infections and declines. We find high levels of genetic variation concentrated in the Peptide Binding Region (PBR) of the exon. Ten codons are under positive selection, nine of which are located in the mammal-defined PBR. We hypothesize that the tenth codon (residue 21) is an amphibian-specific PBR site that may be important in disease resistance. Trans-species and trans-generic polymorphisms are evident from exon-based genealogies, and co-phylogenetic analyses between intron, exon and mitochondrial based reconstructions reveal incongruent topologies, likely due to different locus histories. We developed two sets of barcoded adapters that reliably amplify a single and likely functional locus in all screened species using both 454 and Illumina based sequencing methods. These primers provide a resource for multiplexing and directly sequencing hundreds of samples in a single sequencing run, avoiding the labour and chimeric sequences associated with cloning, and enabling MHC population genetic analyses. Although the primers are currently limited to the 17 species we tested, these sequences and protocols provide a useful genetic resource and can serve as a starting point for future disease, adaptation and conservation studies across a range of anuran taxa.

Developmental and Comparative Immunology↗
USGS2018

The Florida manatee (Trichechus manatus latirostris) T cell receptor loci exhibit V subgroup synteny and chain-specific evolution

The Florida manatee ( Trichechus manatus latirostris ) has limited diversity in the immunoglobulin heavy chain. We therefore investigated the antigen receptor loci of the other arm of the adaptive immune system: the T cell receptor. M anatees are the first species from Afrotheria, a basal eutherian superorder, to have an in-depth characterization of all T cell receptor loci. By annotating the genome and expressed transcripts, we found that each chain has distinct features that correlates to their individual functions. The genomic organization also plays a role in modulating sequence conservation between species. There were extensive V subgroup synteny blocks in the TRA and TRB l oci between T. m. latirostris and human. Increased genomic locus complexity correlated to increased locus synteny. We also identified evidence for a VHD pseudogene for the first time in a eutherian mammal. These findings emphasize the value of including species within this basal eutherian radiation in comparative studies.

Developmental and Comparative Immunology↗
USGS2019

Characterization of immunoglobulin light chain utilization and variable family diversity in rainbow trout

This study characterizes immunoglobulin light chain (IgL) expression and variable family usage in rainbow trout. IgL transcripts were generated by 5’ RACE from both immune and TNP-KLH immunized fish. Phylogenetic analysis revealed that the IgL variable regions clustered into seven different families: three kappa families (two newly described in this study), three sigma families, and a single lambda family. IgL1 and IgL3 transcripts expressing identical variable regions were identified and genomic analysis revealed that the two isotypes are co-localized on chromosomes 7, 15, 18, and 21 allowing for potential rearrangement between clusters. Fish were immunized with TNP-KLH (n = 5) and percent expression of IgL1, IgL2, IgL3, and IgL4 measured by qRT-PCR from immune tissues and magnetically sorted TNP-specific lymphocyte populations. In all samples IgL1 constituted 80–95% of the transcripts. The percentage of anti-TNP specific IgL1 transcripts was measured in naïve, unsorted, and TNP-specific cell populations of TNP-KLH fish (n = 3) and found to be significantly higher in the TNP positive cell population (21%) compared to the naïve population (1%; p = 0.02) suggesting that there is a selection of TNP specific IgL sequences.

Developmental and Comparative Immunology↗
USGS2020

Genomic architecture and repertoire of the rainbow trout immunoglobulin light chain genes

The genomic loci encoding the four immunoglobulin light chains (IgL1, IgL2, IgL3, and IgL4) in the Swanson trout genome assembly were annotated in order to provide a measurement of the potential IgL repertoire. IgL1 and IgL3 gene segments are co-localized on chromosomes 21, 18, 15, and 7 while IgL2 and IgL4 were found on chromosomes 13 and 17, respectively. In total, 48 constant (C L ), 87 variable (V L ), and 59 joining (J L ) productive genes are described. Pairwise alignment of the V L segments revealed that they belong to nine different families, three of which (kappa IV, V, and VI) are described for the first time in this study. V L and C L sequences on chromosome 15 and 21 and those on chromosomes 7 and 18 clustered together in phylogenetic analysis. PCR was used to examine IgL C L and V L genes in 9 lines of rainbow trout. IgL4 in the Hot Creek and Golden trout lines was missing 42 nucleotides resulting in a loss of 14 amino acids. The sigma IV variable family was completely absent from the Swanson, Arlee, Hot Creek, and wild type lines and silenced in the Skamania line with the addition of 176 bp mini-satellite insert. Similarly, the Whale Rock, Arlee, and wild type lines were all found to encode two sigma II products, a functional 252 bp product and a larger 425 bp product that contained a 172 bp insert. Results from this study indicate that there are genomic differences in IgL repertoire between different lines of trout that could affect humoral immune responses post vaccination and during disease.

Developmental and Comparative Immunology↗
USGS2022

Novel insights on aquatic mammal MHC evolution: Evidence from manatee DQB diversity

The low diversity in marine mammal major histocompatibility complex (MHC) appears to support the hypothesis of reduced pathogen selective pressure in aquatic systems compared to terrestrial environments. However, the lack of characterization of the aquatic and evolutionarily distant Sirenia precludes drawing more generalized conclusions. Therefore, we aimed to characterize the MHC DQB diversity of two manatee species and compare it with those reported for marine mammals. Our results identified 12 and 6 alleles in T. inunguis and T. manatus , respectively. Alleles show high rates of nonsynonymous substitutions, suggesting loci are evolving under positive selection. Among aquatic mammals, Pinnipeda DQB had smaller numbers of alleles, higher synonymous substitution rate, and a dN/dS ratio closer to 1, suggesting it may be evolving under more relaxed selection compared to fully aquatic mammals. This contradicts one of the predictions of the hypothesis that aquatic environments impose reduced pathogen pressure to mammalian immune system. These results suggest that the unique evolutionary trajectories of mammalian MHC may impose challenges in drawing ecoevolutionary conclusions from comparisons across distant vertebrate lineages.

Florida↗