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Results for “Developmental and Comparative Immunology”

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26 records · Page 2Linked to original sources

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↗

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↗

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↗

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↗

Developmental toxicity in white leghorn chickens following in ovo exposure to perfluorooctane sulfonate (PFOS)

Studies show that perfluorinated compounds cause various toxicological effects; nevertheless, effects on immune function and developmental endpoints have not been addressed at length. This study examined the effects of perfluorooctane sulfonate (PFOS) in white leghorn hatchlings on various developmental, immunological, and clinical health parameters. In addition, serum PFOS concentrations were determined by LC/MS/MS. Embryonic day (ED) 0 eggs were injected with either safflower oil/10% DMSO (control, 0 mg/kg egg wt) or PFOS in safflower oil/10% DMSO at 1, 2.5, or 5 mg/kg egg wt, and the chicks were grown to post-hatch day (PHD) 14. Treatment with PFOS did not affect hatch rate. Following in ovo exposure chicks exhibited increases in spleen mass at all treatment levels, in liver mass at 2.5 and 5 mg/kg egg wt, and in body length (crown-rump length) at the 5 mg/kg treatment. Right wings were shorter in all treatments compared to control. Increases in the frequency of brain asymmetry were evident in all treatment groups. SRBC-specific immunoglobulin (IgM and IgY combined) titers were decreased significantly at all treatment levels, while plasma lysozyme activity was increased at all treatment levels. The PHA skin test response decreased in relation to increasing PFOS dose. Serum concentrations where significant immunological, morphological, and neurological effects were observed at the lowest dose (1 mg/kg egg wt) averaged 154 ng PFOS/g serum. These concentrations fall within environmental ranges reported in blood samples from wild caught avian species; thereby, verifying that the environmental egg concentrations used for the injections do indeed relate to serum levels in hatchlings that are also environmentally relevant. These data indicate that immune alterations and brain asymmetry can occur in birds following in ovo exposure to environmentally relevant concentrations of PFOS and demonstrates the need for further research on the developmental effects of perfluorinated compounds in various species. ?? 2009 Elsevier Inc.

Reproductive Toxicology↗