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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↗

USGS2014

Channel catfish (Ictalurus punctatus) leukocytes express estrogen receptor isoforms ERα and ERβ2 and are functionally modulated by estrogens

Estrogens are recognized as modulators of immune responses in mammals and teleosts. While it is known that the effects of estrogens are mediated via leukocyte-specific estrogen receptors (ERs) in humans and mice, leucocyte-specific estrogen receptor expression and the effects of estrogens on this cell population is less explored and poorly understood in teleosts. Here in, we verify that channel catfish ( Ictalurus punctaus ) leukocytes express ERα and ERβ2. Transcripts of these isoforms were detected in tissue-associated leukocyte populations by PCR, but ERβ2 was rarely detected in PBLs. Expression of these receptors was temporally regulated in PBLs following polyclonal activation by concanavalin A, lipopolysaccharide or alloantigen based on evaluation by quantitative and end-point PCR. Examination of long-term leukocyte cell lines demonstrated that these receptors are differentially expressed depending on leukocyte lineage and phenotype. Expression of ERs was also temporally dynamic in some leukocyte lineages and may reflect stage of cell maturity. Estrogens affect the responsiveness of channel catfish peripheral blood leukocytes (PBLs) to mitogens in vitro . Similarly, bactericidal activity and phorbol 12-myristate 13-acetate induced respiratory burst was modulated by 17β-estradiol. These actions were blocked by the pure ER antagonist ICI 182780 indicating that response is, in part, mediated via ERα. In summary, estrogen receptors are expressed in channel catfish leukocytes and participate in the regulation of the immune response. This is the first time leukocyte lineage expression has been reported in teleost cell lines.

Fish & Shellfish Immunology↗