Biomedical subjects

Christopher J Secombes

Publications and source records attributed to Christopher J Secombes.

39 records · Page 3Linked to original sources

PubMed2002

Identification and analysis of an interleukin 8-like molecule in rainbow trout Oncorhynchus mykiss.

An interleukin 8 (IL-8) homologue has been identified in the rainbow trout Oncorhynchus mykiss. The transcript contains an open reading frame of 294 nucleotides that translates into a 97 amino acid putative peptide, with 5' and 3' untranslated regions (UTR) of 171 and 453 nucleotides, respectively. As with previously sequenced lamprey and flounder genes, the trout amino acid sequence lacks the typical ELR motif upstream of the first pair of cysteines, where DLR is present. The trout IL-8 gene contains four exons divided by three short introns of 341, 247 and 292bp, and occupies 1824bp of genomic DNA. RT-PCR reveals a low level constitutive expression of the IL-8 homologue in many tissues, including spleen, heart, liver, head kidney and gill. Expression was not detectable in the brain. Whilst no apparent affect of lipopolysaccharide (LPS) on IL-8 expression was observed in vivo, stimulation of a trout macrophage cell line (RTS-11) with either LPS or poly I:C did result in clear up-regulation of IL-8 expression, detectable by RT-PCR and Northern blot analysis.

Amino Acid Sequence↗

PubMed2002

Immunostimulation in the rainbow trout (Oncorhynchus mykiss) following intraperitoneal administration of Ergosan.

The present work provides information concerning the immunostimulatory activity of Ergosan, an algal based product, injected intraperitoneally in the rainbow trout (Oncorhynchus mykiss). Ergosan is composed of 0.002% unspecified plant extract, 1% alginic acid from Laminaria digitata, and 98.998% algal based carrier. Migration of leucocytes into the peritoneal cavity was stimulated at doses > or =1 mg ml(-1). A single dose of 1mg significantly augmented the proportion of neutrophils, degree of phagocytosis, respiratory burst activity and expression of interleukin-1beta (IL-1beta), interleukin-8 (IL-8) and one of the two known isoforms of trout tumour necrosis factor-alpha (TNF2) in peritoneal leucocytes at 1 day post-injection. Humoral immune parameters were less responsive to intraperitoneal Ergosan administration, with complement stimulation only evident in the 1mg treated group at 2 days post-injection. Antiprotease and lysozyme activity were unaffected by Ergosan over a 7-day time period at the doses examined.

Adjuvants, Immunologic↗

PubMedDate not supplied

A CXC chemokine sequence isolated from the rainbow trout Oncorhynchus mykiss resembles the closely related interferon-gamma-inducible chemokines CXCL9, CXCL10 and CXCL11.

A sequence encoding a CXC - type chemokine from rainbow trout was found to most resemble members of the CXCL9/CXCL10/CXCL11 sub-family. In mammals, all 3 chemokines are regulated by IFN-gamma and are chemotactic for activated T lymphocytes. The trout chemokine (gammaIP1), with a message of 787 nucleotides, contains 100 amino acids in a typical non-ELR CXC chemokine arrangement. A second sequence (gammaIP2), with 6 nucleotide differences in the coding region when compared to the first, was also identified although it is not known whether this is a second functional gene or a second allele. The gene is separated onto 4 exons, and the introns intervene in conserved positions according to the mammalian equivalents. The sequence encoded by the second exon shares the highest amino acid identity (37%) with CXCL10, with lower values of identity to other CXC chemokines (17-31%). Furthermore, phylogenetic analysis groups the trout chemokine with mammalian CXCL9, CXCL10 and CXCL11 peptides. Constitutive expression of gammaIP is seen in trout gill and low level expression in spleen, head kidney and liver. In RTS-11 cells, gammaIP expression can be induced with poly I:C, but not by LPS, suggesting virus-mediated regulation of gammaIP. Intraperitoneal injection of recombinant trout TNF-alpha caused elevation in gammaIP mRNA levels in trout head kidney.

Amino Acid Sequence↗