Allergy to fish parvalbumins: studies on the cross-reactivity of allergens from 9 commonly consumed fish.

Background: Fish-hypersensitive patients can probably tolerate some fish species while being allergic to others.

Objective: To determine the allergenic cross-reactivity between 9 commonly edible fish: cod, salmon, pollack, mackerel, tuna, herring, wolffish, halibut, and flounder.

Methods: Sera from 10 patients allergic to fish and rabbit antisera against 3 parvalbumins (Gad c 1, Sal s 1, and The c 1) were used.

Sensitive and specific detection of Salmonid alphavirus using real-time PCR (TaqMan).

Pancreas disease is responsible for major economic losses in the European salmonid farming industry. It was previously believed that a single subtype (salmon pancreas disease virus) of the virus species Salmonid alphavirus (SAV) was responsible for all outbreaks of pancreas disease in the UK and Norway. However, the recent discovery that pancreas disease in Norway is caused by a new and distinct subtype of salmonid alphavirus, exclusively found in Norway, has advocated the need for better diagnostic tools.

Characterization of parvalbumin, the major allergen in Alaska pollack, and comparison with codfish Allergen M.

Increased fish consumption has led to frequent reporting of fish allergy and adverse reactions. Alaska pollack (Theragra chalcogramma) is a globally important commercial fish species, belonging to the Gadidae family. This family of fish also includes cod whose parvalbumin, Allergen M (Gad c 1), has been thoroughly studied and considered as a reference to sensitization in fish allergy.

Infectious salmon anemia virus (ISAV) genomic segment 3 encodes the viral nucleoprotein (NP), an RNA-binding protein with two monopartite nuclear localization signals (NLS).

Infectious salmon anemia virus (ISAV) is the type species of the genus Isavirus belonging to the Orthomyxoviridae, and causes serious disease in Atlantic salmon (Salmo salar). This study presents the expression and functional analysis of the ISAV genome segment 3, and provides further evidence that it encodes the viral nucleoprotein (NP). The encoded protein was expressed in a baculovirus system, and Western blot analysis showed that it corresponds to the 66-71 kDa structural protein previously found in purified ISAV preparations.

Structure and organization of the T cell receptor alpha chain genes in Atlantic salmon.

A cDNA fragment of the T cell receptor (TCR) alpha chain mRNA in Atlantic salmon (Salmo salar) was amplified by PCR and used as a probe to isolate a full-length clone from a leukocyte cDNA library. Additionally, a genomic lambda clone comprising the TCR alpha chain constant region (Calpha) gene and flanking regions was isolated and partially sequenced. The Calpha gene consists of three exons corresponding to the immunoglobulin (Ig) domain, the hinge region and the transmembrane peptide/cytoplasmatic tail, and two exons corresponding to the untranslated tail of the mRNA.

Identification and characterization of viral structural proteins of infectious salmon anemia virus.

Infectious salmon anemia virus (ISAV) is an unclassified Orthomyxovirus that has been shown to contain a segmented genome with eight single-stranded RNA species coding for 10 viral proteins. Four major structural proteins were characterized in the present study: two glycosylated proteins with estimated molecular masses of 42 and 50 kDa, one 66-kDa phosphoprotein, and one 22-kDa protein. Examination of lysed virions revealed the two glycoproteins and the 22-kDa protein in the soluble fraction, while the 66-kDa phosphoprotein and a minor part of the 22-kDa protein were found in the pelleted fraction.

The major allergen (parvalbumin) of codfish is encoded by at least two isotypic genes: cDNA cloning, expression and antibody binding of the recombinant allergens.

The major allergen (parvalbumin) from cod, designated Allergen M Gad c 1, has been intensively studied both from the structural and immunological sides. In the present study, transcripts of two isotypic parvalbumin genes in Atlantic cod were identified and characterized. Subsequently, subfragments were inserted into the expression vector pET-19b, generating plasmids with coding capacity for complete parvalbumin polypeptides fused to an N-terminal his(10) tag.

Analysis of two IgM isotypes in Atlantic salmon and brown trout.

Atlantic salmon (Salmo salar) possesses two distinct subpopulations of polymeric IgM which are separable by anion exchange chromatography. Consistent with this finding there are two isotypic IgM heavy chain genes, CmuA and CmuB, in the genome of this species, presumably as a result of ancestral tetraploidy. In the present study it was shown that IgM of brown trout (Salmo trutta) is also separated into two subpopulations by anion exchange chromatography, while IgM of rainbow trout (Oncorhynchus mykiss) and Arctic char (Salvelinus alpinus) are eluted in one peak.

Segment 8 encodes a structural protein of infectious salmon anaemia virus (ISAV); the co-linear transcript from Segment 7 probably encodes a non-structural or minor structural protein.

In this study we present the cloning, expression and partial identification of Genomic Segment 7 of infectious salmon anaemia virus (ISAV). The nucleotide sequence corresponding to Segment 7 was isolated from a bacteriophage lambda cDNA library and contained 2 overlapping open reading frames (ORFs) of 903 and 522 bases respectively. It also contained an ISAV-specific conserved nucleotide motif in the mRNA 5' region.

Cloning and identification of the infectious salmon anaemia virus haemagglutinin.

Infectious salmon anaemia virus (ISAV) is an orthomyxo-like virus that causes serious disease in Atlantic salmon (Salmo salar). Like the orthomyxoviruses, ISAV has been shown to possess haemagglutinin (HA) activity. This study presents the cloning, expression and identification of the ISAV HA gene, which was isolated from a cDNA library by immunoscreening.