Seal Cells Research Articles

Suppression of natural killer cell activity in harbour seals ( Phoca vitulina) fed Baltic Sea herring

Mass mortalities among marine mammal populations in recent years have raised questions about a possible contributory role of contaminants accumulated through the marine food chain. While viruses were shown to be the primary cause of the outbreaks, an immunotoxic action by organochlorine chemicals in affected animals could not be ruled out. We carried out a 2 1 2 - year immunotoxicological experiment in which two groups of 11 harbour seals each were fed herring from either the relatively contaminated Baltic Sea or the relatively uncontaminated Atlantic Ocean. Seals in the Baltic Sea group accumulated 3–4 times higher levels of Ah-receptor-mediated 2,3,7,8-TCDD Toxic Equivalents in blubber than did their Atlantic counterparts following 2 years on the respective diets. Blood was sampled a total of 17 times during the course of the experiment for immunological evaluation, during which time the natural cytotoxic activity of peripheral blood mononuclear cells isolated from seals fed Baltic Sea herring declined to a level approximately 25% lower than that observed in seals fed Atlantic herring ( P < 0.01). Natural killer (NK) cell activity has not been previously described for a marine mammal species. We characterized the natural cytotoxic activity of harbour seal peripheral blood mononuclear cells (PBMC), and found this to be interleukin-2 (IL-2) responsive, sensitive to antibody anti-asialo GM1, and it was higher against a virus-infected target cell, like NK cells described for other mammals. As NK cells are leukocytes which play an important role in the first line of defence against viruses, the observed impairment of NK cell activity in the seals feeding on the Baltic Sea herring suggests that exposure to contaminants may have an adverse effect on the defence against virus infections in seals inhabiting polluted waters in Europe. This may therefore have affected the severity of the infections, the survival rates and the spread of infections during recent epizootics.

Ultrastructural study of unidentified inclusions in the cornea and iridocorneal angle of dogs with pannus

SUMMARY The corneas and/or the iridocorneal angles of 13 dogs were examined morphologically by use of transmission electron microscopy. Virologic identification techniques also were used for tissue from 2 dogs. Four dogs had clinical signs of chronic superficial keratitis or pannus, 9 dogs had normal eyes. In the tissue from 7 dogs (4 German Shepherd Dogs with chronic superficial keratitis; 2 German Shepherd Dogs and 1 mixed-breed dog with normal eyes) we found unusual cytoplasmic inclusions. Inclusions were not found in dogs of other breeds with normal eyes. The inclusions were observed in comeal fibroblasts, vascular endothelial cells, and macrophages, as well as in trabecular cells and fibroblasts of the iridocorneal angle. They were often grouped within the rough endoplasmic reticulum or found free in the cytoplasm. The cylindrical particles had a helical substructure, measuring 20 nm in diameter and up to 400 nm long, with a distance of 10 nm for the repeating turns. Results of virologic culturing on canine and seal kidney cells were negative, as was staining with fluorescein isothiocyanate-labeled antibodies against canine distemper virus, canine herpesvirus, canine parvovirus, and canine adenovirus. Relevance of the inclusion bodies described is discussed. Because our results seem to hint at a correlation between presence of the rod shaped particles and German Shepherd Dogs with pannus, we suggest that an etiologic or pathogenic connection exists that merits further examination.

Morbillivirus infection of seals (Phoca vitulina) during the 1988 epidemic in the Bay of Heligoland. I. Mode, frequency and significance of cultural virus isolation and neutralizing antibody detection.

From 16 (14%) out of 112 dead or euthanized seals originating from wildlife and seal orphanages phocine morbillivirus was isolated. The majority of viral isolates in cell cultures was obtained from lung homogenates of 15 out of 71 free-ranging seals (21%). The virus was isolated by longterm cultivation in roller cultures of seal kidney cells. The phocine morbillivirus was detected by typical cytopathogenic alteration and by peroxidase-linked antibody (PLA) assay, respectively. A neutralization test based on PLA was used for antibody detection in seals using a canine distemper virus (CDV) strain and in parallel one of the phocine morbillivirus isolates. All sera tested were proven to contain neutralizing antibodies of higher titres against the latter virus than against the CDV strain. Several seals furnished morbillivirus isolates and at the same time exhibited neutralizing antibodies of low to medium titres. No viral isolates were obtained from the majority of sick animals with moderate to high neutralizing titres (greater than 1/1,000). The significance of these findings is discussed in relation to the cause of the mass mortality amongst seals observed in 1988 in the Bay of Heligoland.

The isolation and partial characterization of a highly pathogenic herpesvirus from the harbor seal (Phoca vitulina).

This report describes the first isolation and partial characterization of a herpesvirus from the harbor seal (Phoca vitulina). The virus was isolated during a disease outbreak in a group of young seals nursed in a seal orphanage in The Netherlands. Almost half of the seals died with symptoms of acute pneumonia and focal hepatitis and the virus was isolated of organs of most of the dead animals. Seven out of ten seals of which paired serum samples were obtained showed seroconversion in a virus neutralization test during this outbreak. The virus was tentatively characterized as a herpesvirus (seal herpesvirus: SeHV or phocid herpesvirus 1) on the basis of its characteristic morphology in electron microscopy, buoyant density in sucrose, sensitivity to ether and heat treatment and its antigenic relationship with other probable members of the Alphaherpesvirinae subfamily. The virus caused cytopathic changes within 24 hours after inoculation in seal kidney cells, consisting of a focal rounding of cells and syncytium formation. No cytopathic changes were observed in the cells of nine other mammalian species tested.

Growth potential of sheep and sea mammal cells transformed by SV40 early region DNA.

AbstractNormal fibroblasts of bearded seal, northern fur seal, sea lion, domestic sheep, and normal kidney cells of spotted dolphin and Pacific common dolphin have been transformed by fragments of SV40 DNA containing the entire early region. The transformed, T-antigen-positive cell strains grew to higher saturation densities and, except for the transformed dolphin kidney cell strains, were able, albeit poorly, to form colonies in soft agar medium. The transformed northern fur seal, spotted dolphin and Pacific common dolphin cell strains have remained diploid, the transformed sheep cells have become hypodiploid due to Robertsonian translocations, and the transformed bearded seal and sea lion cells had become hypotetraploid. Although all the transformed cells have acquired increased divisional potential and prolonged lifespan in cell culture, only the hypotetraploid cell strains of bearded seal and sea lion have evolved into continuous cell strains.

Electronic Absorption Spectrum of 2,4-Dibromoaniline in Vapor

The near ultraviolet absorption spectrum of 2,4-dibromoaniline in vapor phase has been photographed for the first time on a Q-24 Zeiss Medium Quartz Spectrograph. The quartz to Pyrex graded seal cells were used. The conventional hydrogen lamp was the source of continuous radiation. The tube lengths were varied from 50 to 125 cm and the temperatures from 30° to 80°C. The sharp bands appear with a cell of length 100 cm at the temperature 43°C. The spectra were photographed on Kodak B10 plates.