Isolation and characterization of gamma delta T lymphocyte cell lines from Sinclair swine peripheral blood.

Sinclair miniature swine represent a breed of miniature swine which display a significant incidence of inheritable melanoma which undergo a developmentally regulated spontaneous regression. In an attempt to characterize the host cellular immune response to the melanoma, lymphocyte cell lines have been generated from peripheral blood and designated as peripheral blood lymphocyte cell lines (PBLCLs). The cell lines were expanded in vitro without the addition of exogenous mediators, cloned by limiting dilution, and characterized by flow microfluorimetry, Western, and Northern blot analysis. The cell lines were shown to be CD2-, CD4-, CD8-, and slg-, a phenotype consistent with a null cell population described in swine. The null cell population in swine has been reported to consist of a subpopulation of cells which express the gamma delta T cell receptor (TCR) heterodimer, swine gamma delta T lymphocytes. The PBLCLs were further analyzed by flow microfluorimetry and observed to express the IL-2R, swine MHC Class II antigens, and the endothelial lymphocyte adhesion marker (CD44), which can function as a homing receptor for the skin. In addition, the PBLCLs were observed to express the antigen which is recognized by mAb 86D, an antibody that has been reported to recognize an external epitope on a subset of gamma delta TCR bearing swine T lymphocytes. Western blot analysis of Triton X-114 phase fractions of a PBLCL revealed a protein recognized by the W6 antibody, an antibody which recognizes a conserved region of the C delta chain. Furthermore, Southern and Northern blot analysis indicated that the PBLCL have rearranged the TCR gamma chain gene and express mRNA from the TCR gamma and delta chain genes prior to and following treatment with ionomycin or Concanavalin A. Therefore, the data indicates that the PBLCLs represent swine gamma delta T lymphocyte cell lines which should enable us to enhance our understanding of the role of gamma delta T lymphocytes in the porcine immune system.

Aeromonas, acclimation, and penicillin as complications when leeches are applied to skin flaps in rabbits.

The medicinal leech, Hirudo medicinalis, has been recognized by plastic surgeons for its ability to reduce congestion and improve blood flow in grafted skin flaps by withdrawing excess blood. The leech's ability to digest blood is due to the presence of Aeromonas hydrophila in the gut of the leech. In this report we describe the occurrence of Aeromonas hydrophila septicaemia in rabbits used in a study to evaluate the efficacy of the medicinal leech on abdominal skin flap survival. In New Zealand White rabbits, twin 5 x 10 cm abdominal skin flaps were prepared and the epigastric vein was ligated to produce a model of venous congested skin. After 12 hours, a leech was applied to one of the congested abdominal flaps and skin survivability was assessed and compared with the unleeched flap. Five rabbits died acutely approximately 24 hours post-operatively. Gross necropsy, bacteriology and histopathology findings indicated that A. hydrophila was the causative agent of the septicaemia-toxaemia syndrome with an associated pneumonia and typhlitis. Review of the management and the experimental surgery protocol suggested that the two major disposing factors of Aeromonas septicaemia in these rabbits were stress and excessive prophylactic administration of penicillin.

Association of uveal melanocyte destruction in melanoma-bearing swine with large granular lymphocyte cells.

Sinclair strain miniature swine spontaneously develop and regress malignant melanoma lesions, with uveitis and vitiligo occurring subsequent to tumor regression. Peripheral blood lymphocytes (PBL) of Sinclair swine undergoing tumor regression and melanocyte destruction demonstrated significant lytic activity against K562, porcine semiallogeneic uveal melanocytes, and melanoma cells in 4-h chromium release assays. The ability of porcine PBL to lyse these target cells appears to be an age-associated immune response, as evidenced by the relative inability of PBL of pigs less than 4 weeks old to lyse target cells. In young adult pigs, however, PBL cytotoxic activity significantly increases; piglets 6 weeks old and older demonstrate efficient killing of all three targets. Conjugate formation assays demonstrate that a lymphoid effector cell possessing large granular lymphocyte (LGL) morphology may be involved in melanocyte destruction. These findings suggest that a LGL subpopulation may participate in melanoma and melanocyte destruction which can induce a uveitic syndrome in Sinclair swine with melanoma.

Host environment as a modulating factor of swine natural killer cell activity.

The large granular lymphocyte (LGL) population includes such heterologous effector cells as the natural killer (NK), lymphokine activated killer (LAK), antibody dependent cellular cytotoxic (ADCC) and non-MHC restricted T cells. These LGL subpopulations have all been associated with NK activity. In some species, enhanced NK activity is correlated with exposure to viral, bacterial and parasitic agents. Consequently, the host environment could serve as a modulatory factor of NK activity in laboratory animals. During our investigation of tumor regression in melanoma swine, we observed marked differences in the NK activity of peripheral blood lymphocytes collected from two separate groups of Sinclair melanoma miniature swine maintained under different conditions. Group A pigs were vaccinated and extensively treated for endo- and ectoparasites while group B swine were not. In addition, chronic exposure to infectious and parasitic diseases have been documented in the group B swine. Peripheral blood NK activity was assessed by standard in vitro 4-h chromium release assays. The NK activity of group B swine was markedly exaggerated when compared to group A swine. Thus, the significance of NK activity may be distorted as a result of the modulating effect of pathogen exposure.

A comparison of body and organ weights, physiologic parameters, and pathologic changes in target organs of rats given combinations of exercise, anabolic hormone, and protein supplementation.

This study was engineered to closely mimic the training protocol of a competitive athlete using repetitive exercise sessions, dietary protein supplementation, and anabolic steroids. The length of the study was 37 days. Thirty-four Sprague Dawley male rats Crl:CD(SD)BR in the weight range of 150 to 175 grams were used. These were randomly divided into four exercise groups, varying protein consumption and anabolic hormone administration. Eight nonexercised control rats were kept separate from the study to act as a comparison for organ weight, hematology, and serology. Exercise consisted of a 30 minute swim three times a week. Parameters recorded were total body weight and percent gain, wet and dry muscle weight of the isolated anterior tibialis, weights of designated organs, hematologic profiles, and serum chemistries including triglycerides, high density and low density lipids. Histopathology of known "target organs" was performed and bone marrow aspirates were taken. Body weights of rats given anabolic steroid, protein supplement, and exercise were the lowest of all groups. Testicular weight was significantly decreased in the anabolic groups. Anabolic groups had the lowest hematocrits of the exercised groups. All serology values were within normal ranges and no pathologic changes were seen in any of the tissues taken from specific "target organs."

Terminal deoxynucleotidyl transferase activity in thymocytes of kittens.

Activity of terminal deoxynucleotidyl transferase (TdT) was measured in the thymus of 8- to 14-week-old kittens. Microscopic evidence of involution or other morphologic changes were not observed in formalin-fixed hematoxylin and eosin-stained thymic tissue sections. Thymic tissue from young kittens (8 weeks old) had low TdT activity, as determined by enzymatic catalysis or immunoassay procedures. Markedly higher TdT activity was measured in thymic tissue of older kittens (13 to 14 weeks old). Feline TdT catalyzed the polymerization of deoxynucleotides at a higher rate in Mn2+ than in Mg2+. Results of protein immunoblotting experiments indicated that the major form of feline thymic TdT is a single, high molecular weight polypeptide in 13- to 14-week-old kittens. Detection of TdT activity in the feline thymus indicated that TdT may have the same diagnostic and therapeutic value in feline oncology as in human oncology.