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Two lymphoblastoid cell lines were isolated from different pigs and were maintained in culture for over 100 passages or 20 months. These cell lines were characterized by their cell surface antigens, ability to stimulate a mixed lymphocyte reaction and production of immunoglobulin. When tested against a panel of monoclonal anti-cell surface antigen antibodies, only those monoclonal antibodies which detect porcine class I or II molecules reacted against the lymphoblastoid cell lines in a microcytotoxicity assay. The two pig cell lines could stimulate peripheral blood mononuclear cells in a mixed lymphocyte reaction. P-SC(1) and P-16(2) also demonstrated a dependency upon the presence of 2-mercaptoethanol for cell division. The secretion of pig immunoglobulin by P-SC(1) or P-16(2) was first demonstrated by ELISA using a polyclonal anti-swine IgG (heavy and light chain) serum. By the use of monoclonal anti-IgA, IgG or IgM antibodies in an enzyme-linked assay on Western blots of P-SC(1) or P-16(2) lysate/supernatant, the two cell lines were demonstrated to be producing a whole monomeric IgA molecule and a mu chain.

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Intestinal phospholipase B activity in pigs inoculated with transmissible gastroenteritis (TGE) virus was studied. Phospholipase activity was quantified by measuring the hydrolytic release of free fatty acids in homogenized intestinal tissue incubated with lysophosphatidylcholine. An increase in enzyme activity was observed in the cranial and caudal portions of the ileum and jejunum in pigs killed 3, 6, and 8 days after inoculation with TGE virus. Seemingly, phospholipase B may be part of the host immune response against TGE viral infection.

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Mucus-producing cells were isolated from swine trachea mucosa by a method that included enzymatic digestion of the epithelial surface with Dispase, a neutral protease from Bacillus polymyxa, and differential attachment of the washed cells to culture flasks coated with collagen. Epithelial cells were the major cell type isolated by these procedures. Ciliated cells that did not attach to the flasks were removed by decantation , and fibroblasts were destroyed by the bacterial protease. The isolated cells synthesized respiratory mucins and the rate of secretion was increased about threefold when tracheas were exposed to sulfur dioxide. The cultured cells incorporated both [35S]O4 and [I-14C]N-acetylglucosamine into secreted mucin glycoproteins. The secretion of glycoprotein increased for about 3 d until the cells became confluent, and then a constant rate was observed for a period of at least 7 d. This increase in the output of mucin glycoprotein during the initial 3 d of culture was accompanied by a corresponding increase in the number of mucus-producing cells in the flasks. The results obtained in these and subsequent studies suggest that the rate of formation of mucus-producing cells may be a rate limiting step in the regulation of mucin glycoprotein synthesis in tracheal epithelium. The chemical, physical, and immunological properties of the glycoprotein secreted by isolated tracheal epithelial cells were very similar to the mucin glycoprotein purified from washes of swine trachea epithelium. The purified mucin glycoproteins showed complete cross-reaction with antibodies to trachea mucin glycoprotein. They were eluted near the void volume during gel filtration of Sepharose CL-6B columns. The glycoprotein isolated from culture media under the standard assay conditions had nearly the same carbohydrate composition as samples purified from washes of trachea epithelium. Reduced oligosaccharides released by beta-elimination with dilute alkaline borohydride showed similar elution profiles during chromatography on Bio Gel P-6 columns. Taken collectively, these results suggest that the isolated epithelial cells secreted mucin glycoproteins that were very similar to those synthesized by the intact trachea epithelium under standard incubation conditions.

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Pigs 8 to 10 weeks of age were orally infected with transmissible gastroenteritis (TGE) virus or infected by inoculation of the virus into Thirty-Vella loops of jejunum. Concentrations of immunoglobulin (Ig) A, IgM, and IgG in serum, saliva, jejunal secretions, loop secretions, and bile were determined by solid-phase radioimmunoassay for TGE virus-infected and control pigs. A multiple-staining fluorescent antibody technique was used to determine the relative numbers of IgA-, IgM-, and IgG-producing plasma cells in intestinal mucosa, mesenteric lymph node, spleen, iliac lymph node, and submandibular salivary gland. The numbers of IgA- and IgM-producing plasma cells were greater in the jejunal mucosa of pigs infected and reinfected orally with TGE virus than in that of the control pigs. There was also an increase of IgA- and probably of IgM-cells in the submandibular salivary glands. Similar numerical increases of IgA- and IgM-cells were observed in jejunal mucosa and salivary glands of all pigs with intestinal loops whether exposed to TGE virus or not. Increases in plasma cells in mucosa or salivary gland were not associated with increases in concentrations of IgA or IgM in the respective secretions or serum. The data support the hypothesis that after stimulation, IgA- and IgM-producing cells leave the intestinal mucosa and are trapped by distant secretory epithelial. The absence of a simultaneous increased concentration of IgA and IgM in saliva and intestinal secretions indicates that in an intact epithelium, the transport of IgA and IgM mediated by secretory component is probably saturable.

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Polymyositis was diagnosed in nine dogs. Factors utilized in making the diagnosis included (1) muscle pain or weakness, (2) high concentrations of serum muscle enzymes, (3) electromyographic abnormalities, and (4) histopathologic evidence of muscle necrosis and inflammation. Clinical signs included muscle pain, weakness, stilted gait, and pyrexia. Serum muscle enzyme concentrations were high in only three dogs. There was no apparent correlation between enzyme concentrations and severity of clinical involvement or degree of muscle necrosis on biopsy. Electromyographic changes included polyphasic motor unit potentials, fibrillation potentials, and positive waves. Variable degrees of muscle regeneration, degeneration, and inflammation were seen. Prednisone (2.2 mg/kg, OD, per os) was used effectively to treat four dogs. One dog improved initially but was euthanatized later when clinical signs became more pronounced. Three other dogs developed aspiration pneumonia secondary to megaesophagus and either died or were euthanatized.

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The immune defense system of the kidney was studied by inducing ascending pyelonephritis in rats with Corynebacterium renale. With the fluorescent antibody technique, C renale organisms were observed in the renal pelvis, but were not coated with antibody until they reached the medulla. Histopathologic evaluation of renal tissues collected serially after inoculation confirmed the presence of infection in the medulla when antibody coating occurred. Serum anti-C renale antibody concentrations increased after antibody-coated bacteria appeared in the urine and kidney. Free anti-C renale antibody was not detected in urine from infected rats, using the microagglutination assay. Antibody coating appears to occur only after C renale organisms invade the medulla during ascending pyelonephritis.

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Trichinella spiralis was studied in outbred swine to determine whether infection would cause an increase in intestinal phospholipase B (EC 3.1.1.5) activity and in number of peripheral eosinophils. Intestinal phospholipase B activities increased and were accompanied by eosinophilia. The response was similar to that found in rodents infected with helminth parasites, thus demonstrating that phospholipase B is not unique to rodent models and is probably part of the complex immune response of the host in defense against parasitic infections.

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A diagnosis of vertebral multiple myeloma, based on radiographic evidence of osteolytic lesions and the finding of monoclonal paraprotein and large numbers of plasma cells in bone marrow biopsies, was made in a mature Doberman Pinscher. The abnormal serum paraprotein was a cryoglobulin of the immunoglobulin A class. Neurologic signs associated with the tumor included pain, progressive pelvic limb paresis, and paraplegia that developed during a 6-week period.

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The technique described is a modification of a qualitative hemolytic radial diffusion technique. The test involves the use of sensitized sheep erythrocytes that have been incorporated into agarose. Tube dilutions were made of chicken serum and samples of each dilution were placed into wells cut in the agarose. The test is quantitative for hemolytic complement in that the highest dilution showing visible hemolysis of sensitized erythrocytes in agarose is determined to be the endpoint for that serum sample. The test as compared with the standard tube assay was determined to be less sensitive by approximately one dilution. The advantages of speed, simplicity, and cost more than offset the decrease in sensitivity of the test.

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