Bovine fibroblast interferon (BoF-IFN), produced in bovine embryonic kidney cell cultures by priming and infection with bluetongue virus, was partially purified by controlled pore glass chromatography. The partially purified B0F-IFN then was subjected to beaded agarose affinity chromatography. The IFN eluted by affinity chromatography in 2 distinct fractions-1 after the addition of 1M NaCl and the other one after the addition of 1.5M NaCl containing 50% ethylene glycol. Analysis of fractions by sodium dodecyl sulfate/polyacrylamide-gel electrophoresis revealed a broad molecular weight range (14,900 to 27,900) for the IFN eluted by 1M NaCl, and 2 discrete molecular weight ranges (16,000 to 19,500 and 28,300 to 34,000) for IFN eluted by 1.5M NaCl containing 50% ethylene glycol. The specific activity of the IFN eluted with 1.5M NaCl containing ethylene glycol was 2.85 X 10(6) U/mg of protein, compared with 5.7 X 10(5) U/mg of protein in the controlled pore glass-purified IFN.

Hybridomas were selected for secretion of monoclonal antibodies directed against pseudorabies virus (PRV) glycoproteins. Each monoclonal antibody was capable of neutralizing PRV in vitro in the presence of complement. This panel of antibodies was used in passive immunization studies to protect mice and swine from PRV-induced mortality. The most protective antibody in mice was 3A4, specific for PRV glycoprotein gp50, which afforded as high as 100% protection. Although antibody 3A4 was partially protective in swine, antibody 3D11, which is specific for PRV glycoprotein gIII, afforded greater protection-83% protection when ascitic fluid was used and 100% protection when immunoglobulin concentrated from cell cultures was used at a dose of 150 mg/pig. These studies demonstrated that monoclonal antibodies may be useful for short-term prophylaxis against PRV-induced disease and that antibody directed against either PRV gylcoprotein gIII or gp50 is sufficient to protect animals from PRV-induced mortality.

Bovine fibroblast interferon (BoF-IFN), produced in primary bovine embryonic kidney cell cultures after priming and infection with bluetongue virus, was purified by controlled pore glass (CPG) chromatography to a specific activity of 10(6) U/mg of protein, with 40% recovery of the original activity. The crude IFN was concentrated more than sevenfold during purification. This proved to be a relatively simple, practical method of obtaining sufficient quantities of partially purified natural BoF-IFN for further studies. The CPG-purified BoF-IFN was further concentrated by sequential ultrafiltration and was analyzed by sodium dodecyl sulfate/polyacrylamide-gel electrophoresis (SDS-PAGE). Interferon, recovered from denaturing conditions either by dialysis against phosphate-buffered saline solution or by dilution in cell culture medium containing 10% fetal bovine serum, migrated as a single stainable protein with molecular weight of 21,000 on analytic SDS-PAGE gels. Recovered IFN activity from preparative SDS-PAGE totalled 8.7% of that applied. Attempts to further pruify CPG-purified BoF-IFN by zinc chelate affinity chromatography were unsuccessful.

Relative pathogenicity of 151 Escherichia coli isolates from 36 calves with bacteremia after necropsy was studied by measurement of the LD50 after mice were inoculated IP with E coli isolates. Study of virulence factors and markers revealed that the pathogenicity of E coli was associated with the production of hydroxamate siderophores and with resistance to serum bactericidal effects. Production of colicins, including colicin V, and of surface antigen 31A was correlated with virulence. The close association between phenotypic expression of virulence factors and markers was consistent with a hypothesis of a localization of genes coding for virulence factors and markers on the same plasmid.

Three experiments were conducted to investigate experimentally the occurrence of periparturient nematode egg rise in ewes and the hormonal modulation of Haemonchus contortus infections. In the first experiment, fall-bred and winter-bred pregnant (n = 4 and 14, respectively) and nonpregnant (n = 5 and 29, respectively) ewes were treated with anthelmintic and were pastured together on fields that were contaminated with H contortus. Three weeks before lambing, all ewes were placed in concrete pens; fecal egg counts for the winter-bred group were obtained on alternate days. Pregnant and lactating ewes had significantly larger numbers (P < 0.01) of H contortus eggs than did the nonpregnant controls 1 week before and after lambing. Lactating, fall-bred ewes had significantly (P < 0.01) more adult worms in their abomasum through natural acquisition than the nonpregnant controls. In the second experiment, fall-bred and winter-bred helminth-free, pregnant (n = 4 and 8, respectively) and nonpregnant (n = 3 and 15, respectively) ewes were inoculated on 5 alternate days, beginning 70 days after breeding with 20,000 infective H contortus larvae. The ewes were maintained on concrete pens throughout pregnancy. Fecal egg counts were significantly (P < 0.05) greater in pregnant ewes, beginning 1 week before lambing until 1 week after lambing. Abomasums of lactating ewes from both lambing seasons yielded significantly (P < 0.01) more adult worms at necropsy than nonpregnant ewes. In the third experiment, ewes were ovariectomized (n = 15) or sham-operated (n = 9); half of the control ewes were bred. Beginning on day 70 of pregnancy, all ewes were inoculated orally with 20,000 infective H contortus larvae on 5 alternative days. Abomasums were removed from all ewes after lambing, and adult worms were recovered. Pregnant ewes and half of the ovariectomized ewes had significantly (P < 0.05) more worms than did the sham-operated ewes.

Twelve Holstein calves mere used to determine the prophylactic efficacy of ivermectin against challenge exposure with gastrointestinal and pulmonary nematodes. Two groups of 6 calves (mean body weight, 205 kg) each were formed by restricted randomization according to body weight. Group-l calves served as nonmedicated controls. Each calf of group 2 was orally given one prototype sustained-release bolus designed to deliver ivermectin at a continuous daily dose of 8 mg. Third-stage nematode infective larvae were given to the calves on posttreatment days 28 and 42. The calves were euthanatized 77 or 78 days after treatment. Ivermectin was 100% effective (P < 0.05) in preventing the establishment of infection by Haemonchus placei, Ostertagia ostertagi, Cooperia spp (C punctata, C oncophora, C surnabada), Nematodirus helvetianus, Oesophagostomum radiatum, and Dictyocaulus viviparus and was > 99% effective against Trichostrongylus axei. Incidental infection by Trichuris spp was reduced by 94% (P = 0.08).

A commerical radioimmunoassay kit designed for measuring gastrin in human serum was validated for use with equine serum. This nonextraction, double-antibody procedure uses an antiserum with broad specificity for molecular forms of gastrin. Synthetic human gastrin (G17-I) was added to pooled equine serum, and the observed assay values were compared with the mass added. Recovery was 99 to 115% in the gastrin concentration range of 40 to 640 pg/ml. Dilutions of postprandial serum with serum from fasted horses were assayed, and the inhibition curves were compared with those of the human gastrin kit standards, using a log-logit transformation. The slopes of the sample dilution plots were not significantly different from the slopes ofthe standard curves. Ethylenediamine tetraacetate and heparin adversely affected the assay, resulting in lower assayed gastrin concentration values. The intra-assay coefficient of variation (n = 10) was 3.8%, and the interassay coefficient of variation (n = 6) was 11.2%. The assay sensitivity, as reported by the manufacturer, is 8 pg/ml. Gastrin concentrations in serum from fasted horses ranged from undetectable values (less than 8 pg/ml) to 17.5 pg/ml, and peaked at a mean value (n = 6) of 70 pg/ml 3 hours after feeding. Serum cortisol values monitored during the postprandial blood collection period were in the normal range for horses.

Using isolated autoperfused intestinal segments, the effects of flunixin meglumine administration on systemic arterial blood pressure, jejunal blood flow, vascular resistance, motility, arteriovenous oxygen difference, and oxygen consumption were determined in 10 anesthetized ponies ventilated with a mixture of halothane and oxygen. Saline solution or flunixin meglumine (1.1 mg/kg of body weight) was infused as a single bolus into the left jugular vein. By 10 minutes, flunixin meglumine increased systemic aterial blood pressure and increased intestinal vascular resistance. The jejunal blood flow, however, was not significantly decreased until 1 hour after flunixin meglumine administration. Intestinal motility, arteriovenous oxygen difference, and oxygen consumption were unchanged. Results indicated that acute administration of flunixin meglumine increases systemic arterial pressure and intestinal vascular resistance, but the resulting intestinal vasoconstriction does not lead to compromise of intestinal viability.

Effects of age and season on type and occurrence of sperm abnormalities were examined in semen samples collected from 3 groups of Nubian bucks at ages of 4 to 9 months, 10 to 21 months, and 39 to 50 months. The average total percentage of sperm abnormalities at the onset of puberty (141 +/- 4 days) was 64.6 +/- 14.8% (head, 19.5 +/- 13.6%; middle piece, 17.2 +/- 9.3%; and proximal protoplasmic droplets, 14.6 +/- 10.5%), but this improved rapidly and was reduced to 12.5 +/- 7.5% by 8 months of age (head, 1.9 +/- 4.5%; middle piece, 4.6 +/- 2.8%). Further increase in age, at least up to 4 years, did not reveal a significant effect (P less than 0.05) on the type of percentage of total abnormalities. Similar to age, a comparison of data among seasons did not reveal a significant effect on the type or occurrence of sperm abnormalities in 10- to 21-month-old or 39- to 50-month-old bucks. Seemingly, Nubian bucks started producing good quality semen at 8 months of age, and season did not influence sperm abnormalities.

Cells acquired from lymph node biospy specimens obtained from 58 dogs scheduled to undergo chemotherapy for lymphoma were immunophenotyped, using a microlymphocytotoxicity (MLCT) assay comprising a panel of well-characterized monoclonal antibodies (MAB) specific for canine cell surface antigens. Cells from 54 of the dogs concurrently were tested cytofluorometrically, using surface immunoglobulin (SIg) as a marker for B cells and the MAB DT2 specific for peripheral blood T cells. The MLCT results indicated frequent coexpression of antigens identified by DT2 antibody and, to a lesser extent, by 1A1 antibody on SIg-positive cells, suggesting that these antigens may be associated with other types of less-differentiated lymphoid cells, in addition to being associated with mature T cells. Class-II major histocompatibility antigens, as recognized by MAB H81.98.71, HB10a, and H40.315.7, were detected on most SIg-positive cells, but generally were lacking on SIg-negative, DT2-negative cells. The MAB Wig4, reactive with canine monocytes, recognized relatively few cells (11 of 58). Response to chemotherapy was not correlated with reactivity to MAB DLy6 specific for resting lymphocytes or to MAB W3G10 specific for a polymorphic antigen associated with the canine major histocompatibility complex. The MLCT assay appears to be efficient, rapid, and inexpensive for immunophenotyping cells from lymphoma biopsy specimens.