[Potency testing of veterinary vaccines, rabies vaccines as an example]

Vaccines which are produced commercially should be controlled with respect to their efficacy (potency) and their "harmlessness" to the recipient animal. The basis for any potency test is the protection test in the target animal species. When a vaccine has been shown to be capable of protecting a particular species from a certain disease, alternative methods for potency testing often can be developed. The justification of the latter is that experiments which analyze the protection are cost-intensive, require a large number of animals and give only a moderate degree of reproducibility. Methods such as protection experiments in laboratory animals, the induction of the substances responsible for protection (such as antibodies) in target or laboratory animals as well as with in vitro tissue culture systems, or the quantitative determination of the immunogens (the components of a vaccine which should be responsible for protection) may be used only if their results correlate with those obtained from protection experiments in the target animal species. Rabies glycoprotein has been implicated as the main agent responsible for the induction of protection against rabies. The higher the content of glycoprotein in a rabies vaccine, the greater will be the potential of the vaccine to induce protection against the disease. Analyses of the rabies glycoprotein content in vaccines can make use of a number of methods which have proven acceptable (the immunodiffusion test, the antibody binding assay and the ELISA). However, in veterinary medicine most vaccines are associated with an adjuvant - a substance which should amplify the immune response of an animal against a vaccine. Since the adjuvants and vaccines in such preparations are inseparable, the presence of an adjuvant in a vaccine reduces the applicability of many in vitro methods. Thus, the above mentioned methods and possibilities for their adaptation to the analysis of adjuvanted vaccines will be discussed.

Predicting death from ruptured abdominal aortic aneurysms

BACKGROUND

We have previously reported preoperative and immediate postoperative formulae to estimate mortality in patients with ruptured abdominal aortic aneurysms (rAAA). In this study, we prospectively compared these formulae in patients with rAAA with their actual outcomes.

METHODS

Information was collected on 134 patients from two centers over a 3-year period. Preoperative mortality risk was estimated using coefficients for age, level of consciousness, and cardiac arrest. Mortality risk in the immediate postoperative state was based on the presence of coagulopathy, ischemic colitis, prolonged requirement for inotropes, time from arrival at hospital to surgery, patient age, perioperative myocardial infarction, renal failure, and pre-operative hemoglobin level.

RESULTS

The average age was 73 years (range 30 to 92 y) and 20 of 134 (15%) patients were women. Sixty-three patients (47%) survived. For patients with a calculated preoperative mortality risk of >90%, the sensitivity, specificity, and positive and negative predictive values were 25%, 98%, 95%, and 54%, respectively. For a mortality risk >80%, these values were 37%, 94%, 87%, and 57%, respectively. For patients with an estimated immediate postoperative mortality risk > or = 90%, the sensitivity, specificity, and positive and negative predictive values were 17%, 87%, 60%, and 49%, respectively. For a predicted mortality > or = 80%, these values were 22%, 84%, 60%, and 50%, respectively.

CONCLUSIONS

Our formula for predicting mortality for preoperative rAAA patients may be useful for patients with an estimated mortality risk >/=90%, based on the high positive predictive value. The formula for immediate postoperative rAAA patients was not useful in predicting death.

Interspecies major histocompatibility complex-restricted Th cell epitope on foot-and-mouth disease virus capsid protein VP4

T-cell epitopes within viral polypeptide VP4 of the capsid protein of foot-and-mouth disease virus were analyzed using 15-mer peptides and peripheral blood mononuclear cells (PBMC) from vaccinated outbred pigs. An immunodominant region between VP4 residues 16 and 35 was identified, with peptide residues 20 to 34 (VP4-0) and 21 to 35 (VP4-5) particularly immunostimulatory for PBMC from all of the vaccinated pigs. CD25 upregulation on peptide-stimulated CD4(+) CD8(+) cells-dominated by Th memory cells in the pig-and inhibition using anti-major histocompatibility complex class II monoclonal antibodies indicated recognition by Th lymphocytes. VP4-0 immunogenicity was retained in a tandem peptide with the VP1 residue 137 to 156 sequential B-cell epitope. This B-cell site also retained immunogenicity, but evidence is presented that specific antibody induction in vitro required both this and the T-cell site. Heterotypic recognition of the residue 20 to 35 region was also noted. Consequently, the VP4 residue 20 to 35 region is a promiscuous, immunodominant and heterotypic T-cell antigenic site for pigs that is capable of providing help for a B-cell epitope when in tandem, thus extending the possible immunogenic repertoire of peptide vaccines.

Delta opioid binding selectivity of 3-ether analogs of naltrindole

Masking of the 3-phenol of naltrindole as a range of ethers caused a decrease in binding affinity at all three opiate receptors (mu, kappa, delta), however for the methyl ether, the reduction in affinity at both mu and kappa was greater than at delta, thereby increasing delta binding selectivity.

Synthesis and biological activity of 3-substituted 3-desoxynaltrindole derivatives

The 3-unsubstituted and substituted analogs of naltrindole (NTI) were synthesized using palladium-catalyzed transformations, and their binding affinity to opioid receptors was determined. Although the 3-desoxy analog showed comparable delta selectivity with that of NTI, all of the novel compounds possessed low affinity for delta receptors indicating the important role of the 3-oxygen atom of NTI for interaction with delta-opioid receptors.

Porcine myelomonocytic markers: summary of the Second International Swine CD Workshop

Forty five mAbs submitted to the Second International Swine CD workshop were analyzed by six different laboratories for their possible reactivity with porcine myelomonocytic cells using flow cytometry and immunohistochemistry. As a result of these analyses, a new swine workshop cluster, SWC9, composed of two mAbs that recognize an antigen selectively expressed on mature macrophages, was defined. In addition, several mAbs were identified, allowing the differentiation of granulocytes from monocytes/macrophages, or monocytes from macrophages. Further work is required to identify the antigen recognized by these mAbs. Nevertheless, they should already prove useful for the identification of different stages in the macrophage maturation/differentiation, and will certainly aid analyses on the complexity of the mononuclear phagocyte system in the pig. Finally, the cross-reactivity of three anti-human CD14 mAbs with porcine myelomonocytic cells was established in this workshop.

Summary of the first round analyses of the Second International Swine CD Workshop

The reactivity of 176 monoclonal antibodies (mAb) submitted to the Second International Swine CD Workshop, together with 19 internal standards, was analyzed by flow cytometry on 16 different cell types as a means of establishing the proper cell subset for later detailed clustering analyses. The exact CD subset reactivity of the 19 internal standard mAb had been characterized in the First International Swine CD Workshop. The flow cytometric analyses resulted in 40 data sets which were then subjected to statistical clustering using the Leukocyte Typing Database IV (LTDB4) software. As result of this work, 22 clusters were defined. After review of these results, panels of mAb from the defined first round clusters were assigned to cell subsets. The respective mAb in those first round clusters were then distributed to subset group researchers for further examination during the second round of the workshop.

Workshop studies with monoclonal antibodies identifying a novel porcine differentiation antigen, SWC9

Two monoclonal antibodies (mAb) within cluster M4 of the myeloid section of the Second International Swine CD Workshop, C4 (No. 144) and PM18-7 (No. 192), showed reactivity with thymocytes and among cells of myelomonocytic origin with mature macrophages but not with monocytes and granulocytes. Both mAb recognize a protein showing two bands of 205 kDa and 130 kDa under both reducing and non-reducing conditions. Although epitope mapping with these mAb could not be performed, this cluster received the SWC9 designation.

The efficacy of intra-articular morphine for postoperative knee arthroscopy analgesia

This article describes two prospective, randomized, double-blind clinical trials designed to investigate this. Trial 1 compared a conventional local anaesthetic agent (100 mg bupivacaine) injected intra-articularly (i.a.) with a control (normal saline) and 1 mg of i.a. morphine. No significant difference was noted in the first 4 hours between the groups with respect to visual analogue pain (VAS) scores. However, at 6 and 24 hours, the group of patients who received 1 mg i.a. morphine recorded lower pain scores and required less supplementary analgesia. Trial 2 assessed the dose response relationship for i.a. morphine comparing 5 mg intravenous (i.v.) morphine (control) with 1 mg and 5 mg i.a. morphine. At early time points (1, 2, and 4 hours) similar VAS pain scores were recorded for both 5 mg i.v. morphine and 5 mg i.a. morphine, both significantly lower than the group receiving 1 mg i.a. morphine. At 6 and 24 hours, 5 mg of i.a. morphine produced significantly lower pain scores, less analgesic requirement, and less sleep disturbance on the first postoperative night than the other groups. It can be concluded from these two studies that 5 mg i.a. was the most effective analgesic following knee arthroscopy.

Peptide binding to MHC class I is determined by individual pockets in the binding groove

H-2Kb and HLA-A2 are MHC4 class I molecules with a similar overall structure. Important differences between these two class I molecules reside in the structure of the individual pockets in the antigenic-peptide-binding groove. H-2Kb, which has a deep C pocket, binds specifically peptides with a tyrosine or a phenylalanine at position 5. In contrast, HLA-A2 has a shallow C pocket, which cannot accommodate large side chains at position 5. Site-directed mutagenesis was used to generate a chimera between the murine H-2Kb and the human HLA-A2 [H-2Kb/HLA-A2(C')]. The structure of this chimera is similar to H-2Kb except for the region around the deep C pocket, where residues at positions 9, 97 and 99 were substituted with those bulkier residues from HLA-A2. Peptide binding between this chimera and H-2Kb-binding peptides [VSV (52-59), OVA (257-264), and MCMV pp89 (168-176)], revealed that the deep C pocket of H-2Kb was crucial for high-affinity binding. While a peptide, VSV (52-59), was found to bind with severalfold lower 'affinity' to H-2Kb/HLA-A2(C') than to the wild-type H-2Kb, a VSV analogue with the tyrosine in position 5 (Tyr5) substituted with an alanine was found to bind with a similar 'affinity' to both MHC class I molecules. Computer-aided modelling of the H-2Kb/HLA-A2(C') complex indicates that the VSV (52-59) peptide probably binds to the chimeric MHC molecule with the peptide side chain of anchor residue Tyr5 pointing away from the groove. These results confirm a role of the individual pockets in determining peptide-binding affinity and specificity and suggest that this may be accomplished by changes in side-chain orientation.

Injuries to the ulnar carpometacarpal region: are they being underdiagnosed?

Thirteen cases with radiographic evidence of injury to the ulnar side of the hand are reviewed. These injuries included intraarticular fractures and/or dislocations of the fourth and fifth carpometacarpal joints and associated bones collectively discussed here as the ulnar carpometacarpal region. In nine the extent of the injury was not appreciated on first presentation. Injuries to this region are often difficult to assess clinically and radiographically even in experienced hands. In our experience computerized tomography (CT) scans in the longitudinal and longitudinal oblique axis best display the ulnar carpometacarpal joint surfaces and their relationship to each other. We recommend CT of the ulnar carpometacarpal region where clinical evidence of an injury to this region is not in keeping with the plain radiographic findings, and when planning surgery on a complex injury in this region.

The antibody MY4 recognizes CD14 on porcine monocytes and macrophages

Several monoclonal antibodies directed against the human CD14 antigen have been established. We now report that the antibody My4, but not LeuM3, reacts with porcine monocytes. Among porcine peripheral blood mononuclear cells (PBMC), 14.6% of the cells stain with the CD14 antibody My4, which is similar to the percentage obtained with the antiporcine monocyte antibody 74-22-15. Two-colour immunofluorescence reveals that My4 and 74-22-15 antigens are coexpressed on the same cells, and cell sorter-purified My4+ cells exhibit the morphology of monocytes. Whole blood analysis (which also shows staining of granulocytes) reveals that the average percentage of My4+ monocytes amongst all leucocytes is 5.8% with 580 cells/microliters. Furthermore, porcine peritoneal macrophages (PM) and alveolar macrophages (AM), both stain for My4, with a four-fold lower level on AM. Treatment of cells with phosphatidylinositol-specific phospholipase C decreases My4 staining, but does not affect staining with antibody 74-22-15. Immunoprecipitation with the My4 antibody from surface labelled pig mononuclear cells demonstrates a 54 kDa band similar to human CD14, and Western blotting with pig serum demonstrates two bands similar to the alpha and beta forms of human soluble CD14. Finally, the My4 antibody is capable of blocking lipopolysaccharide- (LPS)-induced interleukin-6 production in isolated PBMC. These data show that the My4 antibody recognizes genuine CD14 on porcine monocytes and macrophages.

The enhancement of lymphocyte localization in skin sites of sheep by tumor necrosis factor alpha

Using radiolabelled lymphocytes, we have demonstrated that recombinant bovine TNF alpha is potent in its ability to recruit lymphocytes from the blood into TNF alpha injected skin sites. Furthermore, TNF alpha mediates this observed increase in lymphocyte accumulation in a clear dose-response manner, and may play an important role in the mediation of DTH reactions in the skin.

Recombinant bovine interferon-gamma enhances expression of class I and class II bovine lymphocyte antigens

Recombinant bovine interferon-gamma augments expression of class I and class II histocompatibility antigens on the surface membrane of bovine lymphocytes. Immunofluorescence techniques using a series of monoclonal anti-HLA antibodies demonstrate that this enhancement is detectable as early as 24 h after incubation with rBoIFN, while maximum surface expression is obtained within 3-5 days. A concentration as low as 10 units of rBoIFN is effective. Such results may be useful for characterizing the BoLA gene products.

Effects of acute and chronic acyclovir on canine renal function

Acyclovir-associated renal dysfunction is difficult to study in humans because it occurs in patient populations who are generally receiving multiple medicines concurrently and dysfunctions occur infrequently. We studied the effects of two regimens of acyclovir treatment, a short-term high dose (210 mg/kg/day for 43 hr) via constant infusion and a chronic lower dose by intermittent infusion (15 mg/kg, 3 times/day for 28 days), on selected renal functions in dogs. Urine concentrating capacity as compared to base-line and controls declined during both the short-term (40% decline) and chronic treatments (36% decline). The persistence of the concentrating deficit in the presence of stimulation with vasopressin suggested that the defect resided in the renal response to vasopressin. Glomerular filtration rates significantly decreased during the acute high-dose treatment (from 104 +/- 15 to 87 +/- 11 ml/min) but not during the chronic low-dose treatment. Both acyclovir treatments were associated with a small but significant decline (approximately 10% for both studies) in the plasma potassium concentrations although an increase in urine potassium clearance could not be demonstrated. We conclude that acyclovir can cause renal dysfunction in healthy animals at plasma concentrations higher but comparable to those achieved clinically. Although both treatment regimens decreased renal function, the shorter high-dose regimen which maintained acyclovir plasma concentrations was more detrimental than the longer exposure to a lower dose of the drug given intermittently. The data suggest that renal dysfunction is not related to a rare sensitivity, as all acyclovir-treated animals showed subtle decrements in renal function.

Antiviral and antigenic properties of recombinant porcine interferon gamma

Recombinant porcine interferon gamma (rPoIFN gamma) induced a dose-dependent inhibition of the cytopathic effect produced by vesicular stomatitis virus (VSV) challenge of both homologous and heterologous (bovine) cell lines. In addition, an antiviral effect of rPoIFN gamma was demonstrable against the coronavirus transmissible gastroenteritis virus (TGEV) infection of porcine epithelial cells and of pulmonary macrophages. A rabbit anti-PoIFN gamma antiserum was prepared and shown to specifically neutralize the antiviral effects of natural and recombinant porcine IFN gamma preparations. This antiserum could also neutralize recombinant bovine IFN gamma but not recombinant human IFN gamma. These results suggest antigenic homology of porcine and bovine IFN gamma but antigenic differences between these molecules and human IFN gamma.

Recombinant bovine interferon-alpha I 1 inhibits the migration of lymphocytes from lymph nodes but not into lymph nodes

Recombinant bovine interferon-alpha I 1 (IFN-alpha) was tested for effects on lymphocyte migration into and out of the lymph nodes of sheep. Chronic lymph drainage methods were used to monitor the efferent lymph of single lymph nodes of unanaesthetized animals. When IFN-alpha was injected into the drainage area of the lymph node, infused directly via an afferent lymphatic, or injected intravenously, a marked decrease in cell output was observed. Nanogram quantities of IFN-alpha produced an effect that lasted several hours. To test whether this effect was specific for lymphocytes, we first stimulated a lymph node with Staphylococcus aureus so that large numbers of neutrophils and lymphocytes were present in efferent lymph. When IFN-alpha was then injected, the lymphocytes disappeared from efferent lymph but the neutrophils did not. Normal efferent lymph cells were labeled with radioisotopes and injected intravenously during the IFN-alpha induced effect. The entry of lymphocytes from the blood was significantly enhanced at a time coinciding with the suppressed cell exit in the efferent lymph. Recovery data indicated that the lymphocytes were retained temporarily in the lymph node but were not destroyed. Furthermore, the bovine IFN-alpha does not appear to be conspicuously antigenic in sheep. It is not yet certain whether IFN-alpha enhances the interactions of cells within the lymph node thereby potentiating immunologic reactions.

Non-invasive assessment of left internal mammary-coronary bypass patency using the external Doppler probe

Non-directional blood velocity of left internal mammary bypass grafts was non-invasively studied with the Doppler ultrasonic probe. Thirteen of 14 subjects had angiographic evidence of bypass graft patency and their Doppler signals demonstrated high amplitude phasic blood velocities. A single patient with proximal left internal mammary arterial graft occlusion manifested marked attenuation of Doppler blood velocity signals. It is concluded that this technic offers a potential for ambulatory and in-office screening of internal mammary artery bypass graft function.