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in American Journal of Veterinary Research

Summary

The prophylactic/therapeutic activity of natural bovine fibroblast interferon (BoF-ifn) against bovine rhinovirus infection in calves was assessed. Six calves were each given 8 intranasal inoculations of partially purified BoF-ifn (3.25 × 105 U at 8 am, 11 am, 5 pm, and 8 pm on day 1 and 8 am, 11 am, 2 pm, and 5pm on day 2), and 6 calves were given placebo. All calves were challenge exposed with 105.1 TCID 50) of bovine rhinovirus after the first 2 treatments (6 hours after the first ifn or placebo treatment). Nasal excretion of rhinovirus, ifn concentration in the nasal secretions, and nasal secretion and serum rhinovirus antibodies were measured before and at selected times after calves were inoculated. Interferon-treated calves excreted rhinovirus in their nasal secretions in lesser amounts (mean value, 0.84 log10 TCID 50/ml vs 1.58 log10 TCID 50/ml on postchallenge exposure days 1 and 2; (P < 0.05) and for a shorter duration (P < 0.05) than did placebo-treated calves. No calves developed clinical signs of respiratory tract illness. Rhinovirus antibody titer was not significantly different between ifn- and placebo-treated calves.

Free access
in American Journal of Veterinary Research

Summary

Newborn pups from 4 large litters were allotted to 6 groups to determine effect of time and route of administration on absorption of an alternate source of immunoglobulin. Selective absorption of specific classes of immunoglobulins was also investigated. The alternate source of immunoglobulin consisted of pooled serum that was administered either po or sc. Control groups were either left with the dam (group C1) or fed milk replacer (group C2). Blood samples were collected from pups at birth and 24 hours. Immunoglobulin (IgA, IgG, IgM) concentrations were determined by use of radial immunodiffusion on samples of pooled serum, colostrum, and pups’ serum (birth and 24 hours).

Serum IgA concentration was less than the sensitivity of the procedure and was not included in the statistical analysis. Pups fed 8 ml of pooled serum at birth and 12 hours later (group T1) absorbed more (P< 0.05) IgG and IgM than did group-C2 pups, but less (P < 0.05) than did group-C1 pups. Pups fed 8 ml of pooled serum at 12 hours only had significant (P < 0.05) increase of IgG concentration, but no absorption of IgM (P > 0.05) at 24 hours, compared with control pups (group C2). Pups administered 8 ml of pooled serum SC at birth (group SC1) had similar (P > 0.05) absorption of IgG and higher (P < 0.05) absorption of IgM than did pups of group T1. Pups administered 16 ml of pooled serum sc at birth had the highest increase of IgG and IgM concentrations of all treatment groups, but immunoglobulin concentrations were lower (P < 0.05) than those for group-C1 pups. Absorption of IgG was favored, compared with IgM, when pooled serum was fed.

Results indicate clearly that intestinal absorption of immunoglobulins is minimal after 12 hours and thus, another route of administration should be used. Pups in groups SC1 and T1 had similar absorption of IgG, despite lower IgM absorption in pups of group T1. This lower IgM concentration in group-T1 pups may have been the result of selective intestinal absorption or the consequence of low number of pups per group. Subcutaneous administration of 16 ml of pooled serum was the most successful alternative to colostrum, with minimal pain to pups if serum was administered slowly. Serum IgG concentration in Cl pups was higher than expected and probably was attributable to the amount of colostrum available to the pups.

Free access
in American Journal of Veterinary Research

Summary

We examined the effect of infusion of lipopolysaccharide (lps) on serum tumor necrosis factor alpha (tnfα) concentration and clinical attitude in 2- to 3-day-old colostrum-fed (cf) and colostrum-deprived (cd) foals. Eleven cf and 8 cd neonatal foals were given a bolus IV infusion of Escherichia coli O55:B5 lipopolysaccharide (0.5 µg kg of body weight) in sterile saline (0.9% NaCl) solution. Four cf and 2 cd foals were given saline solution alone. Serum IgG concentration and serum anti-lps IgG(T) antibody titer were determined for each foal prior to infusion. A depression index was used to score clinical abnormalities. Serum tnfα concentration was estimated by use of an in vitro cytotoxicity bioassay that used WEHI 164 clone 13 cells as targets. The cytotoxic serum factor was identified as tnfα by immunoprecipitation with caprine antisera raised against the 15 NH2- terminal amino acids of human tnfα. Tumor necrosis factor alpha was not detected in any preiniusion serum samples nor in any samples from foals given saline solution alone. Serum tnfα concentration increased in all lps-infused foals and peaked between 60 and 90 minutes after infusion. Serum tnfα concentrations, expressed as mean percentage of peak serum tnfα concentration, persisted longer in cd foals given lps than in cf foals given lps. All lps-infused foals displayed clinical signs of endotoxemia, but mean depression index scores of the cf and cd foals given lps were not significantly different at any time. Serum tnfα concentrations were correlated with depression index scores in both lps-infused groups. Mean rectal temperature increased by 1 hour and remained high for 4 hours after infusion in cf foals given lps . Mean rectal temperature in cd foals given lps was significantly less than that for cf foals given lps 1 and 2 hours after infusion and was higher than mean rectal temperature prior to infusion 3 and 4 hours after infusion. Neither preinfusion total serum IgG concentration nor serum anti-lps IgG(T) antibody titer correlated with peak serum tnfα concentration in the 19 lps-infused foals.

Free access
in American Journal of Veterinary Research

Summary

Serum interleukin-6 (il-6) concentration was measured in 11 colostrum-fed (cf) and 8 colostrum-deprived (cd) 2- to 3-day-old foals after foals were infused with lipopolysaccharide (lps; Escherichia coli O55:B5 endotoxin, 0.5 µ.g/kg of body weight in sterile saline [0.9% NaCl] solution). Four cf and 2 cd foals were given saline solution alone. Serum il-6 concentration was estimated by use of an in vitro proliferative bioassay, using the IL-6 dependent B.13.29 clone 9 cells. Interleukin-6 concentration increased in all lps-infused foals, and geometric mean serum il- 6 concentration was significantly higher in cf than cd foals 30 and 90 minutes after infusion. Both lps- infused groups had multiple spikes of mean il-6 concentration that peaked at 120 minutes in cf foals and 150 minutes in cd foals. Results indicated that il-6 is produced in neonatal foals in response to lps infusion. Furthermore, colostrum deprivation resulted in longer times to peak mean serum il-6 concentration and tended to reduce serum il-6 concentration in neonatal foals.

Free access
in American Journal of Veterinary Research
Full access
in Journal of the American Veterinary Medical Association