Intramuscular Administration of a Synthetic CpG-Oligodeoxynucleotide Modulates Functional Responses of Neutrophils of Neonatal Foals

Neutrophils play an important role in protecting against infection. Foals have age-dependent deficiencies in neutrophil function that may contribute to their predisposition to infection. Thus, we investigated the ability of a CpG-ODN formulated with Emulsigen to modulate functional responses of neutrophils in neonatal foals. Eighteen foals were randomly assigned to receive either a CpG-ODN with Emulsigen (N = 9) or saline intramuscularly at ages 1 and 7 days. At ages 1, 3, 9, 14, and 28, blood was collected and neutrophils were isolated from each foal. Neutrophils were assessed for basal and Rhodococcus equi-stimulated mRNA expression of the cytokines interferon-γ (IFN-γ), interleukin (IL)-4, IL-6, and IL-8 using real-time PCR, degranulation by quantifying the amount of β-D glucuronidase activity, and reactive oxygen species (ROS) generation using flow cytometry. In vivo administration of the CpG-ODN formulation on days 1 and 7 resulted in significantly (P<0.05) increased IFN-γ mRNA expression by foal neutrophils on days 3, 9, and 14. Degranulation was significantly (P<0.05) lower for foals in the CpG-ODN-treated group than the control group at days 3 and 14, but not at other days. No effect of treatment on ROS generation was detected. These results indicate that CpG-ODN administration to foals might improve innate and adaptive immune responses that could protect foals against infectious diseases and possibly improve responses to vaccination.The open access fee for this work was funded through the Texas A&M University Open Access to Knowledge (OAK) Fund

Macrolide- and Rifampin-Resistant Rhodococcus equi on a Horse Breeding Farm, Kentucky, USA

Macrolide and rifampin resistance developed on a horse breeding farm after widespread use was instituted for treatment of subclinical pulmonary lesions in foals. Resistance occurred in 6 (24%) of 25 pretreatment and 8 (62%) of 13 (62%) posttreatment isolates from affected foals. Drug-resistant isolates formed 2 distinct genotypic clusters

Effects of Location for Collection of Air Samples on a Farm and Time of Day of Sample Collection on Airborne Concentrations of Virulent \u3cem\u3eRhodococcus equi\u3c/em\u3e at Two Horse Breeding Farms

Objective: To determine whether airborne concentrations of virulent R equi varied by housing location, time of day, and month (February through July) at 2 horse breeding farms. Sample Population: 2 farms with recurrent R equi foal pneumonia in central Kentucky. Procedures: From February through July 2008, air samples were collected hourly for a 24-hour period each month from stalls and paddocks used to house mares with foals. Virulent concentrations of airborne R equi were determined using a colony immunoblot technique and differences were compared using zero-inflated negative binomial methods to determine effects of location, time, and month. Results: The presence of mares and foals at the sampling site significantly (P = 0.017) modified the effect of location (stall versus paddock) by increasing airborne concentrations of virulent R equi. Relative to the period from midnight through 5:59 AM, airborne concentrations of virulent R equi were significantly (P = 0.016) higher between 6:00 PM through 11:59 PM midnight. There were no significant differences in airborne concentrations between farms or among months. Conclusions: Airborne concentrations of virulent R. equi were significantly increased by sampling when horses were predominately housed in the sampling site area (ie, higher in stalls when horses were predominately stalled, and higher in paddocks when horses were predominately in paddocks). For ecological and epidemiological studies, there appears to be no difference in airborne concentrations of virulent R. equi among air samples collected between the hours of 6:00 AM and midnight

Mean (and 95% confidence intervals) for neutrophil parameters determined using flow cytometry (please see text for details) and estimated by mixed-effects modeling.

<p>Values in columns with the same letter indicate absence of statistical significance between groups for a given age. Values in rows with differing superscripted numbers indicate significant (P<0.05) differences among ages within group.</p><p>Mean (and 95% confidence intervals) for neutrophil parameters determined using flow cytometry (please see text for details) and estimated by mixed-effects modeling.</p

Boxplots of log₁₀ values of mRNA copy numbers by age and treatment group: blue boxes are data from the control (saline) group and red boxes are data from the CpG-treated foals.

<p>The triangles in the middle of boxes represent the median value; the bottom and top of the boxes represent the 25^th and 75^th percentiles, respectively. The vertical lines extending from the boxes to horizontal lines represent multiples of 1.75 of the respective interquartile distance. Numbers above boxes represent within-treatment group differences among ages: within treatment group, ages with different numbers differed significantly (P<0.05) between groups. Asterisks denote days on which values were significantly (P<0.05) different between the control and Cp-G-treated foals. Arrows along the horizontal axis indicate ages when treatment (saline or CpG) was administered.</p

Mean (and 95% confidence intervals) for mRNA copy numbers estimated by mixed-effects modeling for IL-4, IL-6, and IL-8.

<p>Data represent back-transformed results of log₁₀-transformed data. Values in columns with the same letter indicate absence of statistical significance between groups for a given age. Values in rows with differing superscripted numbers indicate significant (P<0.05) differences among ages within group.</p><p>Mean (and 95% confidence intervals) for mRNA copy numbers estimated by mixed-effects modeling for IL-4, IL-6, and IL-8.</p

Boxplots of values of liberated 4-methylumbelliferone (4-MU) measured fluorometrically by age and treatment group: blue boxes are data from the control (saline) group and red boxes are data from the CpG-treated foal (see <b>Figure 1</b> for boxplot description).

<p>Numbers above boxes represent within-treatment group differences among ages: within treatment group, ages with different numbers differed significantly (P<0.05) between groups. Asterisks denote days on which values were significantly (P<0.05) different between the control and Cp-G-treated foals. Arrows along the horizontal axis indicate ages when treatment (saline or CpG was administered.</p