Some observations on the effects of age of calves on the phagocytosis and killing of Staphylococcus aureus by polymorphonuclear leucocytes

Immunological, hematological, biochemical, and histopathological studies on cows naturally infected with lumpy skin disease

AIM

Lumpy skin disease (LSD) is an infectious viral disease of cattle caused by LSD virus (LSDV) of the family Poxviridae characterized by skin nodules covering all parts of the body. There are many aspects of LSD remaining unknown, thus immunological, hematological, and biochemical parameters were estimated.

MATERIALS AND METHODS

During an outbreak of LSD in Sharkia governorate from Egypt, 211 cows aging (2-4 years) were examined clinically for the presence of LSD lesions during the period from July to November 2014. A total of 134 cows from those showed lesions suspected to be LSD.

RESULTS

Recorded clinical signs were pyrexia with the development of skin nodules of varying sizes which ranged from a few to several hundred sometimes coalesced together. Enlargements of the peripheral lymph nodes. Intracytoplasmic inclusion bodies were noticed in the histopathological examination. Immunological studies revealed a significant decrease of lymphocyte transformation rate, phagocytic % and killing % which was marked within 2 weeks postinfection. LSD resulted in non-significant in hemogram in 1(st)-2(nd) day post-infection while a macrocytic hypochromic anemia within 10-14(th) days post-infection. Leucopenia and lymphopenia were recorded 1(st)-2(nd) day post-infection while at 10-14(th) showed granulocytic leucocytosis. Biochemical analysis revealed hypoproteinemia, hypoalbuminemia, and hyperglobulinemia especially gamma globulins. There were a significant increase in serum alanine aminotransferase, aspartate aminotransferase activities, creatinine level, blood urea nitrogen and creatine phosphokinase.

CONCLUSION

LSDV infected cows in early stages revealed leucopenia. Immunosuppressive effect was pronounced later. In late stage revealed hemolytic anemia, leucocytosis and increase of serum CK, which could aid in diagnosis. Disturbance in liver and kidney function tests have been occurred.

Variability of neutrophil and pulmonary alveolar macrophage function in swine

Neutrophils and alveolar macrophages are essential defence mechanisms against bacterial infection of the lung. The purpose of this study was to evaluate the variability of a panel of neutrophil and alveolar macrophage function assays in swine, and to determine if the function of these leukocytes differed at various stages of production. Measured neutrophil functions included chemotaxis, phagocytosis, oxidative burst, and degranulation. Phagocytosis and oxidative burst were measured in alveolar macrophages isolated from bronchoalveolar lavage fluid (BALF). Both neutrophil and alveolar macrophage functions were highly variable from day-to-day and between pigs. Individual pigs did not have consistently high or low neutrophil and macrophage responses over time when compared to their cohorts. Older grower-finisher pigs had significantly greater neutrophil oxidative burst responses than younger suckling and weaner pigs (P < 0.001). Similarly, alveolar macrophages from suckling and early weaner pigs less than 40 days of age had significantly lower oxidative burst responses than those from older pigs (P = 0.02). Age-related variation in phagocytosis, chemotaxis, or granule secretion were not detected. These results establish baseline data for individual and age-related variation in swine leukocyte function, and form a basis for further evaluation of the contribution of non-infectious factors to development of the porcine respiratory disease complex.

Influence of age of the donor sheep on the phagocytosis of Staphylococcus aureus subspecies anaerobius and S aureus by neutrophils

The age of the sheep donating neutrophils had a marked influence in vitro on their phagocytic ability with respect to Staphylococcus aureus and S aureus subspecies anaerobius. Neutrophils from lambs five to eight weeks old phagocytosed these organisms significantly less efficiently (P < 0.001) than neutrophils from adults two to four years old. However, neutrophils from the young animals phagocytosed S aureus significantly (P < 0.001) better than S aureus subspecies anaerobius (61.5 v 53.8 per cent), whereas there was no significant difference in the ability of the neutrophils from adult sheep to phagocytose S aureus and S aureus subspecies anaerobius (68.2 v 68.2 per cent).

Comparative in vitro phagocytosis and F-actin polymerization of bovine neonatal neutrophils

Analysis of neonatal neutrophil (PMN) functions should help to reveal factors which could contribute to the impaired host defense system of neonates. We analysed functional parameters of PMN from newborn calves (N-PMN) and adult bovines (A-PMN): cellular volume and F-actin content upon stimulation with complement factors, by cytofluorometry and phagocytosis of E. coli 78:80B with a colorimetric assay. Polymerization of F-actin was rapid in both N- and A-PMN, but reached higher levels in N-PMN. N-PMN are significantly smaller than A-PMN throughout the whole activation time. Percentage of phagocytosing PMN, the rate of phagocytosis, and the rate of killing are similar between A- and N-PMN after opsonization of bacteria with adult serum (AS). Opsonization with newborn serum (NS) reduced all three examined parameters: in A-PMN more (P < 0.001) than in N-PMN (P < 0.05). However, when phagocytosis was compared following age-matched opsonization (N-PMN and NS; A-PMN and AS), N-PMN phagocytosed less (P < 0.001) bacteria per PMN than A-PMN. Additionally, steroidal (dexamethasone) and non-steroidal (phenylbutazone) anti-inflammatory drugs inhibited phagocytosis by N-PMN less than by A-PMN. Higher relative F-actin content of N-PMN can be correlated with the documented functional hyperactivity of bovine N-PMN. However, the exaggerated impairment of phagocytosis in calves observed after age-matched opsonization of bacteria could potentially indicate a specific host defence defect.