In vitro assay for phagocytic activity by canine neutrophils for <i>Escherichia coli</i>

Abstract

INTRODUCTION (Gershwin et al., 1995). A deficiency or a malfunction at any stage of neutrophil function can impair the ability of The Innate immunity is the first line of defense in the an animal to overcome an infection (Gershwin et al., body which includes physical and chemical barriers; 1995). Severe sepsis in diseases may alter innate circulating effector cells [phagocytes and natural killer imm une def ens es, dis rup t mic rob ial cle ara nce cells (NK)], complement proteins and cytokines (Abba, mechanisms, and complicate the pathophysiology of 2007). Intact skin and its secretions are impermeable to sepsis. Septic shock itself has significant effects upon most infectious agents and act as major physical barriers the innate and adaptive host immune responses ge ne ra ti ng th e fi rs t li ne of de fe ns e. T ho se contributing to a state of sepsis-induced immune microorganisms that evade the epithelial barrier get dysregulation (Opal and Cross, 2005). Although killed by natural antimicrobial peptides, but many get congenital or inherited immunodeficiency disorders are engulfed and killed by phagocytes (Tizard, 2009; Roitt, uncommon in the dog, immunodeficiency secondary to 1988). Phagocytosis is an active process in phagocytic a wide range of causes (e.g., age, drug therapy, and le uk oc yt es , na me ly, ne ut ro ph il s, eo si no ph il s, chronic neoplastic or infectious disease) is relatively monocytes, and macrophages. Neutrophils are the first comm on in adul t dogs. Most cani ne immu ne resp onde rs th at ph agoc ytiz e and kill inva ding deficiencies are breed-related. Aged Beagle dogs have pathogens (Abba, 2007). Phagocytosis of cytokine decreased neutrophil phagocytosis and neutrophilactivated neutrophils and their microbicidal activities related gene expression compared to younger dogs are the first line of cellular defense against invading (Hall et al., 2010) pathogens, and are a major part of innate immunity Neutrophil phagocytosis can be measured by several (Silva et al. 1988). methods by allowing bacteria, yeast, or other particles Phagocytic activity is a continuous process involving and neutrophils to interact, and then to measure the discrete stages occurring in a sequential manner, number of neutrophils that have ingested particles, as namely, cell activation, chemotaxis, adherence, well as the phagocytic index determined by the average ingestion, and destruction (Tizard, 2009). The factors number of organisms within a phagocyte (Kaneko and influencing phagocytic properties of cells include cell Harvey, 1997; Gershwin et al., 1995). A phagocytosis age, energy (ATP), and integrity of cellular skeleton assay of canine blood neutrophils for bacteria is a long such as microfilaments and microtubules (Jain, 1986). felt need to identify immune compromised dogs. The The important properties of bacteria influencing objective of this research was to establish an in vitro ph ag oc yt os is ar e su rf ac e ch ar ge s, ce ll wa ll phagocytic assay for blood neutrophils isolated from composition, capsu...