Effects of extracellular Ca2+ on phagocytosis and intracellular Ca2+ concentrations in polymorphonuclear leukocytes of postpartum dairy cows.
The aim of this study was to determine the effects of extracellular Ca(2+) concentration ([Ca(2+)](e)) on phagocytosis and intracellular Ca(2+) concentration ([Ca(2+)](i)) in bovine polymorphonuclear leukocytes (PMNs). The experiments were performed by using blood samples from parturient paretic and clinically normal parturient cows and manipulating the [Ca(2+)](e) in vitro. Phagocytosis by PMNs (with and without stimulation with phorbol myristate acetate and inhibition with cytochalasin B) and resting [Ca(2+)](i) were significantly lower in parturient paretic cows. Repletion of Ca(2+) in the extracellular media for the samples from these animals increased phagocytosis and resting [Ca(2+)](i). In the blood of clinically normal parturient cows, decreasing the [Ca(2+)](e) decreased phagocytosis and resting [Ca(2+)](i) in PMNs, but increasing the [Ca(2+)](e) did not affect phagocytosis. These results suggest that the hypocalcemic condition of parturient paretic cows in vivo causes decreased phagocytosis and resting [Ca(2+)](i) in PMNs, which may partly contribute to greater susceptibility to infection.
Ducusin
R J T
RJ
Department of Veterinary Clinical Science, The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan. rjducusin@euroramail.com
Uzuka
Y
Y
Satoh
E
E
Otani
M
M
Nishimura
M
M
Tanabe
S
S
Sarashina
T
T
D000276:Adjuvants, Immunologic / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism*; D002417:Cattle; D002418:Cattle Diseases / Q000097:blood / Q000276:immunology*; D003571:Cytochalasin B / Q000378:metabolism; D005260:Female; D009504:Neutrophils / Q000276:immunology* / Q000378:metabolism; D010319:Parturient Paresis / Q000097:blood / Q000276:immunology; D010587:Phagocytosis / Q000276:immunology*; D049590:Postpartum Period / Q000097:blood / Q000276:immunology; D011247:Pregnancy; D013755:Tetradecanoylphorbol Acetate / Q000378:metabolism
D000276:Adjuvants, Immunologic; D003571:Cytochalasin B; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium