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Opsonisation and neutrophil phagocytosis in foals and adult horses

Gröndahl, Gittan (2001). Opsonisation and neutrophil phagocytosis in foals and adult horses. Diss. (sammanfattning/summary) Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae. Veterinaria, 1401-6257
ISBN 91-576-5931-1
[Doctoral thesis]

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Infectious diseases are the main cause of disease and deaths in foals. The neutrophil phagocyte is a part of the early, non-specific immune response, which is essential in defending the host against microbial invasion. Coating of microbes with opsonic factors such as antibodies and complement from serum is required for optimal phagocytosis.Flow cytometric methods were developed and used for studies of equine neutrophil phagocytosis and serum opsonisation of Saccharomyces cerevisiae, Escherichia coli and Actinobacillus equuli, and of the expression of complement receptor subunit CD18 on neutrophils. Foals from birth to 2 months of age and adult horses were studied.Incubation for 15 min was found sufficient for both opsonisation and phagocytosis. Opsonisation of yeast and A. equuli, but not of E. coli, was observed already at low serum concentrations (Complement activation was needed for optimal phagocytosis of all the microbes studied. The classical pathway was required for yeast phagocytosis at low serum concentrations (1.5%) and is the main pathway for C3 deposition with In newborn foals, colostrum ingestion was required to achieve a serum opsonic capacity for all the microbes studied. Serum from foals up to 3-4 weeks of age showed a lower capacity to opsonise yeast, but a higher capacity to opsonise E. coli compared to serum from older foals and horses. No age-related differences were observed in serum opsonisation ofA. equuli. Very low serum concentrations of IgG or IgGb were associated with decreased phagocytosis of yeast and E. coli, but not of A. equuli. However, there were large individual variations in the opsonisation of yeast, irrespective of the concentrations of IgG, by sera from newborn foals and plasma from individual adult donors. This may have been due to different levels of complement activation. Plasma transfusion to healthy 7-day old foals resulted in an increased serum capacity for yeast opsonisation at 14 days.The neutrophil phagocytosis capacity per se was similar in foals and adult horses, and the expression of complementreceptor CD18 was also similar, or higher in the foals.These results emphasise the importance of both antibodies and complement factors in serum for an effective defence against microorganisms in young foals. Intravenous administration of plasma to foals seems to be of some benefit, but additional studies are warranted to characterise the factors involved. Important differences were observed between various microbes in the particular requirements for effective phagocytosis.The involvement of complement in common equine pathological conditions deserves further attention. A better understanding of the equine complement system may lead to improved prophylactic and therapeutic regimens in foals and adult horses.

Authors/Creators:Gröndahl, Gittan
Title:Opsonisation and neutrophil phagocytosis in foals and adult horses
Series Name/Journal:Acta Universitatis Agriculturae Sueciae. Veterinaria
Year of publishing :2001
Number of Pages:69
Publisher:Swedish University of Agricultural Sciences
ISBN for printed version:91-576-5931-1
Publication Type:Doctoral thesis
Article category:Other scientific
Version:Published version
Full Text Status:Public
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 403 Veterinary Science > Clinical Science
Keywords:neutrophil, phagocytosis, opsonisation, foals, complement, IgG, transfusion, Escherichia coli, Actinobacillus equuli, colostrum, flow cytometry
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ID Code:28380
Faculty:VH - Faculty of Veterinary Medicine and Animal Science
Department:(VH) > Institutionen för kirurgi och medicin, Stordjur (970101-040630)
Deposited By: SLUpub Connector
Deposited On:17 Jun 2022 11:25
Metadata Last Modified:17 Jun 2022 11:31

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