Neutrophil function and plasma opsonic capacity in colostrum-fed and colostrum-deprived neonatal kittens.
OBJECTIVE
To determine whether passive transfer of IgG in neonatal kittens affects plasma opsonic capacity and neutrophil phagocytic and oxidative burst responses to bacteria in vitro.


METHODS
22 kittens from 6 specific pathogen-free queens.


METHODS
Kittens were randomized at birth into the following treatment groups: colostrum-fed, colostrum-deprived, or colostrum-deprived supplemented with feline or equine IgG. Blood samples were collected at intervals from birth to 56 days of age. Plasma IgG concentrations were determined by radial immunodiffusion assay. Neutrophil function was assessed by a flow cytometry assay providing simultaneous measurement of bacteria-induced phagocytosis and oxidative burst. The opsonic capacity of kitten plasma was determined in an opsonophagocytosis assay with bacteria incubated in untreated or heat-inactivated plasma.


RESULTS
Among treatment groups, there were no significant differences in neutrophil phagocytic and oxidative burst responses to bacteria or opsonic capacity of plasma. In all samples of plasma, inactivation of complement and other heat-labile opsonins significantly reduced the opsonic capacity. Plasma IgG concentrations in kittens did not correlate with neutrophil function or plasma opsonic capacity before or after inactivation of complement.


CONCLUSIONS
The plasma opsonic capacity and neutrophil phagocytic and oxidative burst responses in vitro of kittens receiving passive transfer of IgG via colostrum intake or IgG supplementation and those deprived of colostrum were similar. The alternate complement pathway or other heat-labile opsonins may be more important than IgG in bacterial opsonization and phagocytosis.
Hanel
Rita M
RM
Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA.
Crawford
P Cynda
PC
Hernandez
Jorge
J
Benson
Neal A
NA
Levy
Julie K
JK
D000818:Animals; D000831:Animals, Newborn; D000833:Animals, Suckling / Q000276:immunology*; D002415:Cats; D003126:Colostrum / Q000276:immunology*; D007074:Immunoglobulin G / Q000097:blood; D009504:Neutrophils / Q000276:immunology*; D009895:Opsonin Proteins / Q000097:blood* / Q000276:immunology*; D010587:Phagocytosis; D016897:Respiratory Burst
D007074:Immunoglobulin G; D009895:Opsonin Proteins