Immunoglobulin isotypes in sera and nasal mucosal secretions and their neonatal transfer and distribution in horses.
OBJECTIVE
To determine concentrations of IgA and IgG subclasses in serum, colostrum, milk, and nasal wash samples of adult horses and foals.


METHODS
Seven 2-year-old Welsh ponies, 27 adult mixed-breed horses, and 5 Quarter Horse mares and their foals.


METHODS
Serum was obtained from ponies and adult horses. Colostrum and milk were obtained from mares and serum and nasal wash samples from their foals immediately after parturition and on days 1, 7, 14, 28, 42, and 63. Nasal wash samples were also obtained from 23 adult horses. Concentrations of immunoglobulins were determined by use of inhibition ELISA. To determine transfer of maternal isotypes to foals, concentrations in colostrum and milk were compared with those in foal serum. Serum half-lives of isotypes in foals were also determined.


RESULTS
IgGb was the most abundant isotype in serum and colostrum from adult horses, whereas IgA was the predominant isotype in milk. The major isotype in nasal secretions of adult horses and foals > or = 28 days old was IgA, but IgGa and IgGb were the major isotypes in nasal secretions of foals < or = 14 days old. Serum half lives of IgGa, IgGb, IgG(T), and IgA in foals were 176, 32, 21, and 3.4 days, respectively.


CONCLUSIONS
The early immunoglobulin repertoire of neonatal foals comprised IgGa, IgG(T), and IgA; endogenous synthesis of IgGb could not be detected until 63 days after birth. The restricted repertoire of immunoglobulins in foals may influence humoral immune responses to vaccination.
Sheoran
A S
AS
Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington 40546-0099, USA.
Timoney
J F
JF
Holmes
M A
MA
Karzenski
S S
SS
Crisman
M V
MV
D000818:Animals; D000831:Animals, Newborn / Q000276:immunology*; D000911:Antibodies, Monoclonal / Q000032:analysis; D003126:Colostrum / Q000737:chemistry; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005260:Female; D006736:Horses / Q000276:immunology*; D007116:Immunization, Passive / Q000662:veterinary*; D007070:Immunoglobulin A / Q000032:analysis; D007074:Immunoglobulin G / Q000032:analysis; D007132:Immunoglobulin Isotypes / Q000032:analysis* / Q000097:blood; D008297:Male; D008892:Milk / Q000737:chemistry; D009297:Nasal Mucosa / Q000276:immunology / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007132:Immunoglobulin Isotypes