IgG antibody testing method

Details IgG antibody testing method IgG antibody testing method

1998-09-11

2001-06-12

Chin, Christopher L. (Department: 1641)

Chemistry: analytical and immunological testing

Involving an insoluble carrier for immobilizing immunochemicals

C422S051000, C422S051000, C422S051000, C435S970000, C435S805000, C435S810000, C436S513000, C436S514000, C436S524000, C436S530000, C436S169000, C436S805000, C436S810000

Reexamination Certificate

active

06245577

ABSTRACT:

CROSS-REFERENCE TO RELATED APPLICATIONS
Not Applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable.
AUTHORIZATION PURSUANT TO 37 C.F.R. §1.71 (d) (e)
A portion of the disclosure of this patent document, including appendices, may contain material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to immunoglobulin testing methods and more particularly to a method of determining the concentration of IgG antibodies in biological fluids of mammals.
2. Description of the Related Art
The numbers in brackets refer to the publications listed in the Appendix, the teachings of which are incorporated herein by reference.
The bovine immunoglobulin system closely resembles that of other species with respect to physiochemical properties and nomenclature. Well characterized classes include IgG, IgM [
13
],IgA [
14
] and IgE [
15
-
17
]. The IgG class contains two documented subclasses, IgG
1
and IgG
2
, which have antigenic differences in the Fc portion of the heavy chain. A possible third subclass, IgG
3
, has been reported [
18
], but remains unconfirmed. It is presumed that additional heterogeneity awaits discovery.
In cattle, the newborn calves are virtually devoid of any detectable levels of immunoglobulin [
19
,
20
]. This is due to a syndesmochorial type placental attachment, which restricts the transfer of maternal immunoglobulins to fetal blood. Essentially, the neonatal calf relies entirely on passive immunity for it's immune protection during the first weeks of life. This transfer of IgG is important in reducing mortality in calves [
1
,
2
,
4
]. Stress from birthing, temperature, or herd management practices are factors that may adversely affect the passive transfer of IgG [
7
-
8
].
Frequently, colostral supplements are included in calf rations to ensure that adequate amounts of IgG are provided [
3
,
5
,
6
]. These supplements include either frozen or natural colostrum, and/or commercial supplements. Although feeding fresh or stored colostrum seems simple, obtaining and storing adequate amounts of quality colostrum is often difficult and laborious. Additionally, the high cost of commercial colostrum prohibits its use on a routine basis. From a herd management aspect, there would be a tremendous time and monetary savings if only those animals in need of the colostral supplement could be identified quickly and accurately.
In order to assess the passive transfer of maternal immunoglobulin, serum IgG concentrations of neonatal calves may be measured. Historically, the measurement of bovine serum IgG has been performed by several methods. These methods can be divided into three main groups [
21
]:
a.) Accurate tests for immunoglobulin, which may or may not provide a rapid result. For these methods, blood samples must be shipped to, and analyzed in the laboratory and require professional training and equipment [
12
,
20
].
b.) Tests which can be done in a relatively short time on the farm and under “field” conditions, and do not require much training or equipment. These tests however are qualitative in nature and are not accurate. This group includes the glutaraldehyde test, the zinc sulfate turbidity test and the determination of total protein by refractometry.
c.) Tests based upon proteins other than IgG. This includes testing for &ggr;-glutamyltransferase, a serum enzyme whose concentration has been reported to correlate with total globulin levels [
21
]. This method has never been well accepted.
It is generally recommended that calves receive a minimal dose of 100 g of immunoglobulin at birth [
9
,
10
]. Calf serum IgG concentrations greater than or equal to 10 mg/ml indicates adequate passive transfer [
10
,
11
]. Values less than 10 mg/ml are considered to be indicative of Failure of Passive Transfer (FPT). It is widely accepted that the treatment for FPT is to administer two feedings of colostrum (50 g IgG/L), one within the first 24 hours of birth and the second 12 hours later. Treatment at times outside this window tend to be less effective due to the decrease in permeability of the calf intestine to ingested antibodies.
Those concerned with these and other problems recognize the need for fast, accurate and simple assay for IgG.
BRIEF SUMMARY OF THE INVENTION
The present invention provides a method of determining the concentration of IgG antibodies in the biological fluids of mammals. The assay may be performed in a lateral flow cassette or dipstick format where dehydrated immobilized reagents are spaced along a membrane. A sample of a mammalian biological fluid is exposed first to an IgG complexing agent to yield a conjugate. The conjugate then moves along the membrane and is exposed to a standard mammalian IgG applied to the membrane at a test position. Binding of the IgG is indicated by a color change at the test position on the membrane. A control reagent of dehydrated anti-IgG complexing agent may be applied to the membrane at the control position spaced downstream from the test position. Interaction of the IgG complexing agent with the anti-IgG complexing agent forms a visible line at the control position on the membrane.
Therefore, an object of the present invention is the provision of an improved IgG antibody testing method.


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Thomas E. Besser, DVM.Phd, & Clive C. Gay, DVM.MVSc, FACVS; The Importance of Colostrum to the Health of the Neonatal Calf; Mar. 1994; vol. 10-No. 1, pp. 107-117; Washington State University College of Veterinary Medicine, Pullman, Washington.
T. E. Besser and C.C. Gay; Colostral Transfer of immunoglobulins to the Calf; Vet Manual Vol. 33 1993—pp. 53-61.
F. B. Garry, DVM,MS; R. Adams, MA, DVM; M. B. Cattell,DVM.MS; R.P. Dinsmore, DVM, MS; Comparison of Passive Immunoglobulin Transfer to Dairy Calves Fed Colostrum of Commercially Available Colostral-Supplement Products; Jan. 1, 1996; JAVMA, vol.208, No. 1, pp. 107-110.
Franklyn Garry, DVM, MS; Brain Aldridge, BVSc and Ragan Adams, MA, DVM; Role of Colostral Transfer in Neonatal Calf Management: Current Concepts in Diagnosis; Aug. 1993; vol. 15, No. 8, pp.1167-1175; Coloradao State University.
D. G. White, MA, VetMB, PhD, MRCVS; Colostral Supplementation in Ruminants; Feb. 1993; vol. 15, No. 2, pp. 335-342; The Royal Veterinary College University of London.
S. F. Abel Francisco, MS, and J. D. Quigley III, Phd; Serum Immunoglobulin Concentrations After Feeding Maternal Colostrum of Maternal Colostrum Plus Colostral Supplement to Diary Calves; Jul. 1993; Am J Vet Res, vol. 54, No. 7, pp. 1051-1054; University of Tennessee.
Gerald H. Stott; Immunoglobulin Absorption in Calf neonates with Special Considerations of Stress; 1980; pp. 681-688; University of Arizona, Tucson.
D. P. Olson, C. J. Papasian and R. C. Ritter; The Effects of Cold Stress on Neonatal Calves; Jan. 1980; pp. 19-23; University of Idaho.
Thomas E. Besser, DVM, Phd; Clive C. Gay, DVM, MVSc; and Lori Pritchett, BS; Comparison of Three Methods of Feeding Colosturm to Dairy Calves; Feb. 1, 1991; JAVMA, vol. 198, No. 3, pp. 419422; Washington State University, Pullman, Washington.
D. G. White and A. H. Andrews; Adequate Concentration of Circulating Colostral Proteins for Market Calves; Aug. 2, 1986; pp. 112-114; Royal Veterinary College.
Sheikh A. Selim, DVM, Msc, MPVm, et al.; Serum Immunoglobulins in Calves: Their Effects and Two Easy, Reliable Means of Measurement; Apr. 1

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