Development and validation of a nephelometric immunoassay for IgG1 in milk.
A nephelometric immunoassay, with a detection range of 0.3 to 5 g IgG1/l, was (leveloped for the determination of immunoglobulin in bovine milk. The assay exhibited no significant cross-reactivity with alphas1-casein, alphas2-casein, beta-casein, K-casein or beta-lactoglobulin and 39% cross-reactivity with IgG2. The nephelometric assay was compared with ELISA and RID (24 h and 48 h incubations) assays using 105 duplicate milk samples covering IgG1 values ranging from 0.45 to 1.8 g. The results obtained from all assays showed good agreement with the exception of those obtained by the RID assay (24 h incubation) which gave lower results in samples containing more than 1.2 g IgG1/l. It was concluded that the nephelometric assay is a reliable, rapid and convenient method suitable for the quantification of IgG1 in milk. The assay can be configured for routine high-throughput milk quality assurance for IgG1 in dairy laboratories.
Collin
Roger
R
AgResearch, Ruakura Agricultural Centre, Hamilton, New Zealand. roger.collin@agresearch.co.nz
McLaren
Rob
R
Thomson
Mary
M
Malcolm
David
D
D000818:Animals; D002417:Cattle; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000662:veterinary; D007118:Immunoassay / Q000379:methods / Q000662:veterinary*; D007074:Immunoglobulin G / Q000032:analysis* / Q000276:immunology / Q000302:isolation & purification; D008892:Milk / Q000276:immunology*; D008894:Milk Proteins; D009391:Nephelometry and Turbidimetry / Q000379:methods / Q000662:veterinary*; D012680:Sensitivity and Specificity
D007074:Immunoglobulin G; D008894:Milk Proteins