Electrophoretic analysis of changes in beef myofibrillar proteins during the early post-mortem period

Abstract

three changes of PBS, and incubated for 1 h in an appropriate dilution of patients serum in PBS/Tween 20 (1/200 dilution for IgG detection, 1/100 dilution for IgA or IgM detection). After washing, strips were incubated in peroxidase-labelled goat-anti-human IgG, IgA or IgM antibody (Tago) (1/500 dilution in PBS/Tween 20), and substrate added (1 5 mg of 3-amino-9-ethyl carbazole in 4 ml of dimethylsulphoxide, 46 ml of 0.02 M-acetate buffer, pH 5, 100 pl of H202) . Serum from patients, with candida septicaemia (n = lo), candida urinary tract infection (UTI) (n = 32), oral candidiasis (n = 20) and healthy controls (n = 60), was used. The IgG, IgA and IgM antibody responses of patients (adults, children, neonates) were analysed, and a representative profile of each group is shown in Fig. 1. A marked heterogeneity in the antibody response to cytoplasmic antigens in candida-infected individuals was observed. The antibody response of both adults and children with candida septicaemia, or candida UTI, was predominantly of the IgG class, and was directed against a wide range of antigens of molecular masses 93-1 8 kDa. Serum from all patients reacted with a 45 kDa band. However, the response seen in neonates with UTI differed significantly since the antibodies produced were predominantly IgM, and reacted with 21 kDa and 18 kDa bands. This IgM response may represent a primary immunization with candida. The antibody responses of patients with oral candidiasis differ from other groups in that the IgG and IgA antibody levels are often of equal strength. The 45 kDa band is recognized by most patients, but in 60% of patients with oral candidiasis no antibodies were detected. This may reflect a less serious disease state in these individuals. Thirty-eight per cent of controls had IgG antibodies to the 45kDa band, and to other minor bands, while 62% of controls were negative. The level of positivity in controls may reflect cross-reacting antibodies recognizing candida antigens, or may be the result of a previous subclinical infection. These results emphasize the need to identify infection specific antigens for accurate diagnosis of severe candida infections.