Immunoenzyme Western blotting analysis of antibody specificity in Aleutian disease of mink, a parvovirus infection

5,7-Dihydroxyflavone Analogues May Regulate Lipopolysaccharide-Induced Inflammatory Responses by Suppressing IκBα-Linked Akt and ERK5 Phosphorylation in RAW 264.7 Macrophages

We studied the anti-inflammatory activity of twelve 5,7-dihydroxyflavone analogues in lipopolysaccharide- (LPS-) stimulated RAW 264.7 macrophages. We found that chrysin (1) and 4′-methoxytricetin (9) showed relatively significant anti-inflammatory activity and low cytotoxicity. Moreover, 1 and 9 recovered the expression levels of iNOS and COX2, as well as those of the intracellular inflammatory mediators IL-1β and IL-6, which were upregulated by LPS stimulation. In addition, 1 and 9 actively regulated the phosphorylation of IκBα, leading to the activation of NFκB. Phosphorylation of Akt and ERK5 (upstream of NFκB) by LPS stimulation was significantly regulated by 1 and 9, as well as by BIX 02189 and LY 294002, which are phosphorylation inhibitors of ERK5 and Akt, respectively. The results suggest that compounds 1 and 9 may suppress the levels of iNOS and COX2 by regulating phosphorylation of Akt, ERK5, and IκBα and thus NFκB-related signaling pathways, resulting in anti-inflammatory effects in the cells. Because 1 and 9 showed low cytotoxicity and regulated both PGE₂ and NO production caused by inflammatory responses, they may hold promise as natural anti-inflammatory agents.

Laboratory diagnosis of parvovirus B19 infection

The sensitivity and application of the polymerase chain reaction (PCR) for the diagnosis of parvovirus B19 (B19) infection was investigated by simultaneously assaying a collection of 279 consecutively received samples for presence of anti-B19 IgM and IgG antibodies by Western blot and for B19 DNA by PCR and dot-blot hybridization (dot-blot); samples were sera from patients with suspected B19 infection. PCR and dot-blot detected B19 DNA in 9% (16/179) and 1% (2/179), respectively of Ab-positive samples (IgM+/IgG-, IgM+IgG+, IgM-IgG+), and in 28% (15/54) and 2% (1/54), respectively, of IgM+ samples. PCR also detected B19 DNA in 2% (2/100) of IgM-/IgG- samples, both of which had normal total IgG and IgM levels. PCR is of unique value because it permits diagnosis of B19 infection even in the absence of specific acute phase (IgM) and in the presence or absence of convalescent-phase (IgG) Ab.

Detection of parvovirus B19 by dot-blot and polymerase chain reaction

Our studies compare detection of parvovirus B19 DNA by dot-blot hybridization and by the polymerase chain reaction (PCR). Compared to detection by dot-blot hybridization with a 32P-oligonucleotide probe, the sensitivity of PCR product detection by ethidium bromide fluorescence is not compromised when the size of the amplification target and number of cycles of amplification are properly selected. Our PCR assay simultaneously amplifies two targets in the B19 genome and yields a sensitivity 10 times greater than 32P-labelled oligonucleotide--dot-blot hybridization (dot-blot). In 126 serum samples from cases of suspected parvovirus B19 infection, viral DNA was detected by PCR in 17% (21/126), whereas dot-blot detected B19 DNA in 0.8% (1/126). Parvovirus B19-specific antibodies were detected in 69% (87/126) of the suspected clinical cases by immunoblot. Nineteen of the antibody-positive specimens were DNA positive of which three were IgM-positive/IgG-negative, 11 IgM-positive/IgG-positive and five IgM-negative/IgG-positive. The only dot-blot DNA positive sample was also PCR-DNA positive but was B19 IgM-negative/IgG-negative. Eighty-six B19 antibody-negative, clinically uninfected controls were also negative for B19 DNA by PCR and by dot-blot. These studies confirm the increased sensitivity of gene amplification by PCR for detection of B19 DNA and demonstrate that two targets in B19 DNA can be amplified simultaneously with resultant increased ease of interpretation. Finally, detection of the two B19-specific products by ethidium bromide fluorescence is documented.

Aleutian disease parvovirus infection of mink and ferrets elicits an antibody response to a second nonstructural viral protein

A second nonstructural protein of the Aleutian disease parvovirus was predicted from nucleotide sequence analysis and a detailed transcription map. Western immunoblotting analysis showed that infected mink and ferrets show an antibody response to this predicted protein.

Restricted viral antibody specificity in many ferrets infected with the ferret Aleutian disease parvovirus. Brief report

The majority of ferrets infected with a ferret strain of Aleutian disease virus (ADV) produce antibody only to a detergent-sensitive common determinant on the two closely related virion proteins. Ferrets with high antibody titers and mink infected with this virus also produce antibody to one or more virion immunogenic determinants unaffected by detergent.

Comparative sensitivity of 125I-protein A and enzyme-conjugated antibodies for detection of immunoblotted proteins

Immunoblotting is a powerful technique for the detection of small amounts of immunologically interesting proteins in unpurified preparations. Iodinated protein A (PA) has been widely used as a second antibody for detection of proteins; however, it does not bind equally well to immunoglobulins from different species nor does it bind to all subclasses of immunoglobulin G (IgG). We compared the sensitivity of [125I]PA with those of both horseradish peroxidase-conjugated second antibodies (HRP) and glucose oxidase-anti-glucose oxidase (GAG) soluble complexes for visualizing bovine serum albumin, human IgG, or human C3 which was either dot blotted or electroblotted to nitrocellulose. [125I]PA was uniformly 10- to 100-fold less sensitive than either HRP or GAG. GAG was more sensitive than HRP except for C3 (electroblotting) and bovine serum albumin and IgG (dot blotting), in which they were equivalent. In general, dot blotting was 10- to 1,000-fold more sensitive than electroblotting. Although relative sensitivities varied depending on the proteins analyzed and the antisera used, GAG appeared to be superior to [125I]PA and HRP for detection of immunoblotted proteins.