Canine Parvovirus Isolates of India and the Relevance of Canine Parvovirus Type-2 Vaccines

A study was conducted to characterise the field isolates of canine parvovirus (CPV) and an in vitro cross neutralisation assay was performed against the vaccinated dog sera. Out of 45 faecal samples processed for virus isolation, 27 samples showed cytopathic effect (CPE) at first passage, which were confirmed positive by CPV variant types specific PCR. The CPV type 2 was not detected in any of the clinical samples. Of these 27 positive samples only 23 samples showed CPE and were further confirmed as CPV by haemagglutination inhibition test, ELISA and immuno-chromatographic strip test. Antigenic typing performed using a panel of monoclonal antibodies revealed that four of the 23 isolates were CPV 2b type and the remaining 19 isolates were typed as CPV 2a. The antigenic typing results obtained using the monoclonal antibodies corroborated the sequencing results reported by our group earlier. The cross neutralization study with polyclonal sera revealed that the sera of original antigenic type CPV 2 can neutralize the antigenic variants 2a and 2b effectively. Thus we conclude that the vaccines containing CPV type 2 virus can be used to immunise the dogs against the prevalent CPV 2a and CPV 2b infection. A live virus challenge study in dogs may further confirm this observation

Anti-B7-1/B7-2 antibody elicits innate-effector responses in macrophages through NF-kB-dependent pathway

Blocking T cell co-stimulatory signals by anti-B7-1/B7-2 mAb is an attractive approach to treat autoimmune diseases. However, anti-B7-1/B7-2 mAb treatment is known to exacerbate autoimmune diseases through mechanisms not fully understood. Tumor necrosis factor alpha (TNF-α) and reactive oxygen species (ROS) also play important roles in determining the clinical outcome of autoimmune diseases. In this study, we demonstrate that the anti-B7-1 and the anti-B7-2 mAbs activate macrophages for higher induction of TNF-α and other effector responses such as bacterial cytotoxicity and production of ROS. Nuclear factor-kappaB (NF-kB) was found to be increased with anti-B7-1/B7-2 mAb treatment. Inhibition of NF-kB activity by over-expression of phosphorylation-defective I-kappaB alpha in anti-B7-1/B7-2 mAb-treated macrophages decreased TNF-α production. These data indicate that anti-B7-1 and anti-B7-2 mAbs can trigger innate-effector responses in macrophages by activating NF-kB-signaling pathway. Our results suggest that the B7 molecules are not only essential for induction of adaptive immune responses but also play roles in activation of innate immune responses

Studies on the mechanism of transovarian transmission of Salmonella enteritidis in laying hens

Food poisoning caused by Salmonella enteritidis following consumption of contaminated shell eggs is a major public health concern. Epidemiological and microbiological investigations indicated that in vivo contamination of the egg occurs in the reproductive tract of the laying hen. The present study was conducted to understand the contamination of yolk prior to ovulation. After oral inoculations of 140 laying hens with S. enteritidis, the organism was isolated from the preovulatory follicles in 16 birds (from follicle membrane alone in 10 birds, from the follicle yolk alone in four birds and from both membrane and yolk in two birds). This suggested that S. enteritidis interacted with cellular component(s) in the follicular wall. Chicken ovarian granulosa cells, a component of the follicular wall, were cultured in vitro and were used to demonstrate three different patterns of S. enteritidis attachment to these cells namely, local, diffuse, and aggregative. In addition, S. enteritidis can invade the granulosa cells in vitro and multiply in the cytoplasm. Preincubation of bacteria with the tetrapeptide arginine-glycine-aspartate-serine, the amino acid sequence known to mediate the interaction of adhesive glycoproteins with cells, inhibited in vitro attachment of bacteria to granulosa cells. Preincubation of granulosa cells with anti-chicken fibronectin serum or a purified 14 kilodalton fimbrial protein inhibited bacterial attachment to granulosa cells in vitro. Laying hens were orally inoculated with two strains of S. enteritidis with different fimbrial proteins (21 kilodalton and 14 kilodalton) and one strain without fimbriae. Decreased cecal colonization and fecal shedding of the organism were observed in hens that were inoculated with the strain that did not express surface fimbriae compared to birds inoculated with other two strains ($P \u3c .05).$ Mean serum antibody titers of birds inoculated with this strain were also lower than titers of hens inoculated with the other two strains. Immunoblot of bacterial outer membrane structures revealed antibodies against major membrane associated proteins, 14 kilodalton fimbriae and lipopolysaccharide. Fimbrial proteins may mediate attachment of S. enteritidis to cecal epithelium and are able to elicit serum antibodies after oral inoculation

Role of xanthurenic acid 8-O-β-D-glucoside, a novel fluorophore that accumulates in the brunescent human eye lens

We have been able to identify a blue fluorophore from the low-molecular weight soluble fraction of human adult nondiabetic brunescent cataract lenses as xanthurenic acid 8-O-β-D-glucoside (XA8OG) (excitation = 338 nm and emission = 440 nm). To determine the role of this fluorophore in the lens, we have examined its photophysical and photodynamic properties. We found XA8OG to have a fluorescence quantum yield (Φ) of 0.22 and a major emission lifetime of 12 ns. We found it to be a UVA-region sensitizer, capable of efficiently generating singlet oxygen species but little of superoxide. We also demonstrated that XA8OG oxidizes proteins when irradiated with UVA light, causing photodynamic covalent chemical damage to proteins. Its accumulation in the aging human lens (and the attendant decrease of its precursor O-β-D-glucoside of 3-hydroxykynurenine) can, thus, add to the oxidative burden on the system. XA8OG, thus, appears to be an endogenous chromophore in the lens, which can act as a cataractogenic agent

Molecular Characterization of Foot-and-Mouth Disease Virus Type C of Indian Origin

Comparison of nucleotide sequences of the partial 1D region of foot-and-mouth disease type C viruses of Indian origin with those of European, South American, and Southeast Asian viruses revealed that the Indian viruses form a distinct genotype. The vaccine strain C IND/51/79 belongs to this genotype and may be a prototype strain of this genotype