A double recombinant herpes virus of turkeys for the protection of chickens against Newcastle, infectious laryngotracheitis and Marek's diseases.

A double recombinant strain of herpes virus of turkeys (HVT) was constructed that contains the fusion (F) gene from Newcastle disease virus (NDV) and the gD plus gI genes from infectious laryngotracheitis virus (ILTV) inserted into a non-essential region of the HVT genome. Expression of the F protein was controlled by a human cytomegalovirus promoter, whereas expression of gD plus gI was driven by an ILTV promoter. The double recombinant vaccine virus (HVT-NDV-ILT) was fully stable genetically and phenotypically following extended passage in cell culture and infection of chickens. Safety of the vaccine virus was confirmed by overdose and backpassage studies in specific-pathogen-free chickens. Chickens vaccinated with a single dose of HVT-NDV-ILT administered by the in ovo route were highly protected from challenge with the velogenic NDV (GB Texas), ILTV (LT 96-3) and Marek's disease virus (GA 5) strains (97%, 94% and 97%, respectively). Similarly, chickens vaccinated with a single dose by subcutaneous (SC) route at 1 day of age were highly protected from challenge with the same three viruses (100%, 100%, and 88%, respectively). The protection level of a single dose given by in ovo or SC route against challenge with a virulent Marek's disease virus strain demonstrates that insertion of multiple genes from two different pathogens within the HVT genome had no adverse effect on the capacity of HVT to protect against Marek's disease. These results demonstrate that HVT-NDV-ILT is a safe and efficacious vaccine for simultaneous control of NDV, ILTV and Marek's diseases.

Effect of recombinant bovine interleukin-1 beta in normal calves and in calves infected with bovine herpesvirus type 1.

Bovine herpesvirus-1 (BHV-1) is an important pathogen of respiratory infections in cattle. Its continuing importance lies in its ability to predispose infected hosts to bacterial infections. In this present study, we determined whether the immunoregulatory effects induced by interleukin-1 (IL-1) could stimulate appropriate host defense mechanisms to influence the course of BHV-1 infection in cattle. We first evaluated the effect of different doses (10-1000 ng/kg) of IL-1 in normal cattle. A single administration of IL-1 was able to induce a dose-dependent increase in polymorphonuclear (PMN) cells as well as monocytes in peripheral blood. The number of CD3+ lymphocytes and gamma/delta T cells in peripheral circulation decreased transiently in a dose-dependent manner. In the disease model, the effect of IL-1 administration (300 ng/kg) 24 h before, at the time of, and 24 h after the BHV-1 challenge was assessed. As a single therapeutic modality, IL-1 did not significantly reduce the establishment or progression of BHV-1-induced disease. Nevertheless, our results demonstrated that the significant modulation of diverse immune parameters did not exacerbate disease. Thus, the use of IL-1 as an adjunct therapy or as a vaccine adjuvant in cattle can be safely considered in situations where BHV-1 infection is likely to occur.

Maternal nutrition and lactation performance: a study in urban Alexandria.

PIP: Prolonged breastfeeding has been reported to protect the child from grossly defective weaning foods used in most developing countries. Even grossly malnourished mothers have been known to produced enough milk to keep their children alive. Hytten and Thompson reported that there is no evidence that maternal nutrition affect lactation. This study investigates the lactation performance of an unselected group of nursing mothers from a poor to moderate socioeconomic background, and determines the possible effects of their nutritional state on their breast milk and their infants. 41 urban mothers of a moderate to poor socioeconomic status (aged 18 to 38 years) and with an average of 4 pregnancies resulting in 3 surviving children comprised the study population. The mothers were divided into malnourished M group (n=17) and clinically apparently healthy H group (n=24). Biochemical assessments were made of the mothers and their infants, and an NSIM (Nutritional State Index of the Mother) and NSII (Nutritional State Index of the Infant) were made. The malnourished state of the mothers of group M was confirmed by dietary histories and biochemical assessments. 9 mothers in the H group had 'low' serum albumin values, and only 5 had a urea nitrogen/creatinine nitrogen ratio of above 30. The data suggest that the women were consuming a diet poor in protein but adequate in calories. Both groups of mothers produced milk of suboptimal but nonetheless acceptable composition, those in group M having lower concentration of protein and calories than those in group H. On the average, group H mothers produced a normal amount of milk, while group M mothers produced 22% less milk. Most of the infants were found to be of suboptimal nutritional status like the mothers. There was a high correlation between the NSII and amount of milk and of proximate constituents. NSIM correlated very highly with NSII. Nutrition of pregnant women should be improved to control infant malnutrition.^ieng

Cytokine profiles following interaction between bovine alveolar macrophages and Pasteurella haemolytica.

Pasteurella haemolytica is a gram negative bacterium frequently isolated from the lungs of calves suffering from a fibrinous pneumonic condition known as shipping fever. To understand the pathogenesis of this disease, we investigated the induction of cytokin gene expression in cultures of bovine alveolar macrophages (BAM) stimulated with heat-killed P. haemolytica. Northern blot analysis of total RNA showed that P. haemolytica induced early, abundant, and consistent synthesis of IL-1, TNF-alpha, and IL-8 mRNA. Cytokine mRNAs were detected within 1 hr post-stimulation with heat-killed P. haemolytica. IL-1 and IL-8 mRNA accumulated to high levels with increase in stimulation time, whereas TNF-alpha mRNA clearly declined by 4 and 8 h post stimulation. IL-1, TNF-alpha, and IL-8 proteins were also secreted into the culture medium of BAM stimulated with heat-killed P. haemolytica. All three proteins were detected at high levels 8 and 12 h post stimulation with P. haemolytica. BAM cells treated with bovine interferon-alpha and then stimulated with P. haemolytica produced higher amounts of IL-1, IL-8 and TNF-alpha proteins compared to BAM stimulated with P. haemolytica alone. These findings demonstrate the powerful and selective induction of cytokine mRNA and protein synthesis in BAM stimulated with heat-killed P. haemolytica and may explain certain aspects of shipping fever pathogenesis.

Molecular cloning and expression of bovine interleukin-8.

Interleukin-8 (IL-8) is a neutrophil and T-lymphocyte chemotactic and activating factor. This cytokine is produced by many cell types including macrophages in response to a variety of microbial and non-microbial agents. In the present study, we determined the nucleotide sequence for bovine IL-8 cDNA. The amino acid sequence encoded by this cDNA shares 76 and 87% homology with the human and swine IL-8 proteins, respectively. Bovine IL-8 cDNA was expressed in Escherichia coli as a beta-galactosidase fusion protein. Western blotting demonstrates that this fusion protein, but not beta-galactosidase cross-reacts with monospecific anti-human IL-8 antiserum. We also studied the induction of IL-8 mRNA synthesis in bovine alveolar macrophages (BAM) stimulated with heat-killed Pasteurella haemolytica. IL-8 mRNA was induced in BAM as early as 1 h and was detectable at high levels 12 h post-stimulation with P. haemolytica. A dose titration of P. haemolytica and E. coli endotoxins showed that a relatively low level of P. haemolytica endotoxin induced high levels of bovine IL-8 mRNA. The significance of these findings in the pathogenesis of bovine pneumonia caused by P. haemolytica is discussed.