Antibody response in laying hens with small amounts of antigen

Chicken antibodies offer many advantages over the traditional mammalian ones. A laying hen produces large amounts of yolk antibodies and the use of yolk antibodies eliminates the painful procedure of collecting blood from the animal. Thus, the use of chicken antibodies will reduce both the number of animals required to produce antibodies and also animal distress. Chicken antibodies also have several biochemical advantages compared to mammalian antibodies: they often increase the signal and reduce interference in many assays. However, the species chosen for antibody production have usually been mammals. This is probably due to tradition, but also to limited knowledge about the production of chicken antibodies. We studied the immune response in the chicken using small amounts of mammalian antigen, and show that a good immune response can be obtained with 0.1–1.0 μg of bovine serum albumin.     

The effect of surface sugars on liposomes in immunopotentiation

The effect of surface sugars of liposomes on the immunological responses to entrapped antigen has been investigated. alpha-Mannose and beta-galactose were grafted on the surface of liposomes containing lysozyme by covalent coupling of p-aminophenyl-D-glycosides to phosphatidyl ethanolamine liposomes using glutaraldehyde. Subcutaneous administration of antigen entrapped in beta-galactose liposomes stimulated an antibody response comparable to that elicited by sugar-free neutral liposomes. However, alpha-mannose bearing liposomes with entrapped lysozyme elicited an immune response similar to that induced by lysozyme in saline. Based on these observations it is suggested that alpha-mannose liposomes, that are specifically recognized by macrophages, are taken up rapidly by receptor mediated endocytosis and that the entrapped antigen is then rapidly degraded, resulting in low antibody production.     

A possible role for lysozyme in determining acute exacerbation in chronic bronchitis.

The aggregation of non-serotypable Haemophilus influenzae (NTHI) by whole saliva from patients with chronic obstructive lung disease (COLD) was investigated. Significant differences were observed between salivary aggregating activity of a control and COLD population (P < 0.001). Saliva from patients less prone to acute exacerbations had a greater capacity to aggregate bacteria compared with saliva from patients with a predilection to infection. The mechanism of saliva-mediated aggregation of NTHI was investigated and shown to be related to lysozyme content. Lysozyme activity in saliva was measured by the turbidimetric technique and results showed that patients with chronic bronchitis had increased levels of salivary lysozyme, with a subpopulation within the non-infection-prone group having greater amounts. A significant difference was observed in salivary lysozyme between controls and non-infection-prone (P < 0.005) and infection-prone (P < 0.05) patients, respectively: the non-infection-prone patients having significantly (P < 0.005) more than the infection-prone patients. There was significant correlation (r = 0.742, P < 0.001) between salivary aggregation of NTHI and lysozyme activity. Chromatographically purified human lysozyme had a similar aggregation profile to that of saliva. There was no difference in serum and saliva lactoferrin concentrations between groups, but there was a significant increase (P < 0.05) in serum lysozyme concentration in the non-infection-prone group. This study suggests that the level of salivary lysozyme derived from macrophages may play an important role in determining resistance or susceptibility to acute bronchitis.     

An enzymatic cow immunity-targeted approach to reducing milk somatic cell count: 3. A comparative field trial

The effectiveness of lysosubtilin and lysozyme, a combination thereof and a combination of these enzyme preparations (each alone and in combination) with vitamins as possible coimmunostimulants, which reduced the milk somatic cell count (SCC), were compared in a field trial. Seventy second to third lactation Lithuanian Black and White cows with a similar milk SCC ([750±200]×10³?cells?ml^?1) and of a similar weight (550±50?kg) were involved in the trial and were randomly allocated into seven groups (n=10). Lysosubtilin and/or lysozyme at doses of 0.02?g?kg?wt^?1 and 0.2?g?kg?wt^?1, respectively, and vitamins A, C and E (if any) at doses twice as high as required for nutritional adequacy were given, except for control group cows, once daily with feed for ten successive days. After four-, seven-, and ten-day periods of giving enzymes (with or without vitamins) a significant reduction of SCC (p<0.001) was observed in the milk of cows that received a combination of lysozyme with vitamins. On the tenth day a significant reduction of SCC (p<0.001) was also observed in the milk of cows that received lysozyme and lysosubtilin (each alone; without vitamins) or lysosubtilin in combination with vitamins. At the end of the trial (on the 15th day) SCC in milk of cows of all of the study groups was significantly lower (p<0.001) when compared with that of the control group.     

Egg-sharing in assisted conception: ethical and practical considerations

The present acute shortage of eggs for donation cannot be overcomeunless adequate guidelines are set to alleviate the anxietiesregarding payments, in cash or kind, to donors. The currentHuman Fertilisation and Embryology Authority (HFEA) guidelinesdo not allow direct payment to donors but accept the provisionof lower cost or free in-vitro fertilization (IVF) treatmentto women in recognition of oocyte donation to anonymous recipients.Egg-sharing achieved in this way enables two infertile couplesto benefit from a single surgical procedure. However, the practicalguidelines related to this approach are ill-defined at the presenttime leading to some justifiable uncertainty. A pilot studywas therefore undertaken in order to establish the place ofegg-sharing in an assisted conception programme. The currentHFEA guidelines on medical screening of patients, counselling,age and rigid anonymity between the donor and recipient werefollowed. The study involved 55 women (25 donors and 30 recipients)in 73 treatment cycles involving fresh and frozen-thawed embryos.Donors were previous IVF patients who, regardless of their abilityto pay, shared their eggs equally with matched anonymous recipients.They paid only for their consultations and tests right up tothe point of being matched with a recipient The sole recipientpaid the cost applicable in egg donation of a single egg collection,although both received embryo transfers. The results indicatethat although the recipients were older than the donors (41.4± 0.9 versus 31.6 ± 0.5 years), and there wasno difference in the mean number of eggs allocated, the percentagefertilization rates, or the mean number of embryos transferred,there were more births per patient amongst recipients than amongstdonors (30 versus 20%). We conclude that providing the donorsare selected carefully, this scheme whereby a sub-fertile donorhelps a sub-fertile recipient is a very constructive way ofsolving the problem of the shortage of eggs for donation. Thereare also the advantages of including a group of women who wouldotherwise be denied treatment Problems related to ‘patientcoercion’ can, in our view, be fully overcome by the applicationof strict common-sense safeguards. The ideal of pure altruismis not without its medical and moral risk. The success of egg-sharingdepends on shared interests and a degree of altruism betweenthe donor, the recipient and the centre. The current HFEA guidelinesshould be applauded for enabling a highly effective conceptof mutual help to develop.     

Stochastic and Coherence Resonance in an In Silico Neural Model

We show that it is possible for chaotic systems to display the main features of stochastic and coherence resonance. In particular, a model of coupled nonlinear oscillators which emulates the transmembrane voltage activities in CA3 neurons, operating in a chaotic regime and in the presence of noise, can exhibit coherence resonance and stochastic resonance. Certain firing frequencies become more "rhythmic" for some optimal values of noise intensity. The effect of noise in different coupling pathways is investigated. We found that the effect of coherence resonance and stochastic resonance are more prominent if noise is presented in either electric field or gap junction coupling pathways. Frequency sensitivity of the model is investigated as a preliminary step in illustrating the principles of possible epileptic seizure control strategies using "chaos control" concepts. Significant effects of stochastic resonance are observed in the 4-8 Hz range. Weaker effects can be found in the 1-4 Hz and 8-10 Hz ranges whereas 0.5 Hz does not exhibit any resonance phenomenon. Our results suggest that: (a) Stochastic resonance could enhance the intrinsic 4-8 Hz rhythms in CA3 neurons more prominently via field coupling pathways. It could also help explain why some reported seizure control strategies using pulse-trains would only be effective at 0.5 Hz. (b) Stochastic resonance-like behavior can occur in the gamma range only if noise is presented via chemical synaptic pathways.     

Comparison of antibody responses to hen's egg and cow's milk proteins in orally sensitized rats and food-allergic patients

BACKGROUND: No adequate enteral sensitization models are available to study food allergy and the allergenicity of food proteins. To further validate an enteral brown Norway (BN) rat sensitization model under development, we studied specific protein recognition to determine whether a comparable pattern of proteins is recognized by the rat immune system and the human immune system. METHODS: The animals were exposed to either ovalbumin as a positive reference control, hen's egg-white-protein extract, or a cow's milk preparation by daily gavage dosing (0.5, 1, 2.5, 5, 10, or 15 mg protein per rat/day) for 9 weeks. No adjuvants were used during the sensitization studies. The specificities of antibodies against hen's egg-white proteins or cow's-milk proteins in sera from orally sensitized rats and food-allergic patients were studied and compared by immunoblotting. RESULTS: The IgG and IgE antibodies to hen's egg-white proteins and cow's-milk proteins present in sera from orally sensitized rats and food-allergic patients showed a comparable pattern of protein recognition. CONCLUSIONS: Upon daily intragastric exposure to food allergens, the specificities of the induced antibody responses in the BN rat resemble those found in food-allergic patients. These studies add further support to the hypothesis that the BN rat may provide a suitable animal model for food allergy research and research on the allergenicity of food proteins.     

Activation and Sorting of Human White Blood Cells

We demonstrate a novel activation behavior of human leucocyte adhesion under physiological flow conditions in a microfabricated silicon array of channels with length scales similar to those of human capillaries. Vital nuclei stains and cell specific, flourochrome labeled antibodies reveal that the equilibrium distribution of stuck cells in the arrays displays a strong dependence on cell type and nuclear morphology, and there is eventual separation of the two cell types in the array. The distortion of the cells is the same as they experience in vivo and the response of the granulocytes is consistent with a model describing adhesion as a function of the distortion of the cell by its environment; in other words, activated adhesion. We propose that this complex non-random behavior is due to a deformation activated change in the cells relevant to observed in vivo behavior.     

Ontogenesis of the secretory immune system and innate defence factors in human parotid glands

Immunoglobulin-producing cells and epithelial expression of secretory component (SC), amylase, lysozyme (Ly) and lactoferrin (Lf) were studied by immunohistochemistry to obtain information about the development of mucosal immunity. Tissue specimens were obtained from 20 fetal and 40 postnatal parotid glands. (1) Fetal specimens. Occasional IgM- and IgA- but no IgD-, IgG- or IgE- producing cells were seen (ratios, IgM:IgA:IgD:IgG:IgE approximately 4:1:0:0:0). The IgAl subclass dominated (median 90%, range 50-95%) and these cells were mostly J-chain-positive (median 97%, range 94-98%). Only few IgA2-producing cells were seen (median 10%, range 5-50%) and they were also mostly J-chain-positive (median 99%, range 98-100%). Amylase, Ly and Lf were most prominent in early fetal life, while only small amounts of SC were present. (2) Postnatal specimens. Secretory component increased markedly along with a growing number of IgA- and IgD-producing cells (IgA:IgM:IgD:IgG:IgE approximately 4:2:1:1:0). The IgAl subclass remained predominant (median 65%, range 50-90%) although the proportion of IgA2-positive cells tended to be raised (median 35%, range 10-50%). Most IgAl (median 97%, range 67-100%) and IgA2 (median 94%, range 75-100%) cells were J-chain-positive. These features probably reflected local activation of the immune system in response to environmental factors. The amount of amylase, Ly and Lf decreased shortly after delivery, perhaps because the cellular stores were emptied by postnatal increase in secretory activity.