The polymeric stability of the Escherichia coli F4 (K88) fimbriae enhances its mucosal immunogenicity following oral immunization

&lt;p&gt;Only a few vaccines are commercially available against intestinal infections since the induction of a protective intestinal immune response is difficult to achieve. For instance, oral administration of most proteins results in oral tolerance instead of an antigen-specific immune response. We have shown before that as a result of oral immunization of piglets with F4 fimbriae purified from pathogenic enterotoxigenic Escherichia coli (ETEC), the fimbriae bind to the F4 receptor (F4R) in the intestine and induce a protective F4-specific immune response. F4 fimbriae are very stable polymeric structures composed of some minor subunits and a major subunit FaeG that is also the fimbrial adhesin. In the present study, the mutagenesis experiments identified FaeG amino acids 97 (N to K) and 201 (I to V) as determinants for F4 polymeric stability. The interaction between the FaeG subunits in mutant F4 fimbriae is reduced but both mutant and wild type fimbriae behaved identically in F4R binding and showed equal stability in the gastro-intestinal lumen. Oral immunization experiments indicated that a higher degree of polymerisation of the fimbriae in the intestine was correlated with a better F4-specific mucosal immunogenicity. These data suggest that the mucosal immunogenicity of soluble virulence factors can be increased by the construction of stable polymeric structures and therefore help in the development of effective mucosal vaccines.&lt;/p&gt;</p

R-matrix calculations of low-energy electron alkane collisions

Ab initio electron scattering calculations are presented for methane, ethane and propane with particular emphasis on elastic cross sections. Calculations are performed with the Quantemol-N expert system which runs the UK polyatomic R-matrix code. These calculations are presented which systematically increase the size of the coupled states expansion which is used to represent polarisation effects in the scattering wave function. Agreement with experimental measurements is obtained provided sufficient coupled states are included in the expansion. Whether these coupled states expansions really converge the polarisation potential and the prospects for further calculations are discussed. (c) 2007 Elsevier B.V. All rights reserved

Nutritive potential of some ‘edible’ soils in Blantyre city, Malawi

Background Pregnant women in Malawi consume soil, but the nutritive potential of these soils is uncertain. Methods We collected &lsquo;edible&rsquo; Malawian soil samples from Ndirande, Mpingwe and Soche hills and bought an Indian soil sample from a shop in Limbe and tested them for iron, calcium, zinc, magnesium, lead, pH, Bacillus and Clostridium, using standard methods of analyses. Findings Based on an average daily consumption of fifty grammes of soil, Blantyre &lsquo;edible&rsquo; soils can supply 0.006%, 0.2%, 7% and 74% whilst the Indian soil may supply 0.008%, 0.27%, 8.7%, and 65% of the WHO recommended minimum daily intakes of Magnesium, Calcium, Zinc and iron, respectively. However, both the Blantyre and Indian &lsquo;edible&rsquo; soils also have some traces of lead (0.05 to 0.07 mg/g soil) and spores of Bacillus (4900 &ndash; 13475 colonies/gram) and Clostridium (5050 &ndash; 9050 colonies/gram), which may have undesirable health effects. Blantyre soils were similar but significantly different from the Indian soil which had higher calcium, magnesium, zinc and lead but lower iron. Conclusion The soils have nutritive potential, but they also have harmful aspects. Recommendation Further multidisciplinary research should be conducted to assess the nutritive potential of soils from other areas in Malawi and to examine the health effects of lead and bacterial spores

Thoracic duct fistula and renal transplantation

Thoracic duct drainage (TDD) was established for 21-115 days in 40 kidney recipients with an average removal per patient day of 4.7 1 lymph and 1.88 billion cells. Cellular and humoral immunity were depressed. TDD and immunosuppressive drugs were started at transplantation in 35 recipients of cross-match negative grafts. Although the results were better than in precedent non-TDD controls, eight patients rejected their grafts before a full TDD effect, and three of the eight developed predominantly anti-B lymphocyte cytotoxic antibodies which were probably responsible for positive cross-matches with their next donors. With continuing TDD, all eight patients had good initial function after early retransplantation. In five more 'nontransplantable' patients with performed cytotoxic antibodies, TDD was started 30-56 days before transplantation. In these five pretreated patients, antibodies persisted with positive antidonor cross-matches. Hyperacute rejection occurred repeatedly in two patients with high anti-T (and anti-B) titers, but was surmounted in three patients with lower titers. From the clinical and immunologic data, we have concluded that TDD should be used for pretreatment of all cases with or without prior antibodies, and have suggested an adjustable management plan that takes into account new developments in antibody monitoring