| 1. |
- Melhus, Håkan, et al.
(författare)
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Epitope mapping of a monoclonal antibody that blocks the binding of retinol-binding protein to its receptor
- 1995
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Ingår i: Biochemical and Biophysical Research Communications - BBRC. - : Elsevier BV. - 0006-291X .- 1090-2104. ; 210:1, s. 105-112
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Tidskriftsartikel (refereegranskat)abstract
- To define the receptor binding site of retinol-binding protein (RBP) we have generated monoclonal antibodies (mAbs) to human RBP and examined their ability to interfere with the receptor binding. MAbs to two conserved regions efficiently blocked the binding. No major conformational changes in the protein occurred upon mAb binding, since the mAbs could co-immunoprecipitate the RBP-transthyretin (TTR) complex. One blocking mAb showed reactivity to a synthetic peptide corresponding to one entrance loop of the retinol-binding pocket (amino acid residues 60-70). Thus, our results show that at least one of the entrance loops of the barrel of RBP is located in or close to the receptor binding site. It can also be concluded that the receptor and TTR binding sites involve different regions of RBP.
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| 2. |
- Melhus, Åsa, et al.
(författare)
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Intra- and interstrain differences of virulence among nontypeable Haemophilus influenzae strains
- 1998
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Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - 0903-4641 .- 1600-0463. ; 106:9, s. 858-868
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Tidskriftsartikel (refereegranskat)abstract
- Nontypeable Haemophilus influenzae (NTHi) is sometimes the causative agent of invasive diseases, and it has been suggested that there may be differences in virulence among NTHi strains. Whilst studying clinical isolates of NTHi in a rat model of acute otitis media, intra- and interstrain differences in virulence were observed. Two strains with suddenly reduced capacity to cause middle ear infections and one highly virulent strain with dose requirements comparable only to encapsulated H. influenzae strains were further investigated, together with 15 other H. influenzae strains. The strains were characterized by analyzing the lipopolysaccharide, the outer membrane proteins, the hemagglutinating ability, and the polymerase chain reaction products after amplification of a gene sequence associated with encapsulation. The pathogenic capacity was assessed in two different in vivo models. It was found that the two strains with reduced pathogenic capacity could regain their virulence after animal passage. The LPS analysis and the results from the chicken embryo model suggested that the observed change in virulence might be associated with the lipopolysaccharide. For the non-animal-passaged strain 3655 there were indications that an undefined factor(s) contributed to its relatively potent virulence. As all three strains lacked genes necessary for encapsulation, in no case could any part of the increased virulence be attributed to the expression of small amounts of capsule.
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| 3. |
- Westman, Eva, et al.
(författare)
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Moraxella catarrhalis-induced purulent otitis media in the rat middle ear : Structure, protection, and serum antibodies
- 1999
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Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - 0903-4641 .- 1600-0463. ; 107:8, s. 737-46
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Tidskriftsartikel (refereegranskat)abstract
- To study the effects of viable and heat-killed Moraxella catarrhalis bacteria on the middle ear mucosa and to evaluate the protection after whole-cell immunizations, Sprague-Dawley rats were challenged and rechallenged with four different M. catarrhalis strains. The animals were monitored by clinical observations, bacterial and histological samples from middle ears, and serum IgG levels. Only viable bacteria at a high concentration induced purulent otitis media, which was culture positive in 58% of the cases on day 4. The infection was characterized by a mild acute reaction lasting otomicroscopically about 8 days, together with quantitative and qualitative changes of the goblet cells. Structurally the mucosal effects of the heat-killed bacteria were less pronounced in the early phase compared to the viable bacteria, but similar at the end of the experiment at 6 months. The intrabullar and subcutaneous immunizations evoked an IgG antibody response in all animals, and the protection rate after immunization was 50% or more. The induced protection was not strain-specific. The study showed the rat to be a possible alternative for the study of different aspects of M. catarrhalis otitis media, an infection that is clinically and structurally different from that elicited by Streptococcus pneumoniae and Haemophilus influenzae in the rat.
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