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- Holm, Patrik, 1975-
(författare)
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Functional mapping and in vivo metabolism of the monoclonal antibody TS1 and its single-chain fragment : Its interaction with the antigen and the anti-idiotype
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Antibodies are proteins capable of specific interactions to a wide range of molecules. These interactions are facilitated by the complementary determining regions (CDR).Carcinomas are the most common of human cancers and they release significant amount of cytokeratins (CK) in the necrotic areas of the tumors. The CKs stay in the tumor, since they have low solubility. The antibody studied in this thesis, the anti-CK 8 antibody TS1, has shown to be effective in tumor targeting and is proposed to be useful in therapy.Single-chain antibodies (scFv) are recombinant antibodies which are much smaller than the intact IgG. This is an advantage when used in tumor therapy, since they can penetrate the tumors more easily than the larger IgG. Moreover, they are expressed by one single gene which make them easy to modify, for example by site-directed mutagenesis.The anti-idiotypic antibody αTS1 can be used to clear the TS1 form the circulation and thereby clear the body from non-tumor bound TS1 in therapy. To be able to modify the binding of an antibody to its antigen and or anti-idiotype, these interactions must be studied. In this study this is accomplished by chemical modifications of the IgGs TS1 and αTS1 and the antigen CK 8. Guided by these results, amino acid residues were mutated by using site-directed mutagenesis in the TS1-218 scFv and the effects were studied. From mutational study results, the functional epitope could be mapped and it was found that there are mainly tyrosines, but also charged residues, serine and a tryptophan that are important for both interactions. The binding of TS1-218 to both αTS1 and CK 8 could be improved by changing the negatively charged side-chains by mutations to their corresponding amide or alanine.Both the IgG and scFv versions of TS1 were administered in vivo. The IgG αTS1 was used to clear the TS1 from the circulation by forming immune complexes. The immune complexes, consisting of four or more antibodies, were mainly metabolized by the liver. The scFv TS1-218 could localize to the tumor in a tumor xenograft mouse model, although a higher uptake would be desired in a therapeutic strategy. The scFv was cleared rapidly by the kidneys, but the clearance could be slowed by pre-formed immune complexes with anti-TS1 scFv in vitro, prior to administration in vivo.
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| 2. |
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| 3. |
- Holm, Patrik
(författare)
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Single-chain antibody construction and functional mapping of the monoclonal antibody TS1 : Its interaction with the antigen and the anti-idiotype
- 2005
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aims of this study are to synthesize and produce a single-chain antibody (scFv) of the anti-cytokeratin 8 monoclonal IgG antibody TS1 and to functionally map amino acid residues important for the interaction with its antigen and the anti-idiotypic antibody TS1. The TS1 antibody has been shown to be effective in binding cytokeratin 8 (CK8) expressed in tumors in vivo and is proposed to be useful in immunotargeting and/or immunotherapy. The anti-idiotypic antibody TS1 can be used to regulate the tumor:non-tumor ratio. Mutagenesis of certain amino acid residues can be used to alter the affinity to improve the tumor:non-tumor ratio further. In the present study, the TS1 IgG was chemically modified to specify groups of residues important for interaction with both CK8 and TS1. If important residues were found in the CDRs, they were mutated in the TS1 scFv construct and the effect was studied using ELISA. The main conclusions drawn from this study are that the important amino acid residues in TS1 for the interaction with both CK8 and TS1 are mainly tyrosines, charged residues and a tryptophan. A central interacting interface was identified with the somewhat unusual participation of residues in the CDR 2 of the light chain. Mutations which resulted in increased affinity to both CK8 and TS1 were also identified.
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| 4. |
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| 5. |
- Quiding-Järbrink, Marianne, 1964, et al.
(författare)
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Decreased IgA antibody production in the stomach of gastric adenocarcinoma patients.
- 2009
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Ingår i: Clinical immunology. - : Elsevier BV. - 1521-7035 .- 1521-6616. ; 131:3, s. 463-71
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Tidskriftsartikel (refereegranskat)abstract
- Gastric adenocarcinoma is closely associated with Helicobacter pylori infection. It is also much more frequent in patients with common variable immunodeficiency or selective IgA-deficiency than in the general population. To investigate a possible link between local antibody production and gastric tumors, we studied gastric B cell infiltration and local IgA production in patients with H. pylori induced gastric adenocarcinomas. These studies showed that total and H. pylori-specific IgA antibody levels were substantially lower in gastric tissue from the cancer patients compared to those from asymptomatic H. pylori carriers. However, serum IgA levels were similar in the cancer patients and asymptomatic carriers. As could be expected, H. pylori infected asymptomatic carriers had considerably increased IgA antibody levels compared to uninfected subjects. We conclude that patients suffering from gastric adenocarcinoma have a dramatically decreased local IgA production in the stomach compared to asymptomatic H. pylori infected individuals.
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| 6. |
- Silventoinen, Karri, et al.
(författare)
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Does obesity modify the effect of blood pressure on the risk of cardiovascular disease? : A population-based cohort study of more than one million Swedish men
- 2008
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Ingår i: Circulation. - 0009-7322 .- 1524-4539. ; 118:16, s. 1637-42
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Some studies have suggested that increased blood pressure has a stronger effect on the risk of cardiovascular disease (CVD) in lean persons than in obese persons, although this is not a universal finding. Given the inconsistency of this result, we tested it using a large population-based cohort data set. METHODS AND RESULTS: Systolic and diastolic blood pressures (BPs) and body mass index were measured in 1 145 758 Swedish men born between 1951 and 1976 who were in young adulthood (median age 18.2 years). During the register-based follow-up, which lasted until the end of 2006, 65 611 new CVD events took place, including 6799 myocardial infarctions and 8827 strokes. Hazard ratios (HRs) per 1-SD increase in systolic and diastolic BP were computed within established body mass index categories (underweight, normal, overweight, or obese) with Cox proportional hazards models. The strongest associations of diastolic BP with CVD (HR 1.18), myocardial infarction (HR 1.22), and stroke (HR 1.13) were observed in the obese category. For systolic BP, the strongest associations were observed in the obese category with CVD (HR 1.16) and stroke (HR 1.29) but in the overweight category with myocardial infarction (HR 1.19). We observed statistically significant interactions (P<0.0001) with body mass index for diastolic BP in relation to CVD and for systolic BP in relation to CVD and stroke. CONCLUSIONS: In contrast to the findings of previous studies, we observed a general increase in the magnitude of the association between blood pressure and subsequent CVD with increasing body mass index. Hypertension should not be regarded as a less serious risk factor in obese than in lean or normal-weight persons.
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| 8. |
- Sundström, Patrik, et al.
(författare)
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Human IgA-secreting cells induced by intestinal, but not systemic, immunization respond to CCL25 (TECK) and CCL28 (MEC).
- 2008
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Ingår i: European journal of immunology. - : Wiley. - 0014-2980. ; 38:12, s. 3327-38
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Tidskriftsartikel (refereegranskat)abstract
- Organ-specific homing of lymphoid cells depends on the expression of tissue-specific adhesion molecules and production of specific chemokines. CCL25 (TECK) and CCL28 (MEC) have been reported to direct circulating memory/effector B cells to mucosal tissues. Here, we examined if differential responsiveness to mucosal and systemic chemokines could explain the differential migration pattern of circulating human antibody-secreting cells (ASC), induced by mucosal and systemic immunization. There was a robust migration of specific IgA- and IgM-ASC induced by Salmonella vaccination toward the mucosal chemokines CCL25 and CCL28. In contrast, tetanus-specific ASC migrated to the systemic chemokine CXCL12 (SDF-1alpha) and showed no response to CCL25 or CCL28, not even tetanus-specific IgA-ASC. Cell sorting experiments demonstrated that Salmonella-specific ASC co-expressed CCR9 and CCR10. Our results show that induction site, rather than isotype commitment, determines the chemokine responsiveness and migration pattern of human effector B cells.
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