| 1. |
- Sundström, Birgitta, 1953-
(författare)
-
Human cytokeratins : their use as targets in cancer management
- 1990
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Cytokeratins, biochemically related to intermediate filaments (IF), form an intracellular network of filaments which contributes to the mechanical stabilizing of the cell. 19 individual polypeptides, divided into two groups, constitute the cytokeratin family.Each type of epithelial cell can be characterized by its content of cytokeratin polypeptides since the expression pattern varies with the type of epithelium. During the transformation of epithelial cells into tumours, the cytokeratin patterns are usually maintained. This property has enabled cytokeratins to be used as tumour markers, especially for tumours not easily classified.In order to evaluate cytokeratins as tumour markers, we have generated a battery of monoclonal antibodies (MAbs) against cytokeratins extracted from carcinomas. Five antibodies were further characterized. All reacted with cytokeratin 8 (CK 8) amongst others, but only one, TS 1, was specific for this keratin.CK 8 is one of the most abundant keratins in carcinomas. It is released into necrotic areas and can be found intratumourally and in the blood, circulating as partially degraded complexes and can as such be used as a tumour marker. The deposits of cytokeratins in tumours enable these structures to be used as targets for the management of tumours, i.e. by radioimmunodetection and radioimmunotherapy.To assess the value of circulating CK 8 as a serological tumour marker, an enzyme-linked immunosorbent assay (ELISA) was developed, employing two MAbs reactive with different epitopes on CK 8, i.e. TS 3 and TS 4. Serological determinations of CK 8 in cancer of the colon, pancreas and ovary showed that such measurements may be of value for the management of these types of cancer.For in vivo studies of cytokeratins as tumour markers, a nude mouse model carrying HeLa cell tumours was used to evaluate whether cytokeratins can play a role in radioimmunodetection and radioimmunotherapy. In such experiments, TS 1 demonstrated its usefulness in both techniques. The accumulation in the tumour was visualized by conjugated radionuclides and the biological half-life for the antibody was estimated to over 600 h which makes this MAb a suitable reagent for immunotherapy.Immunotherapy experiments in the same animal model showed that a modified approach should be considered if cytokeratins are to be used as the targets. Since antibodies accumulate mainly in necrotic areas, beta-emitters can not be used as in other studies on potential therapy methods. Instead, 125-1 which emits Auger electrons and has a relatively low energy gamma-radiation was investigated. Tumour growth was retarded with both 131-1- and 125-1- conjugated MAbs studied.This thesis indicates that simple epithelial cytokeratins (CK 7, 8, 18, 19) may be useful targets both for radioimmunodetection and radioimmuno-therapy of cancer.
|
|
| 2. |
- Jafari, Rozbeh, 1977-, et al.
(författare)
-
Localization of complexed anticytokeratin 8 scFv TS1-218 to HeLa HEp-2 multicellular tumor spheroids and experimental tumors
- 2010
-
Ingår i: Cancer Biotherapy and Radiopharmaceuticals. - : Mary Ann Liebert Inc. - 1084-9785 .- 1557-8852. ; 25:4, s. 455-463
-
Tidskriftsartikel (refereegranskat)abstract
- Recombinant single-chain fragment variable (scFv) antibodies with specificity to tumor antigens can be used to target tumors in vivo. The approach to use administration of complexes of idiotypic-anti-idiotypic scFvs when targeting tumors has not been tested earlier, and from a theoretical point it could contribute to longer in vivo circulation and improved targeting efficiency by dissociation, when in contact with the target antigen. In this study two models to evaluate the targeting efficiency of such complexes were used. HeLa HEp-2 tumor cells were grown as multicellular tumor spheroids (MCTS) and exposed to the antibody constructs in vitro. The behavior in vivo was tested in an in vivo tumor xenograft model. To increase the size of the anticytokeratin 8 scFv, TS1-218, complexes were formed between TS1-218 and its anti-idiotype, alphaTS1 scFv. The functionality of (125)I-labeled TS1-218 alone and in complex was studied in both models. The uptake patterns were similar in both models. The idiotypic TS1-218 was able to localize to the MCTS and xenografted tumors, both alone and in complex with alphaTS1 scFv. TS1-218 in complex, however, demonstrated a significantly higher uptake than the monomeric TS1-218 in both models (p < 0.0005 and p < 0.0089, respectively). When complexes were administered in vivo, a slower clearance and an increased tumor half-life could be observed. The present investigation indicates that administration of targeting antibodies, with initially blocked antigen-binding sites by complex formation with their anti-idiotypes, may improve targeting efficiency.
|
|
| 3. |
- Holm, Patrik
(författare)
-
Single-chain antibody construction and functional mapping of the monoclonal antibody TS1 : Its interaction with the antigen and the anti-idiotype
- 2005
-
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.
|
|
| 4. |
|
|
| 5. |
- Erlandsson, Ann, et al.
(författare)
-
In vivo clearing of idiotypic antibodies with antiidiotypic antibodies and their derivatives
- 2006
-
Ingår i: Molecular Immunology 2006;42:599-604.
-
Tidskriftsartikel (refereegranskat)abstract
- At immunolocalization of experimental tumors, idiotypic monoclonal antibodies, such as TS1 against cytokeratin 8, can be used to carry and deposit in vivo terapeutics in the tumor. These carriers also remain in the circulation and may cause negative side-effects in other tissues.In this report, several derivatives of the antiidiotypic antibody anti-TS1 were produced and tested for their clearing capacity of the idiotypic carrier antibody TS1. Intact monoclonal anri-TS1, scFv of a anti-TS1 and anti-TS1 Fab and Fab'2 fragments were produced by recombinant technology or by cleavage with Ficin. The scFv was tailored by use of the variable domain genes of the light and heavy chain from the hybridoma clone in combination with a (Gly4Ser)3-linker, followed by expression in E. coli. When tested for clearing capacity, the intact divalent antiidiotypic IgG was found to be the most efficient. The divalent Fab'2 and the monovalent Fab fragment also demonstrated significant clearing, but lower than the intact antiidiotypic IgG. The anti-TS1 scFv antibody when injected separately was not found to clear the idiotype, but could do so when preincubated with the idiotype. Rapid excretion and in vivo instability of this lowmolecular weight antibody fragment may be the major reasons. Similar results were obtained when the system was reversed and the 131I-labeled antiidiotype IgG was cleared with the idiotype Fab'2 fragment. It is concluded that both intact antiidiotypic IgG, Fab'2 and Fab fragments are able to clear the idiotypic antibodies. The experimental data support the conclusion that the Fc parts from both the idiotype and the antiidiotype may contribute to this elimination
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
|
|
