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1.
With the widespread use of therapeutic monoclonal antibodies in the treatment of patients with cancer, resistance to these agents has become a major issue. Preclinical models of drug action or resistance have contributed to unravel the main mechanisms of resistance, involving both tumor-associated and host related factors. However our understanding of how a monoclonal antibody destroys cancer cells in a patient and why it one day stops being effective are still far from being complete. This review focuses on the available data on mechanisms of action and resistance to rituximab and includes some additional information for other monoclonal antibodies. Innovative approaches designed to overcome resistance, such as combination immunotherapy, costimulation with cytokines or growth factors are presented.Key words: monoclonal antibodies, resistance, rituximab, cetuximab, trastuzumab 相似文献
2.
Adherent epithelial cancer cells, such as colon cancer cells, are much more resistant to anthracyclines and to many other major anticancer agents when the cell population reaches confluence. Our purpose is to analyze the mechanisms of this confluence dependent resistance (CDR) that is probably the major cause of the natural resistance of solid tumors to chemotherapy. Some drugs (anthracyclines, etoposide and vincristine) but not others (cisplatin, melphalan and 5-fluorouracil) accumulate less in confluent than in nonconfluent cells. A decrease of the passive transmembrane drug transport in confluent cells is associated to a reduced membrane fluidity. However, the predominant mechanism of CDR is an increase in the intrinsic resistance of the DNA to the drug-induced damage. This mechanism is now relatively well understood for anthracyclines and etoposide that act mainly through an inhibition of the topoisomerase II: as the enzyme level is low in slowly proliferating confluent cells, the number of drug-induced DNA strand breaks is lower than in rapidly growing nonconfluent cells which highly express the topoisomerase II gene. Mechanisms of CDR for the other drugs are less clear and could involve an increase in the ability to repair damaged DNA. Attempts to circumvent CDR could consist in the stimulation of the cell proliferation by hormones or growth factors, or in the recruitment of quiescent cells into the S and G2 phases by previous treatment of confluent cells with infratoxic concentration of DNA-damaging agents. 相似文献
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We have developed a novel dual-acting maleimide-bearing prodrug that incorporates the anticancer agent doxorubicin and an inhibitor of the P-glycoprotein efflux pump that is over-expressed in multidrug resistant tumor cells. Additionally, the prodrug contains a 1,6-self-immolative spacer coupled to the dipeptide Phe-Lys that acts as a substrate for cathepsin B. The prodrug, once bound through its maleimide moiety to the cysteine-34 group of human serum albumin, was cleaved by cathepsin B and in tumor homogenates demonstrating a release of the anticancer agent doxorubicin and the inhibitor. 相似文献
4.
Characterization of monoclonal antibodies to bromodeoxyuridine 总被引:7,自引:0,他引:7
The characteristics of three mouse monoclonal antibodies to halogenated uridine derivatives are presented. Two, IU-1 and IU-2, are produced by hybridomas derived in our laboratory, and the third is the B-44 hybridoma described by Gratzner (7) and obtained commercially from Becton-Dickinson Monoclonal Center. Hybridomas IU-1 and IU-2 were derived from the fusion of spleen cells from a Biozzi High Responder mouse immunized with iododeoxyuridine (IdUrd) conjugated to bovine serum albumin and SP2/0 mouse myeloma cells. This paper presents methods and results for enzyme-linked immunosorbent assays (ELISA) against whole cells labeled with bromodeoxyuridine (BrdUrd), ELISA against BrdUrd-labeled DNA, and a competition ELISA for free BrdUrd. All three antibodies show similar binding affinities and specificities. The IU antibodies react with BrdUrd and IdUrd when the nucleosides are either free in solution or incorporated into single-stranded DNA (ss-DNA). The antibodies do not recognize either halogenated base in double-stranded DNA (ds-DNA), nor do they react with uracil or bromocytidine. Weak binding to thymidine, 5-fluorodeoxyuridine, and unsubstituted ss-DNA occurs. 相似文献
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MDR results from overexpression of P-glycoprotein (Pgp) and multidrug resistance protein (MRP or MRP1) that function as ATP-dependent efflux pumps. Lung resistance related protein (LRP) is also supposed to be involved in MDR. The human canalicular multispecific organic anion transporter (cMOAT) gene that is responsible for the defects in Dubin-Johnson syndrome was isolated. cMOAT is homologous to MRP1 and supposed to be involved in drug resistance. Human cMOAT cDNA transfected LLC-PK1 cells, LLC/cMOAT-1, have increased resistance to vincristine (VCR), 7-ethyl-10-hydroxycamptothecin (SN-38), and cisplatin. The multidrug resistance (MDR)-reversing agents, cyclosporin A (CsA) and PAK-104P, almost completely reversed the resistance to VCR, SN-38 and cisplatin of LLC/cMOAT-1 cells by interacting with the substrate binding site of cMOAT. Treatment of human colorectal carcinoma SW-620 cells with sodium butyrate(NaB) induced LRP in the cells and conferred resistance to Adrianycin(ADM), VCR, VP-16, gramicidin D and taxol. Two LRP-specific ribozymes inhibited the NaB-induced expression of LRP in SW-620 cells and almost completely abolished their acquisition of the MDR phenotype. The accumulation of ADM, VCR and taxol was not decreased in NaB-treated cells, suggesting that ATP-binding cassette transporters are not involved in the MDR of NaB-treated cells. ADM was mainly located in the nuclei of untreated and the cytoplasm of NaB-treated cells. The accumulation level of ADM in the nuclei isolated from untreated cells or those from treated cells in the presence of anti-LRP polyclonal antibody was higher than that from treated cells in the absence of the antibody. Efflux of ADM from nuclei isolated from NaB-treated cells was enhanced compared with those from untreated cells and NaB-treated cells transfected with a LRP-specific ribozyme. The polyclonal antibody against LRP inhibited the enhanced efflux of ADM from nuclei isolated from NaB-treated cells. These findings indicate that LRP is involved in resistance to ADM, VCR, VP-16, taxol and gramicidin D, and has an important role in the transport of ADM from the nucleus to the cytoplasm. 相似文献
7.
Monoclonal antibodies were produced to whole cells of heat-treated Escherichia coli. Balb/c mice were immunized with a pool of five strains of heat-treated E. coli , and the resulting hybridomas were screened by indirect immunoassay. E. coli strains other than those used for immunization were used for screening to detect hybridomas producing antibody that reacted with a large number of E. coli strains. Of 864 hybridomas, 32 reacted strongly with either two or all three of the strains used for screening; 15 were successfully cloned. Antibody from hybridoma 6H2 reacted with 35 of 68 (51%) E. coli ; of 13 non- E. coli tested, only Enterobacter agglomerans was weakly positive. Hybridoma 9B12 antibody reacted with all six E. coli tested. Hybridoma 9B12, however, stopped producing antibody. Five hybridomas produced antibody which reacted with a majority of the bacteria tested whereas antibodies from two other hybridomas reacted with several E. coli and non- E. coli. Polyclonal antibodies produced to two strains of E. coli varied in the numbers of E. coli with which they reacted; both antisera cross-reacted with several non- E. coli. 相似文献
8.
Production and specificity of monoclonal antibodies and polyclonal antibodies to Escherichia coli 总被引:3,自引:0,他引:3
Monoclonal antibodies were produced to whole cells of heat-treated Escherichia coli. Balb/c mice were immunized with a pool of five strains of heat-treated E. coli, and the resulting hybridomas were screened by indirect immunoassay. E. coli strains other than those used for immunization were used for screening to detect hybridomas producing antibody that reacted with a large number of E. coli strains. Of 864 hybridomas, 32 reacted strongly with either two or all three of the strains used for screening; 15 were successfully cloned. Antibody from hybridoma 6H2 reacted with 35 of 68 (51%) E. coli; of 13 non-E. coli tested, only Enterobacter agglomerans was weakly positive. Hybridoma 9B12 antibody reacted with all six E. coli tested. Hybridoma 9B12, however, stopped producing antibody. Five hybridomas produced antibody which reacted with a majority of the bacteria tested whereas antibodies from two other hybridomas reacted with several E. coli and non-E. coli. Polyclonal antibodies produced to two strains of E. coli varied in the numbers of E. coli with which they reacted; both antisera cross-reacted with several non-E. coli. 相似文献
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C G Frondoza S Logan G Forloni J T Coyle 《The journal of histochemistry and cytochemistry》1990,38(4):493-502
N-acetyl-aspartyl-glutamate (NAAG) is a putative neuromodulator/neurotransmitter in the mammalian nervous system. Immunohistochemical studies with polyclonal NAAG antisera have revealed immunoreactive neurons and processes in several brain regions. However, these antisera crossreact to some degree with N-acetyl-aspartate (NAA), which is present in mM concentrations in brain, prompting the development of monoclonal antibodies (MAb) more specific for NAAG. By fusing spleen lymphocytes obtained from BALB/c mice pre-immunized with NAAG covalently linked to bovine serum albumin by carbodiimide with SP2/0-Ag 14 mouse myeloma cells, we produced three IgG2a (kappa) MAb which specifically reacted with NAAG. These MAb exhibited negligible crossreactivity with NAA or with structurally similar peptides, as shown by solid-phase radioimmunoassay. Antibody activity was absorbed out selectively by both NAAG-thyroglobulin conjugate and free NAAG. These MAb stained many nuclei of the medulla-pons and midbrain, mitral cells in the olfactory bulb, pyramidal neurons in sensorimotor cortex, locus ceruleus, and several cholinergic cranial nuclei. The staining pattern strongly correlated with NAAG levels determined by HPLC. Monoclonal antibodies significantly enhanced sensitivity of staining, allowing visualization of dorsal horn neurons in spinal cord, which were not readily detectable with polyclonal antiserum. Availability of these MAb now facilitates further clarification of the role of NAAG in the brain. 相似文献
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Two monoclonal antibodies (ADM-1-11 and 79-31 mAbs) were raised against daunomycin (DM) conjugated to bovine serum albumin
via the cross-linker N-(gamma-maleimidobutyryloxy)succinimide. The monoclonal antibodies (mAbs) specifically detected DM as well as its analogs
doxorubicin and epirubicin, but did not react with other anticancer antibiotics, including pepleomycin, mitomycin C, and actinomycin
D. The mAbs reacted strongly with glutaraldehyde-conjugated DM in an enzyme linked immunosorbent assay (ELISA) used as a model
system for immunocytochemistry as well as in appropriately pretreated sections of tissues from animals injected with DM. No
staining occurred in tissues from uninjected animals. In order to perform DM ICC a number of tissue treatment conditions critical
to the detection of low molecular weight substances were employed. Uptake of DM was studied in rats after a single i.v. or
i.p. administration of the drug. In the heart, accumulation of DM occurred in nuclei and in the cytoplasm. In the kidney,
DM immunoreactivity accumulated in all segments of the nephron except for the proximal tubules. Since the proximal tubules
are known to be where a variety of transport systems including P-glycoprotein (Pgp) and organic anion-transporting polypeptides
(OATPs) in drug interactions occur, the absence of DM accumulation in these segments may reflect a transport phenomenon depending
upon such transporters. The availability of methods to study sites of accumulation of DM offers possibilities for understanding
toxic side effects of this drug on the heart and kidney. Moreover, the immunocytochemical methodology developed may prove
useful for the localization of other low molecular weight drugs that can be fixed in situ by glutaraldehyde. 相似文献
12.
Rabbit polyclonal antibodies to the idiotype of murine monoclonal anti-sperm antibodies were developed and characterized. M29.6 and M42.15 are monoclonal antibodies (mAbs) that inhibit fertilization in vivo and in vitro. Sera from rabbits inoculated with purified mAbs (Ab1) were absorbed with normal mouse and isotype-specific immunoglobulin (Ig); the anti-idiotype Ig fraction (Ab2) was isolated by protein A-chromatography or by chromatography on the corresponding idiotype column. Binding specificity of Ab2 was confirmed by measuring the reactivity of Ab2 with homologous and heterologous mAbs. Ab2 competitively inhibited 125I-labeled Ab1 binding to mouse sperm, suggesting that the Ab2 preparation possessed subpopulations directed against idiotopes similar or adjacent to the antigen-binding site of the mAb. Anti-idiotype antibodies reactive with the antigen-combining site of the anti-sperm mAb may contain subpopulations that mimic the mouse sperm epitope recognized by Ab1. Immunization with Ab2 induced anti-(anti-idiotype) antibodies (Ab3), which competitively inhibited binding of 125I-labeled Ab1 to immobilized Ab2. These results are consistent with the hypothesis that immunization of mice with antibodies to the idiotype of sperm-specific mAbs can induce antibodies that share structural similarities with the anti-sperm mAb used for their induction. Immunization with anti-idiotype antibodies that mimic sperm antigen structure represents a possible strategy for induction of immunity to sperm. 相似文献
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Twelve syngeneic anti-idiotopic mAb (anti-idiotypic/idiotopic antibodies Ab2)) were prepared from CBH/Cbi rats immunized with one of three monoclonal anti-HSN antibodies (Ab1) (11/160, ALN/11/53, or ALN/16/53) specific for the HSN tumor. The sera of the rats used for hybridoma production and all of the monoclonal Ab2 specifically inhibited the binding to HSN of the immunizing Ab1 only. It is concluded that, in this completely syngeneic system, only the private idiotopes associated with the antibody-combining site were immunogenic. Analyses using Western blotting showed that the Ab2 bound to intact Ab1 and to isolated H chains where the intra-strand disulfide bonds remained intact. The Ab2 did not bind to L chains or to fully reduced H chains of the Ab1. It is concluded that the idiotopes expressed on the H chain were conformational. When a panel of 13 monoclonal Ab1 (including the three used for immunization) were tested for reactivity with the Ab2, three reacted specifically with their respective Ab2 and 8 gave no binding suggesting that each Ab1 had a distinct idiotypic specificity despite the fact that all the Ab1 competed with each other for binding to Ag. However, the two remaining Ab1 (ALN/9/94 and ALN/12/17) generated from different tumor-bearing rats, were found to possess the same idiotypic specificity as 11/160. A detailed analysis using seven Ab2 raised against 11/160 showed that while the idiotype of ALN/9/94 and 11/160 were very similar, that of ALN/12/17 showed some clear differences. These three Ab1 have been shown previously to bind a sequential epitope on the HSN Ag in Western blots and it is postulated that the common idiotype of these Ab1 reflects their recognition of a sequential epitope. This may also account for the relatively frequent occurrence in tumor bearer sera of antibodies with this Id. 相似文献
14.
Characterization of monoclonal antibodies to Treponema pallidum 总被引:19,自引:0,他引:19
S A Lukehart M R Tam J Hom S A Baker-Zander K K Holmes R C Nowinski 《Journal of immunology (Baltimore, Md. : 1950)》1985,134(1):585-592
Thirteen hybrid cell lines which produce mouse monoclonal antibodies to Treponema pallidum, the causative agent of syphilis, have been established. All of the monoclonal antibodies react with T. pallidum, Nichols strain, in ELISA and in immunofluorescence assays, but do not react with normal rabbit testicular tissue in the ELISA. Two of these antibodies were demonstrated to react with the nonpathogenic treponemes T. phagedenis, biotype Reiter, T. refringens (Noguchi strain), T. vincentii, and T. denticola (strains 11 and W), as well as with Borrelia recurrentis, Leptospira interrogans, serogroup Canicola, and the swine pathogen T. hyodysenteriae. The remaining 11 antibodies react with four recently isolated strains of T. pallidum, but with none of the related nonpathogens nor with Borrelia or Leptospira. Thus, our results to date indicate that these monoclonal antibodies may identify antigenic determinants that are specific either for T. pallidum alone or for those treponemes which are pathogenic for humans. The molecular specificities of six of the 13 antibodies were determined by Western blotting. We anticipate potential usefulness of these antibodies in the investigation of the antigenic structure of T. pallidum, the taxonomic study of the pathogenic and nonpathogenic treponemes, and in the diagnosis of syphilis. 相似文献
15.
Two new monoclonal antibodies to 3 beta-hydroxy-gibberellins are described. Monoclonal antibodies GA1-1 and GA1-2 were derived from immunizations with the hapten-protein conjugate gibberellin A1-17-KLH. Cross-reactivities with a panel of 43 gibberellins and gibberellin derivatives are compared with those of other anti-gibberellin monoclonal antibodies. 相似文献
16.
V V Sviridov E V Kozhevnikova 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1985,(9):67-70
The immunization of mice with the protein fraction of B. pertussis strain 305 has made it possible to obtain hybridomas producing monoclonal antibodies to B. pertussis antigens. Ascitic fluids containing monoclonal antibodies react in the ELISA in high titers and actively agglutinate B. pertussis strains 305 and 475. 相似文献
17.
Reaction patterns of monoclonal antibodies to DNA 总被引:9,自引:0,他引:9
R J Smeenk K Brinkman H G van den Brink A A Westgeest 《Journal of immunology (Baltimore, Md. : 1950)》1988,140(11):3786-3792
Starting with spleen cells from MRL/lpr, NZB/W, and graft-vs-host-diseased mice, we prepared a total of 57 hybridomas that produce antibodies to DNA. Using various approaches, we studied the avidity of these monoclonals in relation to their behavior in four anti-DNA assays. From the results obtained, we postulate that on the basis of anti-DNA avidity the anti-DNA ELISA, the polyethylene glycol assay, the indirect immunofluorescence test on Crithidia luciliae, and the Farr assay (in this order) detect a decreasing amount of anti-dsDNA, the Farr assay being strictly selective for high avidity anti-dsDNA. mAb selected by the anti-DNA ELISA generally were of a low avidity toward DNA. Using cardiolipin and dextran sulfate, a polyanion that bears a resemblance in charge to DNA, we studied the cross-reactivity of the monoclonals. A total of 6 of the 57 monoclonals were found to cross-react with cardiolipin, and 26 with dextran sulfate. We observed an inverse relationship between anti-DNA avidity and cross-reactivity: the lower the avidity of the antibody, the more cross-reactive it is. Based on these findings, we postulate that it is at least questionable whether low avidity, cross-reactive (monoclonal) anti-DNA is representative for the anti-DNA found in patients with SLE. 相似文献
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