Introduction There is sufficient evidence that blood group related Lewis antigens are tumour-associated molecules. The Lewis y and Lewis b antigens are complex carbohydrates that are over-expressed by breast, lung, colon and ovarian cancers. The SC101 mAb is a unique Lewis y/b binding antibody that binds to native and extended Lewis y and Lewis b haptens, displaying no cross reactivity with H type 1, H type 2, Lewis x or normal blood group antigens.

Heme can serve Haemophilus influenzae as a source of both essential porphyrin and iron. In extracellular mammalian body fluids neither free heme nor free iron is available, since they are tightly bound to hemopexin and transferrin, respectively. Since H. influenzae grows in the presence of iron-transferrin and heme-hemopexin and is known to express a saturable receptor for transferrin, we investigated the process by which this pathogen acquired heme from hemopexin for use as an iron source. The ability of human and rabbit hemopexin to donate heme as a source of iron to H. influenzae type b strains was demonstrated by plate bioassays. With a dot enzyme assay with biotinylated hemopexin as ligand, H. influenzae bound heme-hemopexin and apo-hemopexin following growth in iron-restricted, but not in iron-sufficient, medium. Competitive binding studies with heme-hemopexin and apo-hemopexin demonstrated saturability of binding. Neither heme, protoporphyrin IX, hemoglobin, nor transferrin blocked the binding of hemopexin to whole cells, demonstrating the specificity of binding. Treatment of whole H. influenzae cells with trypsin abolished binding. Taken together, these observations suggest that H. influenzae type b expresses an outer membrane protein(s) which acts as a receptor for hemopexin and which is regulated by the availability of iron in the growth medium. In iron-restricted media, H. influenzae 706705 and DL42 did not express the 100-kDa hemopexin-binding protein previously reported (M.S. Hanson, S.E. Pelzel, J. Latimer, U. Muller-Eberhard, and E.J. Hansen, Proc. Natl. Acad. Sci. USA 89:1973-1977, 1992). The putative iron-regulated hemopexin receptor was solubilized from cell envelopes of H. influenzae 706705, DL42, and Eagan with the detergent CHAPS (3-[(3-cholamidopropyl)-dimethyl-ammonio]-1-propanesulfonate) and isolated by affinity chromatography on heme-hemopexin-Sepharose 4B. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the proteins bound to the affinity resin revealed three proteins of 29, 38, and 57 kDa, of which the 57- and 29-kDa proteins bound hemopexin after Western blotting (immunoblotting). A monoclonal antibody to the 57-kDa hemopexin-binding protein of 706705 recognized a 57-kDa protein on Western blots of the cell envelope proteins of 706705, DL42, and Eagan; no reaction was observed with the 100-kDa hemopexin-binding protein of DL42. These data suggest that some H. influenzae strains possess at least two hemopexin receptors, the expression of which is determined by the prevailing growth environment.

Purpose: To produce antitumor monoclonal antibodies (mAbs) targeting glycans as they are aberrantly expressed in tumors and are coaccessory molecules for key survival pathways.Experimental Design: Two mAbs (FG88.2 and FG88.7) recognizing novel tumor-associated Lewis (Le) glycans were produced by immunizations with plasma membrane lipid extracts of the COLO205 cell line.Results: Glycan array analysis showed that both mAbs bound Le The mAbs demonstrated excellent antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC), in addition to direct tumor cell killing via a caspaseindependent mechanism. Scanning electron microscopy revealed antibody-induced pore formation. In addition, the mAbs internalized, colocalized with lysosomes, and delivered saporin that killed cells with subnanomolar potency. In vivo, the mAbs demonstrated potent antitumor efficacy in a metastatic colorectal tumor model, leading to significant long-term survival.Conclusions: The mAbs direct and immune-assisted tumor cell killing, pan-tumor reactivity, and potent in vivo antitumor efficacy indicate their potential as therapeutic agents for the treatment of multiple solid tumors. In addition, internalization of saporin conjugates and associated tumor cell killing suggests their potential as antibody drug carriers.

Tumor glycans constitute attractive targets for therapeutic antibodies. The sialylated glycocalyx plays a prominent role in cancer progression and immune evasion. Here, we describe the characterization of the mAb, FG129, which targets tumor-associated sialylated glycan, and demonstrate its potential for multimodal cancer therapy. FG129, obtained through BALB/c mouse immunizations with liposomes containing membrane glycan extracts from the colorectal cancer cell line LS180, is an mIgG1k that targets sialyl-di-Lewis a-containing glycoproteins. FG129, as well as its chimeric human IgG1 variant, CH129, binds with nanomolar functional affinity to a range of colorectal, pancreatic, and gastric cancer cell lines. FG129 targets 74% (135/182) of pancreatic, 50% (46/92) of gastric, 36% (100/281) of colorectal, 27% (89/327) of ovarian, and 21% (42/201) of non-small cell lung cancers, by IHC. In our pancreatic cancer cohort, high FG129 glyco-epitope expression was significantly associated with poor prognosis (P ¼ 0.004). Crucially, the glyco-epitope displays limited normal tissue distribution, with FG129 binding weakly to a small percentage of cells within gallbladder, ileum, liver, esophagus, pancreas, and thyroid tissues. Owing to glyco-epitope internalization, we validated payload delivery by CH129 through monomethyl auristatin E (MMAE) or maytansinoid (DM1 and DM4) conjugation. All three CH129 drug conjugates killed high-binding colorectal and pancreatic cancer cell lines with (sub)nanomolar potency, coinciding with significant in vivo xenograft tumor control by CH129-vcMMAE. CH129, with its restricted normal tissue distribution, avid tumor binding, and efficient payload delivery, is a promising candidate for the treatment of sialyl-di-Lewis aexpressing solid tumors, as an antibody-drug conjugate or as an alternative cancer immunotherapy modality.

The question addressed here is whether misleading suggestions made to children a year after target events had occurred will alter long-term recall. One group (3-13 years old when injured and treated in a hospital Emergency Room) were given both misleading and accurate reinstating information a year later, and recall of target events assessed both 1 week and another year later (i.e., 2 years post-injury). A control group had recall assessed both 1 and 2 years post-injury. Misleading had little effect on children's recall 1 week later, although a few misled details were reported. However, a year later virtually none of the misleading information was incorporated into long-term recall. Rather, children were more, not less, accurate when recalling details about which they had been misled. Results were attributed to target events having been highly memorable and well rehearsed via previous recalls, and detection of discrepancies between memory and misleading information focusing attention on targeted details.

A novel monoclonal antibody was raised by immunization of mice with colorectal tumor cell lines. The fusion was screened by immunohistochemistry for binding to primary colorectal tumors. Subsequent analysis on primary disaggregated colorectal tumors show that the antibody recognizes a cell surface antigen expressed by the majority of colorectal tumors. Antigen characterization has shown that the antibody recognizes a sialyltetraosylceramide but does not bind to GM1, GD1a, GT1b, or sialyl Lewis X antigens. Binding to a frozen panel of tumor and normal tissue sections revealed that the antigen was also strongly expressed on esophageal, gastric, and endometrial tumors. Its normal tissue distribution was largely restricted to moderate staining of large intestine. Surprisingly, SC104 antibody directly induces tumor cell death without the need for immune effector cells or complement. This may be related in part to its homophilic binding properties that allow cross-linking of antibody and receptors on the cell surface. Caspase activation can be detected following SC104 treatment of colorectal cells, and cotreatment with caspase inhibitors has been shown to inhibit cell death. This suggests that SC104 induces death by a classic apoptotic pathway. Furthermore, SC104 antibody shows additive killing with complement and 5-fluorouracil/leucovorin in vivo, suggesting a new therapeutic approach for this class of antibodies. (Cancer Res 2006; 66(11): 5901-9)

Haemophilus influenzae acquires iron from the iron-transporting glycoprotein transferrin via a receptor-mediated process. This involves two outer-membrane transferrin-binding proteins (Tbps) termed T b p l and Tbp2 which show considerable preference for the human form of transferrin. Since the Tbps are attracting considerable attention as potential vaccine components, we used transferrin affinity chromatography to examine their conservation amongst 28 H. influenzae type b strains belonging to different outer-membrane-protein subtypes as well as six non-typable strains. Whole cells of all type b and nontypable strains examined bound human transferrin; whilst most strains possessed a T b p l of approximately 105 kDa, the molecular mass of Tbp2 varied from 79 to 94 kDa. Antisera raised against affinity-purified native H. influenzae TbpllTbp2 receptor complex cross-reacted on Western blots with the respective Tbps of all the Haemophilus strains examined. When used to probe Neisseria meningitidis Tbps, sera from each of four mice immunized with the Haemophilus TbplR complex recognized the 68 kDa Tbp2 of N. meningitidis strain B16B6 but not the 78 kDa Tbp2 of N. meningitidis strain 70942. Serum from one mouse also reacted weakly with T b p l of strain B16B6. Apart from a weak reaction with the Tbp2 of a serotype 5 strain, this mouse antiserum failed to recognize the Tbps of the porcine pathogen A. pleuropneumoniae. However, a monospecif ic polyclonal antiserum raised against the denatured Tbp2 of Neisseria meningitidis B16B6 recognized the Tbps of all Haemophilus and Actinobacillus strains examined. Since H. influenzae forms part of the natural flora of the upper respiratory tract, human sera were screened for the presence of antibodies to the Tbps. Sera from healthy adults contained antibodies which recognized both T b p l and Tbp2 from H. influenzae but not N. meningitidis. Convalescent sera from meningococcal meningitis patients contained antibodies which, on Western blots, recognized the Tbps2s of both pathogens. These data demonstrate the existence of shared epitopes on the Tbps of H. influenre, N. meningitidis and A. pleuropneumoniae despite their transferrin species specificity.

Key words: tumour vaccines; helper T-cell responses; blastogenesis; anti-idiotypes; peptidesAnti-idiotypic antibodies that recognise paratopes of anti-tumour antibodies act as internal images of the tumour antigen and thus can be used as surrogate antigens. Although the majority of anti-idiotypic antibodies have been used to stimulate antibody responses, they can also stimulate T cells. Unprimed T cells are stimulated by antigen-presenting cells that take up antigen and present it on MHC molecules in combination with costimulatory signals. Uptake of antigen and expression of costimulatory molecules by antigen-presenting cells are therefore vital for T-cell activation. Antigen can be internalised by pincytosis or more actively by receptor-mediated endocytosis, the latter process being 1,000-fold more efficient. 1 Several scavenging receptors have been identified on antigen-presenting cells including the Fc receptor. 2 More recently, it has been shown that receptor-mediated Fc uptake of antigen/antibody complexes results in the priming of both CD4 and CD8 T-cell responses. 3 These results would suggest that anti-idiotypic antibodies may also be internalised by Fc receptormediated endocytosis and may therefore be very effective immunogens. Two anti-idiotypic antibodies, 105AD7 and 708, have been used to study the role of the Fc region in stimulating T-cell responses by anti-idiotypes.105AD7 is a human anti-idiotypic monoclonal antibody (MAb) that was cloned from a cancer patient receiving the anti-tumour antibody 791T/36 for diagnostic imaging. 4 The antigen recognised by the MAb 791T/36 has been identified as CD55, a complement regulatory protein. 5 CD55 is over-expressed by tumours to protect them from complement attack and thus acts as a tumour-associated antigen. 105AD7 mimics CD55 and can stimulate both T-cell and antibody responses that recognise tumour cells expressing CD55. [5][6][7][8] More recently, neoadjuvant colorectal cancer patients receiving 105AD7 therapy showed a 3-fold increase in tumour cell apoptosis that was associated with infiltration of CD56 and CD4 cells expressing the CD25 activation receptor. 9 -11 708 is a mouse anti-idiotypic antibody that recognises the paratope of the anti-CEA antibody NCRC23 and thus mimics CEA. 708 induces antibody responses that recognise CEA and can stimulate lymphocytes from colorectal cancer patients to respond to in vitro challenge with CEA. 12 This anti-idiotype has recently been cloned and sequenced and shows amino acid homology with CEA.Our study shows that the Fc region of antibodies is important in the presentation of T-cell epitopes. Furthermore, anti-idiotypes expressing human Fc regions are superior to mouse anti-idiotypes in stimulating both helper and cytotoxic T-cell responses and as a result has implications for all antibody-based vaccines.