Nonclinical immunogenicity risk assessment for knobs-into-holes bispecific IgG antibodies.

Bispecific antibodies, including bispecific IgG, are emerging as an important new class of antibody therapeutics. As a result, we, as well as others, have developed engineering strategies designed to facilitate the efficient production of bispecific IgG for clinical development. For example, we have extensively used knobs-into-holes (KIH) mutations to facilitate the heterodimerization of antibody heavy chains and more recently Fab mutations to promote cognate heavy/light chain pairing for efficient assembly of bispecific IgG in single host cells.

Development of a Cell-based Neutralizing Antibody Assay for Zinpentraxin Alfa: Challenges and Mitigation Strategies.

Therapeutic protein drugs can potentially induce immune responses in patients and result in the production of anti-drug antibodies (ADAs), including a subset of ADAs called neutralizing antibodies (NAbs) that might cause loss of efficacy by inhibiting clinical activities of the drug. Herein, we describe the unique challenges encountered during the development of a fit-for-purpose cell-based NAb assay for a new protein modality, zinpentraxin alfa, including our strategies for assay design to overcome various matrix interferences and improve assay drug tolerance. We demonstrated that a typical biotin-drug extraction with acid dissociation (BEAD) approach alone was not sufficient to eliminate matrix interferences in this assay.

Structure Guided Design of Bacteriophage Qβ Mutants as Next Generation Carriers for Conjugate Vaccines.

Vaccines are critical tools to treat and prevent diseases. For an effective conjugate vaccine, the carrier is crucial, but few carriers are available for clinical applications. In addition, a drawback of current protein carriers is that high levels of antibodies against the carrier are induced by the conjugate vaccine, which are known to interfere with the immune responses against the target antigen.

MicroRNA-217 acts as a tumor suppressor and correlates with the chemoresistance of cervical carcinoma to cisplatin.

Background: MicroRNA-217 (miR-217) has been demonstrated to participate in the tumorigenesis and progression of various types of cancers. Nevertheless, the role of miR-217 in cervical carcinoma still remains not fully elucidated. This current work sought to investigate the role of miR-217 in the growth, migration, and invasion of cervical carcinoma and detect the role of miR-217 in the chemosensitivity of cervical carcinoma cell to cisplatin.

Protective Epitope Discovery and Design of MUC1-based Vaccine for Effective Tumor Protections in Immunotolerant Mice.

Human mucin-1 (MUC1) is a highly attractive antigen for the development of anticancer vaccines. However, in human clinical trials of multiple MUC1 based vaccines, despite the generation of anti-MUC1 antibodies, the antibodies often failed to exhibit much binding to tumor presumably due to the challenges in inducing protective immune responses in the immunotolerant environment. To design effective MUC1 based vaccines functioning in immunotolerant hosts, vaccine constructs were first synthesized by covalently linking the powerful bacteriophage Qβ carrier with MUC1 glycopeptides containing 20-22 amino acid residues covering one full length of the tandem repeat region of MUC1.

Antitumor Humoral and T Cell Responses by Mucin-1 Conjugates of Bacteriophage Qβ in Wild-type Mice.

Mucin-1 (MUC1) is one of the top ranked tumor associated antigens. In order to generate effective anti-MUC1 immune responses as potential anticancer vaccines, MUC1 peptides and glycopeptides have been covalently conjugated to bacteriophage Qβ. Immunization of mice with these constructs led to highly potent antibody responses with IgG titers over one million, which are among the highest anti-MUC1 IgG titers reported to date.

Delivery of foreign cytotoxic T lymphocyte epitopes to tumor tissues for effective antitumor immunotherapy against pre-established solid tumors in mice.

Cytotoxic T lymphocyte (CTL) can have remarkable abilities to kill tumor cells. However, the establishment of successful CTL-based anticancer therapy has met with many challenges. Within tumor cells, there exist subpopulations with low or no expression of the targeted antigen (termed as antigen-loss variants).

PD-1 Suppresses Development of Humoral Responses That Protect against Tn-Bearing Tumors.

Tn is a carbohydrate antigen uniquely exposed on tumor mucins and, thus, an ideal target for immunotherapy. However, it has been difficult to elicit protective antibody responses against Tn antigen and other tumor-associated carbohydrate antigens. Our study demonstrates this can be attributed to PD-1 immuno-inhibition.

Valency and density matter: Deciphering impacts of immunogen structures on immune responses against a tumor associated carbohydrate antigen using synthetic glycopolymers.

For successful carbohydrate based anti-cancer vaccines, it is critical that B cells are activated to secret antibodies targeting the tumor associated carbohydrate antigens (TACAs). Despite the availability of many TACA based constructs, systematic understanding of the effects of structural features on anti-glycan antibody responses is lacking. In this study, a series of defined synthetic glyco-polymers bearing a representative TACA, i.

Chemical Synthesis of GM2 Glycans, Bioconjugation with Bacteriophage Qβ, and the Induction of Anticancer Antibodies.

The development of carbohydrate-based antitumor vaccines is an attractive approach towards tumor prevention and treatment. Herein, we focused on the ganglioside GM2 tumor-associated carbohydrate antigen (TACA), which is overexpressed in a wide range of tumor cells. GM2 was synthesized chemically and conjugated with a virus-like particle derived from bacteriophage Qβ.

Significant Impact of Immunogen Design on the Diversity of Antibodies Generated by Carbohydrate-Based Anticancer Vaccine.

Development of an effective vaccine targeting tumor associated carbohydrate antigens (TACAs) is an appealing approach toward tumor immunotherapy. While much emphasis has been typically placed on generating high antibody titers against the immunizing antigen, the impact of immunogen design on the diversity of TACA-specific antibodies elicited has been overlooked. Herein, we report that the immunogen structure can significantly impact the breadth and the magnitude of humoral responses.

Lipopeptide-Coated Iron Oxide Nanoparticles as Potential Glycoconjugate-Based Synthetic Anticancer Vaccines.

Although iron oxide magnetic nanoparticles (NPs) have been widely utilized in molecular imaging and drug delivery studies, they have not been evaluated as carriers for glycoconjugate-based anticancer vaccines. Tumor-associated carbohydrate antigens (TACAs) are attractive targets for the development of anticancer vaccines. Due to the weak immunogenicity of these antigens, it is highly challenging to elicit strong anti-TACA immune responses.

Carbohydrate antigen delivery by water soluble copolymers as potential anti-cancer vaccines.

Tumor associated carbohydrate antigens (TACAs) are overexpressed on tumor cells, which renders them attractive targets for anti-cancer vaccines. To overcome the poor immunogenicity of TACAs, we designed a polymer platform for antigen presentation by co-delivering TACA and helper T (Th) cell epitope on the same chain. The block copolymer was synthesized by cyanoxyl-mediated free radical polymerization followed by conjugation with a TACA Tn antigen and a mouse Th-cell peptide epitope derived from polio virus (PV) to afford the vaccine construct.

A carbohydrate-based approach for the total synthesis of (-)-dinemasone B, (+)-4a-epi-dinemasone B, (-)-7-epi-dinemasone B, and (+)-4a,7-Di-epi-dinemasone B.

(-)-Dinemasone B was isolated by Krohn and co-workers from a culture of the endophytic fungus Dinemasporium strigosum and has shown promising antimicrobial activity. Described herein is the first total synthesis of (-)-dinemasone B, (+)-4a-epi-dinemasone B, (-)-7-epi-dinemasone B, and (+)-4a,7-di-epi-dinemasone B. Their absolute configurations were also determined.

Boosting immunity to small tumor-associated carbohydrates with bacteriophage qβ capsids.

The development of an effective immunotherapy is an attractive strategy toward cancer treatment. Tumor associated carbohydrate antigens (TACAs) are overexpressed on a variety of cancer cell surfaces, which present tempting targets for anticancer vaccine development. However, such carbohydrates are often poorly immunogenic.

Chemical synthesis of a heparan sulfate glycopeptide: syndecan-1.

The highly complex structure of syndecan-1 heparan sulfate glycopeptide was successfully assembled. The protective groups utilized and sequences for glycosyl linkage formation and protective group removal are critical for the success of synthesis. This is the first time this type of sulfated glycopeptides has been prepared, which lays the foundation to access other members of this important class of molecules.

Tobacco mosaic virus as a new carrier for tumor associated carbohydrate antigens.

Tumor-associated carbohydrate antigens (TACAs) are being actively studied as targets for antitumor vaccine development. One serious challenge was the low immunogenecity of these antigens. Herein, we report the results of using the tobacco mosaic virus (TMV) capsid as a promising carrier of a weakly immunogenic TACA, the monomeric Tn antigen.

Recent Development in Carbohydrate Based Anti-cancer Vaccines.

The development of carbohydrate based anti-cancer vaccines is of high current interests. Herein, the latest development in this exciting field is reviewed. After a general introduction about tumor associated carbohydrate antigens and immune responses, the review is focused on the various strategies that have been developed to enhance the immunogenecity of these antigens.

Active cobalt catalyst for the cleavage of benzyl ether.

An improved method for the deprotection of benzyl ethers using a catalytic amount of Co(2)(CO)(8) in the presence of Me(2)PhSiH and CO (1 atm) is described. The deprotection reaction is compatible with double bond or sulfur-containing substrates. The method also tolerates other functional groups, such as Ac, Piv, and Bz, and shows potential selectivity in perbenzylated monosaccharides.

Divergent heparin oligosaccharide synthesis with preinstalled sulfate esters.

Traditional chemical synthesis of heparin oligosaccharides first involves assembly of the full length oligosaccharide backbone followed by sulfation. Herein, we report an alternative strategy in which the O-sulfate was introduced onto glycosyl building blocks as a trichloroethyl ester prior to assembly of the full length oligosaccharide. This allowed divergent preparation of both sulfated and non-sulfated building blocks from common advanced intermediates.

Highly efficient and mild method for regioselective de-O-benzylation of saccharides by Co2(CO)8-Et3SiH-CO reagent system.

A highly efficient and mild method for the de-O-benzylation of protected saccharides was developed by transforming terminal benzyl ethers into silyl ethers using Co(2)(CO)(8)-Et(3)SiH under 1 atm of CO. The method was successfully used for the de-O-benzylation of perbenzylated monosaccharides with various anomeric protecting groups, as well as natural disaccharides and trisaccharides such as sucrose, raffinose, and melezitose in good yields (>80%).

Design and synthesis of novel multivalent mannosides targeting the mannose receptor.

According to the characteristics of C-type lectin-like domains in the mannose receptor (MR), a novel design of multivalent mannosides targeting the MR was accomplished. Beginning with a divalent mannoside as the sugar unit, a series of multivalent mannosides with variations in both valence and space were synthesized in a convergent approach. The synthetic multivalent mannosides are to be explored to study MR-sugar binding events.