Reader in Molecular Virology
Infection and Immunity
Antibody studies using virus particles displaying xeno-reactive antigens; alpha-Gal, Neu5Gc and SDa-like carbohydrate structures
Ilaria Nisoli1, Heide Kogelberg2, Christopher GA McGregor2, Guerard Byrne2, Yasuhiro Takeuchi1.
1Infection and Immunity, UCL, London, United Kingdom; 2Institute of Cardiovascular Science, UCL, London, United Kingdom
Healthy people as well as patients exposed to xenogeneic materials possess antibodies against various xeno-reactive carbohydrate antigens. Health implications of these antibodies are unclear in general, in xenotransplantation/medical device implant settings or in zoonotic infection. Eating excess red meat may have negative health effect by facilitating anti-Neu5Gc antibody response. Deterioration of animal derived implants, such as heart valves, is likely to be at least in part due to anti-carbohydrate antibody reaction. An issue in xenotransplantation safety is the effect of these antibodies on the potential zoonoses from genetically engineered animals lacking certain glycan antigens to animal handlers and to patients treated with live animal cells, tissues or organs.
It is well known that enveloped viruses, such as influenza, HIV and measles, incorporate host-cell dependent, surface antigens including glycoconjugates. We hypothesized that virus particles displaying specific carbohydrate structures can be used for quantification and functional characterization of such xeno-reactive antibodies.
We obtained human HEK293 cell lines bearing one of three glycan antigens, aGal (1), Neu5Gc (2) and SDa-like (3), by introducing porcine cDNA for GGTA1, CMAH, and β4GalNT2 genes. Subsequently lentiviral vector particles were produced from these cell lines. Expression of these carbohydrate structures on the cell surface was demonstrated by FACS staining using either specific lectins (for aGal and SDa-like) or chicken IgY antibody (for Neu5Gc). Incorporation and display of aGal carbohydrate on virus surface has been confirmed by a virus pull down assay so far.
These panels of viruses displaying different glycan antigens will be used in assays for antibody binding, complement mediated killing (1) and antibody mediated enhancement (ADE) of infection via Fc or complement receptors (4). These studies will identify potential effects of certain anti-glycan antibodies on viral infection and inform potential advantages and disadvantages for presence or absence of certain antigens in devices/tissues and their source animals. Some of these assays will be quantitative measurements for glycan specific antibody binding and function and may have some advantages over other antibody assays: e.g. complement-mediated virus killing assay has been demonstrated to be more sensitive, clear-cut and less labour intensive than a cell killing assay (1).
The EU FP7 Collaborative Project “TransLink”, contract # HEALTH-F4-2013-603049.
 Takeuchi et al. 1996. Nature 379:85-88.
 Byrne et al. 2011 Transplantation 91:287-292.
 Willey et al. 2011 Retrovirology 8:16.
 Scobie et al. 2013 J Immunol 191:2907-2915.
07:00 - 08:00
|Orals: Tolerance, Zoonosis||Antibody studies using virus particles displaying xeno-reactive antigens; alpha-Gal, Neu5Gc and SDa-like carbohydrate structures||Room 109|