Abstracts summarizing recent research overseen by the WHO Advisory Committee on Variola Virus Research - 2003
Human Combinatorial Antibodies against Orthopoxviruses
N.V. Tikunova, E.I. Bovshik, T.E. Yun, E.V. Jirakovskaja, A.A. Ilyichev, V.V. Morozova, T.A. Batanova, E.F. Belanov., A.A. Guskov, L.S. Sandakhchiev.
State Research Center of Virology and Biotechnology Vector, Koltsovo, Novosibirsk region, 630559 Russia
Please direct all queries to the authors at the addresses given.
During the previous year, three independent collections of 18 human mini-antibodies specific to live variola virus-Ind-3a, 11 antibodies specific to variola virus-Butler, and 20 antibodies specific to vaccinia virus-Elstree had been obtained from the synthetic human scFv phage library by biopanning and selection.
During the current reporting period, Phagemid DNA from each clone has been examined by PCR and restriction analysis for perfect scFv gene presence. Pagemid DNAs bearing perfect genes were sequenced and unique antibodies were selected. All unique antibodies were assayed in ELISA for their binding with some strains of variola viruses: Ind-3a, Butler, Brazil 131, Congo-2 and Kuw-5.
From these strains variola viruses Butler and Brazil 131 are from the alastrim group. Antibody 2B2, selected against variola virus Butler, and antibody 9G2, selected against vaccinia virus Elstree, whose binding was stronger with both strains from the alastrim group than with the other strains, were found.
In addition, all the phage antibodies selected were assayed in binding reactions with other orthopoxviruses (vaccinia, cowpox and ectromelia viruses). The data obtained showed that the binding of the majority of the selected phage antibodies with different orthopoxviruses did not vary significantly except for several antibodies that bound different orthopoxvirus species with different activities.
All the phage antibodies selected against VARV and VACV were tested in the reactions of neutralization of viral infectivity in a monolayer of cell culture VeroE6 whereas VACV-Elstree, VARV-Ind3a and VARV-Butler were used as infectious agents. No neutralizing activities for the phage antibodies have been demonstrated, but it should be noted, that a phage antibody has a single antigen-binding site while at least two antigen-binding sites are necessary for virus neutralization usually.