Production of an anti-severe acute respiratory syndrome (SARS) coronavirus human monoclonal antibody Fab fragment by using a combinatorial immunoglobulin gene library derived from patients who recovered from SARS.

A combinatorial human immunoglobulin gene library was constructed from the peripheral lymphocytes of two patients who recovered from severe acute respiratory syndrome (SARS). The library was screened for the production of Fab antibody fragments to a recombinant spike protein of SARS-associated coronavirus (SARS-CoV). One Fab clone, AS3-3, reacted with the spike protein in an enzyme-linked immunosorbent assay. The dissociation constant of AS3-3 was 1.98 x 10(-8) M. Immunofluorescent microscopy revealed that it reacted with SARS-CoV-infected cells. The library seems to be a potent tool for the production of human antibodies to SARS-CoV.