Bacterial expression of neutralizing mouse monoclonal antibody Fab fragments to Hantaan virus.
We amplified by polymerase chain reaction the heavy and light chain antibody genes of two mouse hybridomas secreting neutralizing monoclonal antibodies (MAbs) to the G1 or G2 envelope proteins of Hantaan virus, cloned them into the phagemid vector pComb3, and expressed them in bacteria to yield Fab fragments. Expressed Fab fragments had the same antigenic specificities for Hantaan and Seoul viruses as the complete parent MAbs and were able to neutralize Hantaan virus in plaque-reduction neutralization assays. The authentic MAb to G2 (HCO2) could passively protect hamsters from challenge with Hantaan virus when neutralizing antibody titers of at least 1:10 were detected in the animals' sera just prior to challenge. In contrast, although 1:10 neutralization titers were also detected in hamsters receiving passively transferred, Escherichia coli-expressed HCO2 Fab, these animals were not protected from infection with Hantaan virus. Similarly, passive transfer of the HCO2 Mab on Days 1 through 4 after infection prevented antigen deposition in hamster lungs and kidneys but passive transfer of the recombinant HCO2 Fab did not. The results suggest that although neutralization by IgG antibodies correlates with protection in hamsters, the same may not be true for neutralizing Fab fragments.
Liang
M
M
Virology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland 21702-5011, USA.
Chu
Y K
YK
Schmaljohn
C
C
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000008:administration & dosage / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification; D000914:Antibodies, Viral / Q000235:genetics* / Q000276:immunology; D000918:Antibody Specificity; D001483:Base Sequence; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D006224:Cricetinae; D017931:DNA Primers; D004926:Escherichia coli; D018063:Hantaan virus / Q000276:immunology*; D006480:Hemorrhagic Fever with Renal Syndrome / Q000276:immunology / Q000517:prevention & control; D006801:Humans; D007116:Immunization, Passive; D007140:Immunoglobulin Fab Fragments / Q000008:administration & dosage / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification; D007143:Immunoglobulin Heavy Chains / Q000235:genetics / Q000276:immunology; D007147:Immunoglobulin Light Chains / Q000235:genetics / Q000276:immunology; D008647:Mesocricetus; D051379:Mice; D008969:Molecular Sequence Data; D009500:Neutralization Tests; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D014709:Vero Cells
D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D017931:DNA Primers; D007140:Immunoglobulin Fab Fragments; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D011993:Recombinant Fusion Proteins