Previous Article | Next Article 
Infection and Immunity, July 2007, p. 3614-3620, Vol. 75, No. 7
0019-9567/07/$08.00+0 doi:10.1128/IAI.00062-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.
Production of High-Affinity Human Monoclonal Antibody Fab Fragments to the 19-Kilodalton C-Terminal Merozoite Surface Protein 1 of Plasmodium falciparum
Xun-Jia Cheng,1,2
Hitoshi Hayasaka,1
Katsuomi Watanabe,1
Yan-Lin Tao,2
Jin-Ye Liu,2
Hideo Tsukamoto,3
Toshihiro Horii,4
Kazuyuki Tanabe,4 and
Hiroshi Tachibana1*
Department of Infectious Diseases,1 Teaching and Research Support Center, Tokai University School of Medicine, Isehara, Japan,3 Department of Medical Microbiology and Parasitology, Fudan University School of Medicine, Shanghai, China,2 Research Institute for Microbial Diseases, Osaka University, Osaka, Japan4
Received 12 January 2007/ Returned for modification 17 February 2007/ Accepted 13 April 2007
A combinatorial immunoglobulin gene library was constructed from peripheral blood lymphocytes of eight patients infected with Plasmodium falciparum and was screened for the production of human monoclonal antibody Fab fragments to the C-terminal 19-kDa fragment of P. falciparum merozoite surface protein 1 (MSP-119). Three Fab clones recognized recombinant MSP-119 under nonreducing conditions. Indirect immunofluorescence microscopy demonstrated that three Fab clones stained the surfaces of late trophozoites/schizonts and merozoites of the FCR3 and 3D7 strains, suggesting the Fabs' reactivities to a conserved epitope. Sequence analysis of the heavy-chain genes revealed that the closest germ line V segments were VH1-8 and VH7-81, with 91% to 98% homology. The closest germ line D segment was D3-10, and the closest germ line J segment was JH4 or JH5, with 90% to 97% homology. In the light-chain genes, the closest germ line V segment was A27 for the J
2, J4, and J5 segments. The dissociation constants of these Fab fragments for recombinant MSP-119 ranged from 1.09 x 10–9 to 2.66 x 10–9 M. The binding of the three Fab fragments to MSP-119 was competitively inhibited by the anti-MSP-119 mouse monoclonal antibody 12.8, which inhibits erythrocyte invasion by merozoites. However, the human Fab fragment with the highest affinity did not inhibit in vitro growth of P. falciparum. This is the first report of gene analysis and bacterial expression of human monoclonal antibodies to P. falciparum MSP-119. The combinatorial immunoglobulin gene library derived from malaria patients provides a potential tool for producing high-affinity human antibodies specific for P. falciparum.
* Corresponding author. Mailing address: Department of Infectious Diseases, Tokai University School of Medicine, Isehara, Kanagawa 259-1193, Japan. Phone: 81 (463) 93-1121. Fax: 81 (463) 95-5450. E-mail: htachiba{at}is.icc.u-tokai.ac.jp
Published ahead of print on 23 April 2007.
Infection and Immunity, July 2007, p. 3614-3620, Vol. 75, No. 7
0019-9567/07/$08.00+0 doi:10.1128/IAI.00062-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»