A LAIR1 insertion generates broadly reactive antibodies against malaria variant antigens

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Item Type:	Article
Title:	A LAIR1 insertion generates broadly reactive antibodies against malaria variant antigens
Creators Name:	Tan, J., Pieper, K., Piccoli, L., Abdi, A., Foglierini, M., Geiger, R., Tully, C.M., Jarrossay, D., Ndungu, F.M., Wambua, J., Bejon, P., Silacci Fregni, C., Fernandez-Rodriguez, B., Barbieri, S., Bianchi, S., Marsh, K., Thathy, V., Corti, D., Sallusto, F., Bull, P. and Lanzavecchia, A.
Abstract:	Plasmodium falciparum antigens expressed on the surface of infected erythrocytes are important targets of naturally acquired immunity against malaria, but their high number and variability provide the pathogen with a powerful means of escape from host antibodies. Although broadly reactive antibodies against these antigens could be useful as therapeutics and in vaccine design, their identification has proven elusive. Here we report the isolation of human monoclonal antibodies that recognize erythrocytes infected by different P. falciparum isolates and opsonize these cells by binding to members of the RIFIN family. These antibodies acquired broad reactivity through a novel mechanism of insertion of a large DNA fragment between the V and DJ segments. The insert, which is both necessary and sufficient for binding to RIFINs, encodes the entire 98 amino acid collagen-binding domain of LAIR1, an immunoglobulin superfamily inhibitory receptor encoded on chromosome 19. In each of the two donors studied, the antibodies are produced by a single expanded B-cell clone and carry distinct somatic mutations in the LAIR1 domain that abolish binding to collagen and increase binding to infected erythrocytes. These findings illustrate, with a biologically relevant example, a novel mechanism of antibody diversification by interchromosomal DNA transposition and demonstrate the existence of conserved epitopes that may be suitable candidates for the development of a malaria vaccine.
Keywords:	Amino Acid Sequence, Antibody Specificity, Antigenic Variation, B-Lymphocyte Epitopes, B-Lymphocytes, Clone Cells, Collagen, Conserved Sequence, DNA Transposable Elements, Erythrocytes, Immunologic Receptors, Insertional Mutagenesis, Kenya, Malaria, Malaria Vaccines, Membrane Proteins, Molecular Sequence Data, Monoclonal Antibodies, Plasmodium falciparum, Protozoan Antigens, Protozoan Proteins, Tertiary Protein Structure
Source:	Nature
ISSN:	0028-0836
Publisher:	Nature Publishing Group
Volume:	529
Number:	7584
Page Range:	105-109
Date:	7 January 2016
Official Publication:	https://doi.org/10.1038/nature16450
PubMed:	View item in PubMed

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