Generation of human antigen-specific monoclonal IgM antibodies using vaccinated "human immune system" mice.
BACKGROUND
Passive transfer of antibodies not only provides immediate short-term protection against disease, but also can be exploited as a therapeutic tool. However, the 'humanization' of murine monoclonal antibodies (mAbs) is a time-consuming and expensive process that has the inherent drawback of potentially altering antigenic specificity and/or affinity. The immortalization of human B cells represents an alternative for obtaining human mAbs, but relies on the availability of biological samples from vaccinated individuals or convalescent patients. In this work we describe a novel approach to generate fully human mAbs by combining a humanized mouse model with a new B cell immortalization technique.


RESULTS
After transplantation with CD34+CD38⁻ human hematopoietic progenitor cells, BALB/c Rag2⁻/⁻IL-2Rγc⁻/⁻ mice acquire a human immune system and harbor B cells with a diverse IgM repertoire. "Human Immune System" mice were then immunized with two commercial vaccine antigens, tetanus toxoid and hepatitis B surface antigen. Sorted human CD19+CD27+ B cells were retrovirally transduced with the human B cell lymphoma (BCL)-6 and BCL-XL genes, and subsequently cultured in the presence of CD40-ligand and IL-21. This procedure allows generating stable B cell receptor-positive B cells that secrete immunoglobulins. We recovered stable B cell clones that produced IgM specific for tetanus toxoid and the hepatitis B surface antigen, respectively.


CONCLUSIONS
This work provides the proof-of-concept for the usefulness of this novel method based on the immunization of humanized mice for the rapid generation of human mAbs against a wide range of antigens.
Becker
Pablo D
PD
Department of Vaccinology and Applied Microbiology, Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany.
Legrand
Nicolas
N
van Geelen
Caroline M M
CM
Noerder
Miriam
M
Huntington
Nicholas D
ND
Lim
Annick
A
Yasuda
Etsuko
E
Diehl
Sean A
SA
Scheeren
Ferenc A
FA
Ott
Michael
M
Weijer
Kees
K
Wedemeyer
Heiner
H
Di Santo
James P
JP
Beaumont
Tim
T
Guzman
Carlos A
CA
Spits
Hergen
H
D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis*; D001402:B-Lymphocytes / Q000276:immunology*; D002461:Cell Line, Transformed; D002469:Cell Separation; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D007107:Immune System; D007075:Immunoglobulin M / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C
D000911:Antibodies, Monoclonal; D007075:Immunoglobulin M