"Hijacking" the thyrotropin receptor: A chimeric receptor-lysosome associated membrane protein enhances deoxyribonucleic acid vaccination and induces Graves' hyperthyroidism.
Naked DNA vaccination with the TSH receptor (TSHR) does not, in most studies, induce TSHR antibodies and never induces hyperthyroidism in BALB/c mice. Proteins expressed endogenously by vaccination are preferentially presented by major histocompatibility complex class I, but optimal T cell help for antibody production requires lysosomal processing and major histocompatibility complex class II presentation. To divert protein expression to lysosomes, we constructed a plasmid with the TSHR ectodomain spliced between the signal peptide and transmembrane-intracellular region of lysosome-associated membrane protein (LAMP)-1, a lysosome-associated membrane protein. BALB/c mice pretreated with cardiotoxin were primed intramuscularly using this LAMP-TSHR chimera and boosted twice with DNA encoding wild-type TSHR, TSHR A-subunit, or LAMP-TSHR. With each protocol, spleen cells responded to TSHR antigen by secreting interferon-gamma, and 60% or more mice had TSHR antibodies detectable by ELISA. TSH binding inhibitory activity was present in seven, four, and two of 10 mice boosted with TSHR A-subunit, LAMP-TSHR, or wild-type TSHR, respectively. Importantly, six of 30 mice had elevated T4 levels and goiter (5 of 6 with detectable thyroid-stimulating antibodies). Injecting LAMP-TSHR intradermally without cardiotoxin pretreatment induced TSHR antibodies detectable by ELISA but not by TSH binding inhibitory activity, and none became hyperthyroid. These findings are consistent with a role for cardiotoxin-recruited macrophages in which (unlike in fibroblasts) LAMP-TSHR can be expressed intracellularly and on the cell surface. In conclusion, hijacking the TSHR to lysosomes enhances T cell responses and TSHR antibody generation and induces Graves'-like hyperthyroidism in BALB/c mice by intramuscular naked DNA vaccination.
Autoimmune Disease Unit, Cedars-Sinai Research Institute and University of California, Los Angeles School of Medicine, Los Angeles, California 90048, USA.
Pavel N
PN
Pichurin
Gregorio D
GD
Chazenbalk
Holly
H
Aliesky
Oxana
O
Pichurina
Basil
B
Rapoport
Sandra M
SM
McLachlan
D000818:Animals; D001323:Autoantibodies; D016466:CHO Cells; D015816:Cell Adhesion Molecules, Neuronal / Q000235:genetics; D006224:Cricetinae; D005260:Female; D058851:GPI-Linked Proteins; D006111:Graves Disease / Q000276:immunology* / Q000503:physiopathology*; D007156:Immunologic Memory / Q000502:physiology; D007273:Injections, Intramuscular; D008247:Lysosomes / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D010957:Plasmids; D011989:Receptors, Thyrotropin / Q000235:genetics* / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology; D013154:Spleen / Q000166:cytology / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology / Q000494:pharmacology*
D001323:Autoantibodies; D015816:Cell Adhesion Molecules, Neuronal; D058851:GPI-Linked Proteins; D011989:Receptors, Thyrotropin; D011993:Recombinant Fusion Proteins; D019444:Vaccines, DNA; C095362:limbic system-associated membrane protein