HLA-DQ6 and HLA-DQ8 transgenic mice respond to ragweed allergens and recognize a distinct set of epitopes on short and giant ragweed group 5 antigens.
We have investigated the genetic and molecular basis of immune responsiveness to short ragweed (SRW) (Ambrosia artemisiifolia) extract, and group 5 allergens from short and giant (Ambrosia trifida) ragweed using transgenic mice expressing DQ6 (HLA-DQA1*0103, HLA-DQB1*0601) and DQ8 (HLA-DQA1*0301, HLA-DQB1*0302) genes in class II knockout (A beta0) mice. Panels of overlapping peptides spanning the Amb a 5 and Amb t 5 Ags were synthesized. Mice were immunized with whole SRW extract or individual peptides s.c. and lymph node cells (LNC) were challenged in vitro. Strong T cell responses to SRW extract were measured in both HLA-DQ transgenic mice, while control, HLA-DQ6-/DQ8-/H-2A beta0, mice were unresponsive. IL-5 and IL-10 were the primary cytokines produced by in vitro challenged LNC of SRW-primed transgenic mice. HLA-DQ6-restricted T cell responses were detected to all three peptides of Amb t 5 and two determinants (residues 1-20 and 11-30) on Amb a 5. In contrast, LNC of HLA-DQ8 mice did not recognize peptide 11-30 of Amb t 5 Ag, but recognized several Amb a 5 determinants. The immune response in transgenic mice was dependent upon CD4+ T cells and was HLA-DQ restricted. Primed with purified Amb t 5, both transgenics recognized peptide 21-40, and an additional DQ6-restricted epitope was found within residue 1-20. SRW-immunized HLA-DQ6 mice respond to peptide 11-30 of Amb a 5, while HLA-DQ8 mice strongly recognize peptide 1-20. These results demonstrate the specificity of HLA class II polymorphism in allergen sensitivity and pave the way for developing antagonistic peptides for desensitization.
Department of Immunology, Mayo Clinic, Rochester, MN 55905, USA.
S P
SP
Chapoval
T
T
Neeno
C J
CJ
Krco
E V
EV
Marietta
J
J
Harders
C S
CS
David
D000485:Allergens / Q000008:administration & dosage / Q000276:immunology*; D000595:Amino Acid Sequence; D000818:Animals; D052179:Antigens, Plant; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D016207:Cytokines / Q000096:biosynthesis; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D006683:HLA-DQ Antigens / Q000235:genetics* / Q000276:immunology; D016056:Immunodominant Epitopes / Q000276:immunology; D007279:Injections, Subcutaneous; D008198:Lymph Nodes / Q000166:cytology / Q000276:immunology; D008213:Lymphocyte Activation / Q000235:genetics; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000276:immunology; D010455:Peptides / Q000008:administration & dosage / Q000276:immunology*; D010940:Plant Proteins / Q000008:administration & dosage / Q000276:immunology*; D011058:Pollen / Q000276:immunology*; D011108:Polymers; D018418:Th2 Cells / Q000378:metabolism
D000485:Allergens; D052179:Antigens, Plant; D016207:Cytokines; D018984:Epitopes, T-Lymphocyte; D006683:HLA-DQ Antigens; C063831:HLA-DQ6 antigen; C109756:HLA-DQ8 antigen; D016056:Immunodominant Epitopes; D010446:Peptide Fragments; D010455:Peptides; D010940:Plant Proteins; D011108:Polymers; C029134:short ragweed fraction A-D-glutamic acid-D-lysine polymer; C069543:group 5 allergens, Ambrosia