Cross-reactivity among conifer pollens.
BACKGROUND
There are increasing reports of Cupressaceae pollinosis from various geographic areas. Cross-reactivity among a limited number of species within the Cupressaceae family has been suggested. Juniperus ashei (mountain cedar) is the leading cause of respiratory allergy in South Texas.


OBJECTIVE
This study examines in vivo and in vitro cross-reactivity among 12 Cupressaceae species, one Taxodiaceae species, one Pinaceae species, and an angiosperm.


METHODS
Cross-reactivity among pollen extracts of mountain cedar (MC) and the other 14 trees was investigated by: (1) prick skin testing of each tree pollen extract in ten patients with MC pollinosis. (2) Ouchterlony gel immunodiffusion employing rabbit antisera to MC. (3) IgE immunoblotting using high-titer MC pooled human sera, and immunoblot inhibition after pre-incubation with MC protein. (4) Monoclonal antibody immunoblotting using a murine monoclonal antibody with strong affinity for the gp40 major allergen of MC.


RESULTS
Positive skin wheal-and-flare responses occurred to all 12 Cupressaceae and Japanese cedar (the Taxodiaceae), but not to the Pinaceae or the angiosperm. In Ouchterlony gels, lines of identity or partial identity formed between MC and all pollens except the Pinaceae and the angiosperm. Immunoblots demonstrated IgE binding to the 40 to 42 kD protein in each Cupressaceae, and to a parallel band in Japanese cedar at 43 to 46 kD. Immunoblot inhibition by MC pollen was complete for all trees. The monoclonal bound both the 40 to 42 kD protein in 11 of 12 Cupressaceae species and the 46 kD band in Japanese cedar, but bound no protein bands in the Pinaceae or the angiosperm.


CONCLUSIONS
Pollen proteins of the 12 Cupressaceae (including MC) and the Taxodiaceae (Japanese cedar) are extensively cross-reactive. In particular, the MC major allergen, gp40, is cross-reactive with 40 to 42 kD proteins of the other Cupressaceae and with the Japanese cedar major allergen of 46 kD. Component-based immunotherapy may someday allow a standard treatment for both Juniper-allergic and C. japonica-allergic patients.
Schwietz
L A
LA
Allergy-Immunology Department, Wilford Hall Medical Center, Lackland AFB, Texas, USA.
Goetz
D W
DW
Whisman
B A
BA
Reid
M J
MJ
D000818:Animals; D003429:Cross Reactions; D006801:Humans; D005779:Immunodiffusion; D007073:Immunoglobulin E / Q000097:blood; D008970:Molecular Weight; D010940:Plant Proteins / Q000276:immunology*; D011058:Pollen / Q000276:immunology*; D011817:Rabbits; D012882:Skin Tests
D010940:Plant Proteins; D007073:Immunoglobulin E