Allergenic molecules
Cup a 1 is the only allergen from Arizona cypress included in the IUIS database as of July 2021. Cup a 1, used either a recombinant or a a purified molecule, is widely used as a marker of genuine sensitization to Cupressaceae (26). Further allergens from Arizona cypress pollen have been reported and characterized in the literature.
Name
|
Biochemical activity
|
Molecular weight (kDa)
|
Glycosylation
|
Major/minor allergen
|
Marker allergen
|
IUIS
|
Reference
|
---|
Cup a 1
|
Pectate lyase
|
43
|
Yes
|
Major
|
Yes
|
Yes
|
24
|
Cup a 2
|
Polygalacturonase
|
41 (fragment)
|
Yes
|
Major
|
No
|
No
|
1
|
Cup a 3
|
Thaumatin-like protein
|
21
|
No
|
Major
|
No
|
No
|
28
|
Cup a 4
|
Polcalcin
|
18
|
No
|
Minor
|
No
|
No
|
29
|
Name
|
Biochemical activity
|
Molecular weight (kDa)
|
Glycosylation
|
Major/minor allergen
|
Marker allergen
|
IUIS
|
Reference
|
---|
Although currently not characterized, an allergenic gibberellin-regulated protein is presumably expressed in Arizona cypress pollen, similarly to C. sempervirens (Cup s 7), J. ashei (Jun a 7), and Cryptomeria japonica (Cry j 7) (30,31).
Biomarkers of severity
Cup a 1 is the marker allergen for sensitization to Cupressaceae family including Arizona cypress and C. sempervirens (22,25,26). Polcalcin sensitization can be assayed using Phl p 7 or Bet v 4 as surrogates. In patients with suspected pollen – food cross-reactivity due to gibberellin-regulated proteins, Pru p 7 is the currently available marker (32).
Cross-reactivity
There is extensive cross-reactivity between Arizona cypress pollen and other members of the Cupressaceae family, due to high sequence identity and similarity between molecular allergens. Cross-reactivity with pollens outside the family is possible, mainly through polcalcin sensitization, but relatively infrequent for this minor allergen (9.6% Cup a 4 sensitization in cypress-allergic patients, ref 29). The carbohydrate moieties present on pectate lyase Cup a 1 and other major allergens of Cupressaceae family contribute to IgE binding, but their pathogenic role is not established. Pollen-food syndrome due to Cupressaceae primary sensitization has been suspected for a long time. Although multiple allergens could be involved, e.g. polygalacturonase, thaumatin-like protein, and gibberellin-regulated protein, formal demonstration has only been provided for the latter (31,32).