**Involvement of Climatic Factors in the Allergen Expression in Olive Pollen**

Sonia Morales, Antonio Jesús Castro, María Isabel Rodríguez-García and Juan de Dios Alché

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/50077

### **1. Introduction**

56 Current Insights in Pollen Allergens

No. 21, pp. 15217-15222.

Villalba, M., Batanero, E., Monsalve, R.I., González de la Peña, M.A. Lahoz, C., & Rodríguez, R. (1994). Cloning and expression of Ole e I, the major allergen from olive tree pollen. Polymorphism analysis and tissue specificity. *Journal of Biological Chemistry*, Vol. 269,

> Olive allergen concentrations in the pollen grain are critical in allergic response of atopic patients. Existing evidence shows that climatic factors can influence pollen allergen content. To date, the influences of temperature and precipitations over the content of birch and olive pollens in their respective major allergens have been analyzed. Bet v 1, the major allergen of birch pollen, increased its expression (Buters et al. 2008) and presented a higher allergenicity (Ahlholm et al. 1998) while temperatures were elevated. Differently, the content in the major olive pollen allergen Ole e 1 showed no apparent correlation with either temperatures or precipitations (Fernández Caldas et al. 2007). However, a positive correlation between total allergenicity and rainfall occurring in winter months was found. This correlation was not analyzed independently for each pollen allergen.

> Our aim was to extend the observations carried out in olive pollen, by analyzing the effects of climate parameters over the expression of four olive pollen allergens. Using a recently developed multiplex western blotting system for the assessment of allergenic molecules (Morales et al. 2012), we have simultaneously detected and quantified two major (Ole e 1 and Ole e 9) and two minor allergens (Ole e 2 and Ole e 5) in the pollen extracts from seven olive cultivars collected along 4-7 consecutive years. The considered climatic variables included temperature, precipitation, number of rain days and humidity. Data were provided by the Spanish network for the temporal observation of ecosystems (REDOTE). Correlations between the allergen contents (both individually and all inclusive) and climate variables were studied by applying Spearman correlation tests. Results showed significant variations in the expression of the four allergens in the seven cultivars throughout the years of the analysis. All these positive correlations corresponded exactly to the period of time starting the winter prior to each flowering period to the end of period (this is, December from the previous year to June).

© 2012 Morales et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2012 Morales et al., licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

These results are discussed as regard to their putative incidence in the development of symptoms by patients, the requirements for medical assistance and the rates of admission into clinical centres and hospitals. Agronomical implications in olive sexual reproduction, including fruit setting and fruit production, are also discussed.

Involvement of Climatic Factors in the Allergen Expression in Olive Pollen 59

unconjugated Fab antibody fragments for blocking rabbit primary antibodies, and fluorescence-based detection. These changes allowed an accurate and reliable comparative

Imaging was carried out with a Pharos FX Plus Molecular Imager (Bio-Rad) using the Quantity One v4.6.2 software (Bio-Rad). The intensity of each fluorescent band was

Climate parameters were obtained from the weather tracking station situated at Córdoba airport (Spain) during the years 2000 to 2007. Information was extracted from the Spanish

Continuous variables were subjected to a study of normality distribution by using the Kolmorov-Smirnov test. Associations between continuous variables (non-normal distribution) were described by analysis of bivariate Spearman correlation (two-tailed).

**3.1. Multiplex determination of year-to-year allergen expression in seven olive** 

Figure 1A shows the protein profiles of the extracts analyzed after SDS-PAGE and silver staining. The different panels correspond to the cultivars analyzed between the years 2000 and 2007. Bands were observed in the range of 15 to 75 kDa. Clear quantitative differences were distinguished, from which the most conspicuous were those in the bands of 20 kDa and 18.4 kDa among de different years, with the exception of cultivars 'Arbequina', 'Verdial de Huévar' and 'Hojiblanca', in which the Ole e 1 bands were not well identified after silver

Allergenic profiles were assessed by multiplex immunotransference (Figure 1B). The cultivars 'Arbequina' and 'Hojiblanca' displayed two Ole e 1 forms (20 kDa and 18.4 kDa) in contrast with the remaining cultivars, were the three major forms of Ole e 1 (22 kDa, 20 kDa and 18.4 kDa) were distinguished. Differences in the expression of this allergen depending

Ole e 2 was visualized in all cultivars in the form of two bands with sizes of 15.1 kDa and 14 kDa, with the exception of the 'Verdial de Vélez' cultivar, in which only the 15.1 kDa band was present. As described for Ole e 1, the presence of noticeable differences in the

staining. The remaining allergens studied were not identified after silver staining.

calculated using the quantitation tools of the Quantity One v4.6.2 software.

quantitation of these allergens among pollen protein samples.

**2.4. Absolute and relative quantitation of allergens** 

long term ecological research network (REDOTE).

Significant correlation was considered P<0.05.

on the year of pollen collection can be easily noticed.

**2.5. Climate parameters** 

**2.6. Statistical analysis** 

**3. Results** 

**cultivars** 
