Human Anti-Feline Fel d 4 Monoclonal Antibody, clone 2F29

Background: Standardized methods to measure allergen exposure are essential to assess the relationship between exposure, sensitization, and asthma. Most studies have measured allergen levels in reservoir dust, although air samples may be more representative as a measure of inhaled allergen. The aim of this study was to define the relationship between mite, cat, and dog allergen content in the reservoir dust and the levels in the ambient air. Methods: Dust samples from the living-room floor (LF) and sofa (S) were collected in 127 homes: 62 without and 65 with pets (31 dogs, 34 cats). Air samples were taken in the same room, with a high-volume pump for 1 h (flow 60 l/min). Der p 1, Fel d 1, and Can f 1 were determined by mAb-based ELISA. Results: Airborne Der p 1 was below the detection limit (0.8 ng/m(3)) in all homes, with reservoir levels (GM and range) being 1.14 mu g/g (0.2-66) and 1.15 mu g/g (0.2-127) in LF and S, respectively. Airborne Can f 1 was detected in 40/62 homes without pets (range 0.6-12.4 ng/m(3)) and in all homes with dogs (range 0.5-99 ng/m(3)). In the multiple linear regression analysis, Can f 1 level in the LF was an independent correlate of the airborne Can f 1 (P = 0.01, homes with dogs; P = 0.04, homes without dogs). Fel d 1 was detected in the air in 16/62 homes without pets (range 0.16-1.8 ng/m(3)) and in all homes with cats (range 0.4-22.3 ng/m(3)). Fel d 1 level in the LF was an independent correlate of the airborne Fel d 1 in homes without cats (P = 0.008), but airborne levels in homes with cats did not correlate with reservoir levels. Conclusions: The aerodynamics of each allergen must be taken into account when assessing exposure: while levels in reservoir dust are the best available index for mite allergens, airborne levels might be more suitable for defining exposure to pets. If air samples are difficult to obtain, levels of Can f 1 and Fel d 1 in the LF samples should be used as a surrogate measure of personal exposure.

Background: Allergy to cat epithelia is highly prevalent, being the major recommendation for allergy sufferers its avoidance. However, this is not always feasible. Allergen specific immunotherapy is therefore recommended for these patients. The use of polymerized allergen extracts, allergoids, would allow to achieve the high allergen doses suggested to be effective while maintaining safety. Results: Cat native extract and its depigmented allergoid were manufactured and biochemically and immunochemically characterized. Protein and chromatographic profiles showed significant modification of the depigmented allergoid with respect to its corresponding native extract. However, the presence of different allergens (Fel d 1, Fel d 2, Fel d 3, Fel d 4 and Fel d 7) was confirmed in the allergoid. Differences in IgE- binding capacity were observed as loss of biological potency and lower stability of the IgE-allergen complex on surface plasmon resonance. The allergoid induced production of IgG antibodies able to block IgE-binding to native extract. Finally, studies carried out with peripheral- blood mononuclear cells from cat allergic patients showed that the allergoid induced IFN-y and IL-10 production similar to that induced by native extract. Conclusions: Cat depigmented allergoid induced production of cytokines involved in a Th1 and Treg response, was able to induce production of IgG-antibodies that blocks IgE-binding to cat native extract, and showed reduced interaction with IgE, suggesting greater safety than native extract while maintaining in vitro efficacy.