Fel d1 Blocking Antibodies: A Novel Method to Reduce IgE-Mediated Allergy to Cats.

Fel d1 is an important allergen produced by cats that causes IgE reactions in up to 95% of cat-allergic adults. Immunotherapy to reduce human allergy to cats has demonstrated that people have the capacity to produce allergen-specific neutralizing antibodies that block IgE-mediated allergic responses. We wished to determine if "blocking" antibodies could be used to reduce the IgE binding ability of cat allergens prior to their exposure to humans. Here, we describe the characterization of Fel d1-specific antibodies. We demonstrated the efficacy of a rabbit polyclonal and an allergen-specific chicken IgY to bind to Fel d1 in cat saliva and block Fel d1-IgE binding and IgE-mediated basophil degranulation. Fel d1 blocking antibodies offer a new and exciting approach to the neutralization of cat allergens.

Anti-Fel d1 immunoglobulin Y antibody-containing egg ingredient lowers allergen levels in cat saliva.

OBJECTIVES: Fel d1 is the major cat allergen, causing IgE reactions in up to 90% of cat-allergic adults. Fel d1 secreted in saliva is spread to the haircoat during grooming. Current management includes attempts to reduce or eliminate exposure to Fel d1. A novel approach to reducing immunologically active Fel d1 (aFel d1) exposure, which involves binding the Fel d1 with an anti-Fel d1-specific polyclonal egg IgY antibody (sIgY), was evaluated. The hypothesis was that saliva from cats fed diets containing this sIgY would show a significant reduction in aFel d1. METHODS: Two trials in cats were completed. In trial 1, saliva was collected 0, 1, 3 and 5 h post-feeding during a 2 week baseline and subsequent 6 week treatment period. Trial 2 included a control and treatment group, and saliva was collected once daily. Trial 2 cats were fed the control diet during a 1 week baseline period, and then fed either control or sIgY diet during the 4 week treatment period. Fel d1-specific ELISA was used to measure salivary aFel d1. Data were analysed using repeated-measures ANOVA and a linear mixed-model analysis. RESULTS: Salivary aFel d1 decreased post-treatment in both trials. There were no differences in aFel d1 based on time of collection relative to feeding in trial 1. In trial 2, 82% of treatment group cats showed a decrease in aFel d1 of at least 20% from baseline vs just 38% of control cats. Only one (9%) treatment cat showed an increase in aFel d1 vs 63% of control cats. CONCLUSIONS AND RELEVANCE: Feeding sIgY significantly reduced aFel d1 in the saliva of cats within 3 weeks. Although additional research is needed, these findings show promise for an alternative approach to the management of allergies to cats.

Reduction of active Fel d1 from cats using an antiFel d1 egg IgY antibody.

BACKGROUND: Fel d1 is the most important allergen from cats. Fel d1 is produced primarily in saliva and spread to the haircoat during grooming and then transferred to the environment via hair and dander. OBJECTIVES: A novel approach to reducing allergenic Fel d1 exposure was evaluated, involving binding the Fel d1 with an anti-Fel d1 polyclonal egg IgY antibody. The hypothesis was that hair from cats who had been fed foods containing anti-Fel d1 IgY would show a significant reduction in active Fel d1 (aFel d1). METHODS: Hair collected from 105 cats completing a 12-week study was evaluated for aFel d1 via ELISA. Hair was collected four times over a 2-week baseline period, then weekly during the 10 week treatment period during which cats consumed a food containing the anti-Fel d1 IgY. RESULTS: Baseline aFel d1 (µg/g hair) varied greatly among the cats in this study. From week 3, there was a significant reduction in mean aFel d1 with an overall average decrease of 47% by week 10, ranging from a 33-71% decrease vs baseline. Cats with the highest baseline aFel d1 showed the greatest decrease in aFel d1. CONCLUSIONS & CLINICAL IMPLICATIONS: Feeding anti-Fel d1 IgY to cats successfully reduced aFel d1 on their haircoat with the greatest decreases observed in cats with initially high levels. Feeding a diet with anti Fel d1 IgY significantly reduced the active Fel d1 on the hair of cats.

Effect of supplementation with Enterococcus faecium (SF68) on immune functions in cats.

T evaluate the effect of supplementation with Enterococcus faecium strain SF68 (NCIMB10415) on immune function, responses to a multivalent vaccine were investigated in kittens given palatability enhancer with or without E. faecium SF68 daily. E. faecium SF68 was detected in the feces of seven of nine treated cats. Supplementation of kittens with E. faecium SF68 did not affect developmental parameters. The percentage of CD4+ lymphocytes was significantly higher in the treatment group. There were no statistical differences in measurements of any other nonspecific or specific immune parameters between groups.