Allergenic Extract Standardized Cat Hair AP in an Allergic Rhinitis Model.

Inclusion Criteria: To be considered for inclusion in this study, all participants must be: * A healthy, ambulatory male, female, or intersex volunteer between the ages of 18 to 70 years of age. * Able to understand and willing to provide written informed consent. * Able and willing to comply with study requirements. To be enrolled as an allergic participant, participants must: * Have a minimum 2-year history of AR symptoms upon exposure to cats. * Have a positive skin prick response to AP cat allergen, defined as a wheal diameter ≥ 5 mm compared to the negative control wheal. This result must be achieved at visit 1. * Have a TNSS of greater than or equal to 8/12 and at least a 50% drop in PNIF in response to the allergen titration challenge at visit 1. To be enrolled as a non-allergic participant, participants must: * Produce a negative skin test response to a panel of relevant aeroallergens tested at visit 1 or within 12 months before visit 1 at the research site. * Produce a negative Nasal Allergen Challenge, defined by a TNSS response of less than 4/12 and a PNIF reduction of less than or equal to 20% after 10 minutes in response to the highest allergen concentration at visit 1. Exclusion Criteria: * Participant has abnormalities detected on physical examination considered by the investigator to be clinically significant. * Participant has a history of any disease or disorder that, in the judgement of the investigator, would impact the participant's safety or the results of the study. * Participant has a significant history of alcohol or drug abuse in the judgment of the Principal Investigator or delegate. * Participant is pregnant, lactating, or actively trying to become pregnant. * Participant is unable to comply with the washout periods for restricted medications. * Participant has signs/symptoms of active seasonal AR or is allergic to a seasonal allergen that is present in the outdoor environment during visit 1 and visit 2 and which the Principal Investigator judges would impact the outcome of the study. * Participant has any structural nasal abnormalities or nasal polyps on examination or a history of frequent nose bleeding, as determined by a nasal examination at screening and prior to the NAC, in the judgement of the principal investigator. * Participant has undergone nasal surgery within the previous 3 months before visit 1. * Participant has experienced an upper or lower respiratory infection within 2 weeks prior to the NAC visit. * Participant exhibits any signs or symptoms of a respiratory infection prior to any visit, as per Principal Investigator judgement. * Participant reports a TNSS of greater than or equal to 4 prior to the titration challenge at visit 1 or immediately prior to allergen challenge at visit 2, as per Principal Investigator judgement. * Participant reports a TNSS change of greater than 2 from baseline, after the diluent challenge at visit 1. * Participants with asthma requiring the use of a short-acting beta agonist greater than twice a week (unless for viral asthma) or with severe asthma requiring maintenance high doses of inhaled or oral corticosteroids or biologic therapy (Omalizumab/Mepolizumab/Resilizumab). * Participant has a history of cat allergen induced asthma, unless well controlled on low-dose inhaled corticosteroids or PRN inhaled corticosteroid/long-acting beta-agonist as per Principal Investigator discretion. * Participant is currently receiving cat allergen specific immunotherapy or concluded a course of cat immunotherapy in the last 3 years. * Participant has a history of positive test results for HIV, Tuberculosis (not due to vaccination), Hepatitis B (not due to vaccination) or Hepatitis C. * Participant has received an investigational product within the previous 30 days. * Participant is unable and/or unlikely to comprehend and/or follow the protocol over the duration of the study. Participant is unwilling to attend study visits or adhere to the study protocol, in the judgement of the Principal investigator.