Assess the Safety, Tolerability and Pharmacokinetics of AZD5055 Following Single and Multiple Ascending Doses in Healthy Participants

Inclusion Criteria * Healthy male and female (of non-childbearing potential) subjects aged Part 1 (SAD): 18 - 55 years; Part 2 (MAD): 18 - 55 for male and 18 -49 for females, inclusive, with suitable veins for cannulation or repeated venipuncture. * Female subjects must have a negative pregnancy test. * Have a BMI between 18 and 30 kg/m2 inclusive and weigh at least 50 kg. * Male subjects and their women of childbearing potential partners must be willing to use highly effective contraception measures and must refrain from donating sperm or fathering a child from the first day of dosing until 17 days after the last dose of Investigational medicinal product. Exclusion Criteria * History of any clinically important disease or disorder, or a major medical/surgical procedure or significant trauma within 4 weeks of the first dose of IMP. * Untreated tuberculosis (TB) or a positive result for the interferon gamma release assay (ie, QuantiFERON TB Gold). * A positive result for serum hepatitis B surface antigen, hepatitis B core antibody, or hepatitis C antibody, at the Screening Visit. * Ongoing acquired or inherited immunodeficiency disorders, including but not limited to HIV or common variable immunodeficiency, or the subject is taking immune replacement therapy. * Individuals with chronic infections (eg, urinary tract infection) or who are at increased risk of infection (eg, surgery, trauma, severe dental disease, or significant infection) within 30 days of screening. * Histor…