A First-time in Human (FTIH) Study to Evaluate Safety, Tolerability, Pharmacokinetics and Target Engagement of GSK4528287 in Healthy Participants

Inclusion Criteria:

• Participants who are overtly healthy as determined by medical evaluation includingmedical history, physical examination, laboratory tests, and cardiac monitoring

• White blood cell greater than or equal to (>=) lower limit of normal (LLN),including both lymphocyte counts >= LLN and neutrophil counts >= LLN, at bothscreening and pre-dose (Day-1) Note: in cases where the test is abnormal, theparticipant may have the test repeated once and if their second test is normal, theywill be eligible. In the event a second test is also abnormal, the participant isnot eligible

• Electrocardiogram (ECG) with no clinically significant abnormality at the discretionof the investigator/designee

• Participants with a confirmed positive vaccination status for severe acuterespiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines as per local/site guidance

• SARS-CoV-2 screening test negative as per local guidance

• If dosing is during influenza season (October to April per local guidelines),participants who have not had a seasonal influenza vaccine must receive a medicinesand healthcare products regualtory agency (MHRA)-approved influenza vaccine at least 30 days before dosing

• Body weight >= 50 kilograms (kg) and body mass index (BMI) within the range 18-32kilograms per square meters (kg/m^2) (inclusive)

• Male and/or female of non-childbearing potential

• Male participants are eligible to participate if they agree to the following duringthe study intervention period and for 48 weeks after the single dose of studyintervention: refrain from donating sperm; be abstinent from heterosexualintercourse as their preferred and usual lifestyle (abstinent on a long term andpersistent basis) and agree to remain abstinent; or agree to use a male condom andshould also be advised of the benefit for a female partner to use a highly effectivemethod of contraception as a condom may break or leak when having sexual intercoursewith a woman of childbearing potential (WOCBP) who is not currently pregnant

• A female participant is eligible to participate if she is a woman ofnon-childbearing potential (WONCBP)

• Capable of giving signed informed consent

Exclusion Criteria:

• History or presence of/significant history of or current cardiovascular,respiratory, hepatic, renal, gastrointestinal, endocrine, hematologic, orneurological disorders capable of significantly altering the absorption, metabolism,or elimination of drugs; constituting a risk when taking the study intervention orinterfering with the interpretation of data

• Abnormal blood pressure as determined by the investigator

• Symptomatic herpes zoster within 3 months prior to screening

• Prior medical history of anaphylaxis or severe adverse reactions to vaccines

• Significant allergies to humanized monoclonal antibodies

• Clinically significant multiple or severe drug allergies, intolerance to topicalcorticosteroids, or severe post-treatment hypersensitivity reactions (including, butnot limited to, erythema multiforme major, linear Immunoglobulin A [IgA] dermatosis,toxic epidermal necrolysis, and exfoliative dermatitis)

• Immunodeficiency or autoimmunity assessed by medical history.

• A history of recurrent infections

• Treatment of any significant infection within 3 months prior to the first dose ofstudy drug, including both serious local infection (e.g., cellulitis, abscess) orsystemic infection (e.g., pneumonia, shingles)

• Any history of chronic infection including tuberculosis, hepatitis B, hepatitis C orhuman immunodeficiency virus (HIV)

• Any acute infection (including upper respriatory tract infection [URTI] and urinarytract infection [UTI]) which has not fully resolved within four weeks of dosing

• History of sensitivity to any of the study medications, or components thereof or ahistory of drug or other allergy that, in the opinion of the investigator orGlaxoSmithKline (GSK) medical monitor, poses a safety risk with regards toparticipation in the trial

• History of malignancy, including malignant or non-malignant skin cancer

• Prior moderate/severe SARS-CoV-2 infection requiring oxygen supplementation oradmission to hospital

• Treatment with biologic agents (such as monoclonal antibodies including marketeddrugs) within 3 months or 5 half-lives (whichever is longer) prior to dosing

• Antibiotics or antiviral therapy within 30 days of dosing

• Receipt of live vaccination within 1 month prior to screening or plan to receivelive vaccination during the study

• Past or intended use of over the counter or prescription medication including herbalmedications within 7 days prior to dosing

• The participant has participated in a clinical trial and has received aninvestigational product (IP) within the following time-period prior to the firstdosing day of the current study: 30 days, 5 half-lives or twice the duration of thebiological effect of the investigational product (whichever is longer)

• Exposure to more than 4 new chemical entities within 12 months prior to dosing

• Current enrolment or past participation in this clinical study.

• Participation in a clinical study that would result in donation of blood or bloodproducts in excess of 500 millilitres (mL) within a 56 day period

• A positive diagnostic Mycobacterium tuberculosis bacteria (MTB) test at screening (defined as positive QuantiFERON Gold test)

• Positive test for HIV antibody at screening

• Positive drug/alcohol test, including tetrahydrocannabinol, at screening or Day 1

• Positive smoke breath analyzer levels indicative of smoking history at screening andin house admission to the clinical research unit or regular use of tobacco- ornicotine-containing products (e.g., nicotine patches, vaporizing devices) within 6months prior to screening

• A positive confirmation of SARS CoV 2 infection or signs and symptoms suggestive ofSARS CoV 2 at screening or pre dose

• The participant is at high risk of MTB infection in the opinion of the Investigator.Risk factors include residing in a high prevalence area or having close contact witha person with confirmed MTB infection

• The participant has a phobia to needles

• Regular alcohol consumption within 6 months prior to study, defined as: An averageweekly intake of greater than (>)14 units of alcohol. One unit is equivalent to 8grams (g) of alcohol: a half pint (approximately 240 mL) of beer, 1 glass (125 mL)of wine or 1 measure (25 mL) of spirits

• Regular use of known drugs of abuse, including tetrahydrocannabinol

• Alanine aminotransferase (ALT or AST) >1.0*upper limit of normal (ULN)

• Total bilirubin >1.0ULN; Participants with Gilbert's syndrome can be included withtotal bilirubin >1.5ULN as long as direct bilirubin is less than or equal to (<=) 1.5*ULN

• Current or chronic history of liver disease or known hepatic or biliaryabnormalities (with the exception of Gilbert's syndrome or asymptomatic gallstones).

• Presence of hepatitis B surface antigen (HBsAg) or hepatitis B core antibody (HBcAb)at screening or Day -1 or within 3 months prior to first dose of study intervention.

• Positive hepatitis C antibody test result at screening or within 3 months prior tofirst dose of study intervention.

• Positive hepatitis C ribonucleic acid (RNA) test result at screening or within 3months prior to first dose of study intervention.

• QTcF (QT interval corrected for heart rate according to Fredericia's formula) >450milliseconds (msec).