This is an exploratory study to characterize the ex vivo immune response to RO6871765 or RO7011785 stimulation of peripheral blood mononuclear cells (PBMCs) extracted from healthy volunteers and chronic hepatitis B (CHB) patients.

Inclusion Criteria:

All population:

• Chinese population
• Adequate hematological function: platelet count greater than or equal to (>=) 100*10^9 per liter (/L), hemoglobin (Hb) >= 12 grams/deciliter (g/dL) (male) or >= 11 g/dL (female), white blood cell (WBC) count >= 4*10^9/L and <= 11*10^9/L

Healthy volunteers:

• Absence of evidence of any active or chronic disease
• Negative hepatitis B virus deoxyribonucleic acid (HBV DNA), hepatitis B surface antigen (HBsAg), hepatitis B surface antibody (HBsAb), hepatitis B envelope antigen (HBeAg), hepatitis B envelope antiody (HBeAb) and hepatitis B core antibody (HBcAb)
• Adequate liver function: transaminases alanine aminotransferase (ALT) <= 1.0 times the upper limit of normal (ULN)

Treatment naïve CHB patients:

• HBsAg-positive (>=250 international unit/milliliter [IU/mL]), compensated liver function, non-cirrhotic
• HBeAg-positive, HBV DNA >= 200,000 IU/ml or equivalent copies/mL, ALT >1.5 times the ULN and ALT <8 times the ULN

HBeAg-negative nucleoside/nucleotide analogue-treated CHB patients:

• Subjects who HBeAg-seroconverted on nucleoside/nucleotide analogue therapy (treatment for 1 to 3 years prior to enrollment) with HBV DNA <90 IU/mL or below a detection level acceptable by both the sponsor and investigator for at least the preceding 6 months; HBeAg negative and HBeAb positive
• HBsAg-positive (>=250 IU/mL), compensated liver function, non-cirrhotic -ALT <= 1*ULN

Exclusion Criteria:

• Use of steroids or other immune suppressive agents within the last 4 weeks that would impact the number/functions of white blood cells (WBC)
• Any other diseases or clinical laboratory finding giving reasonable suspicion of a disease or condition (including, but not limited to, cancer, lupus erythematosus, rheumatoid arthritis, or other autoimmune disease) that could confound the result of the study
• Positive Hepatitis A immunoglobulin M (IgM) antibody, Hepatitis C antibody (HCV Ab) or human immunodeficiency virus (HIV) at screening
• Significant acute infection, example; influenza, acute gastrointestinal symptoms or any other clinically significant illness within 2 weeks
• Previous/concurrent treatment with interferon-based therapy for CHB

Chinese population: healthy volunteers, treatment naive CHB patients and nucleoside or nucleotide analogue treated CHB patients