This is an open-label study to examine the safety and immunogenicity of synthetic DNAs encoding NP-GT8 and IL-12 with or without a TLR-agonist-adjuvanted Env Trimer 4571 boost in adults without HIV. The primary hypothesis is that vaccination with this recombinant DNA vaccine encoding a germline-targeting epitope followed by a trimeric protein boost will elicit VRC01-class B-cell responses as well as antigen-specific T-cell responses.

Inclusion Criteria:

• Able and willing to complete the informed consent process, including an Assessment of Understanding (AoU): volunteer demonstrates understanding of this study; completes a questionnaire prior to first vaccination with verbal demonstration of understanding of all questionnaire items answered incorrectly.

• 18 to 55 years old, inclusive, on day of enrollment.

• Available for clinic follow-up through the last clinic visit and willing to be contacted at least 12 months after the last vaccine administration.

• Willing to undergo leukapheresis.

• Agrees not to enroll in another study of an investigational agent during participation in the trial.

• In good general health according to the clinical judgement of the site investigator.

• Physical examination and laboratory results without clinically significant findings that would interfere with assessment of safety or reactogenicity in the clinical judgement of the site investigator.

• Assessed as low risk for HIV acquisition per low-risk guidelines, agrees to discuss HIV-infection risks, agrees to risk-reduction counseling, and agrees to avoid behaviors associated with high risk of HIV exposure through the final study visit. Low risk may include persons stably taking HIV pre-exposure prophylaxis (PrEP) as prescribed for 6 months or longer.

• Hemoglobin:

  • ≥ 11.0 g/dL for volunteers who were assigned female sex at birth.
  • ≥ 13.0 g/dL for volunteers who were assigned male sex at birth and transgender males who have been on hormone therapy for more than 6 consecutive months.
  • ≥ 12.0 g/dL for transgender females who have been on hormone therapy for more than 6 consecutive months.
  • For transgender participants who have been on hormone therapy for less than 6 consecutive months, determine hemoglobin eligibility based on the sex assigned at birth.

• Platelets = 125,000-550,000/mm3

• White blood cell (WBC) count = 2,500-12,000/mm3 (not exclusionary: if count greater than 12,000 with investigation showing general good health and PSRT approval). The Leukapheresis Center may impose a higher lower limit of 3,500/mm3

• Alanine aminotransferase (ALT) < 2.5 x upper limit of normal (ULN) based on the institutional normal range.

• Serum creatinine ≤ 1.1 x ULN based on the institutional normal range.

• Corrected total serum calcium level of > 8.5 mg/dL.

• Blood pressure in the range of 90 to < 140 mmHg systolic and 50 to < 90 mmHg diastolic.

• Negative results for HIV infection by a US Food and Drug Administration (FDA)-approved enzyme immunoassay (EIA) or chemiluminescent microparticle immunoassay (CMIA).

• Negative for anti-Hepatitis C Abs (anti-HCV), or negative HCV nucleic acid test (NAT) if anti-HCV Abs are detected.

• Negative for Hepatitis B surface antigen.

• For a volunteer capable of becoming pregnant:

  • Volunteers who were assigned female sex at birth and are of reproductive potential must agree to use effective means of birth control from at least 21 days prior to enrollment through 8 weeks after their last vaccination timepoint.
  • Has negative beta human chorionic gonadotropin (β-HCG) pregnancy test (urine or serum) on day of enrollment.

Exclusion Criteria:

• Volunteer who is breast-feeding or pregnant.

• Morbid obesity. Enrollment of individuals with body mass index (BMI) that is

  ≥ 40, whom the site investigator assesses are in good health, may be considered by PSRT on a case-by-case basis.

• Diabetes mellitus (DM). Type 2 DM, controlled with diet alone, or a history of isolated gestational diabetes are not exclusionary. Enrollment of individuals with Type 2 DM that is well-controlled on hypoglycemic agent(s) may be considered, provided the HgbA1c is ≤ 8% within the last 6 months (sites may draw these at screening).

• Previous or current recipient of an investigational HIV vaccine (previous placebo recipients are not excluded).

• Systemic glucocorticoid use equal to or greater than prednisone 10 mg/day within 3 months prior to enrollment, congenital or acquired immunodeficiency, or other systemic medication use likely to impair immune response to vaccine in the opinion of the site investigator.

• Blood products or immunoglobulin within 16 weeks prior to enrollment; receipt of immunoglobulin within 16 weeks prior to enrollment requires PSRT approval.

• Receipt of any live attenuated vaccine within 4 weeks prior to enrollment. (Note: ACAM2000 vaccine for Monkeypox received within 30 days prior to enrollment or receipt of study vaccine, or if ACAM2000 received greater than 30 days prior to enrollment, or prior to receipt of study vaccine and vaccination scab still present; or planned administration within 30 days after enrollment or receipt of study vaccine).

• Receipt of any vaccines that are not live attenuated within 14 days prior to enrollment; replication incompetent vaccines such as the Jynneos vaccine for the prevention of monkeypox disease are not considered to be live vaccines.

• Non-HIV experimental vaccine(s) received within the last 1 year in a prior vaccine trial. Exceptions may be made by the HVTN 305 PSRT for vaccines that have subsequently undergone licensure or Emergency Use Authorization by the FDA or, if outside the United States, equivalent authorization by the national regulatory authority.

• Initiation of antigen-based immunotherapy for allergies within the previous year (stable immunotherapy is not exclusionary); inclusion of participants who initiated immunotherapy within the previous year requires PSRT approval.

• Receipt of investigational research agents with a half-life of 7 or fewer days within 4 weeks prior to enrollment. If a potential participant has received investigational agents with a half-life greater than 7 days (or unknown half-life) within the past year, PSRT approval is required for enrollment.

• Serious reactions to vaccines that preclude receipt of study injections as determined by the principal investigator (PI) or designee, including history of serious reaction (eg, hypersensitivity, anaphylaxis) to any or any component of the study vaccine.

• Hereditary angioedema, acquired angioedema, or idiopathic forms of angioedema.

• Idiopathic urticaria within the past year.

• Bleeding disorder diagnosed by a doctor (eg, factor deficiency, coagulopathy, or platelet disorder requiring special precautions).

• Seizure disorder; febrile seizures as a child or seizures secondary to alcohol withdrawal more than 5 years ago are not exclusionary.

• Asplenia or functional asplenia.

• Active duty and reserve US military personnel.

• Any other chronic or clinically significant condition that in the clinical judgement of the investigator would jeopardize the safety or rights of the study participant, including, but not limited to: clinically significant forms of drug or alcohol abuse, serious psychiatric disorders, persons with any suicide attempt within the past one year (if between 1-2 years, consult PSRT) or cancer that, in the clinical judgment of the site investigator, has a potential for recurrence (excluding basal cell carcinoma).

• Asthma is excluded if the participant has ANY of the following:

  • Required either oral or parenteral corticosteroids for an exacerbation two or more times within the past year; OR
  • Required either oral or parenteral corticosteroids for an exacerbation 2 or more times within the past year; OR
  • Needed emergency care, urgent care, hospitalization, or intubation for an acute asthma exacerbation within the past year (eg, would NOT exclude individuals with asthma who meet all other criteria but sought urgent/emergent care solely for asthma medication refills or coexisting conditions unrelated to asthma); OR
  • Uses a short-acting rescue inhaler more than 2 days per week for acute asthma symptoms (ie, not for preventive treatment prior to athletic activity); OR
  • Uses medium-to-high-dose inhaled corticosteroids (greater than 250 mcg fluticasone or therapeutic equivalent per day), whether in single-therapy or dual-therapy inhalers (ie, with a long-acting beta agonist [LABA]); OR
  • Uses more than 1 medication for maintenance therapy daily. Inclusion of anyone on a stable dose of more than 1 medication for maintenance therapy daily for greater than 2 years requires PSRT approval.

• A participant with a history of an immune-mediated disease, either active or remote. Specific examples are listed in Appendix I (AESI index). Not exclusionary: 1) remote history of Bell's palsy (>2 years ago) not associated with other neurologic symptoms, 2) mild psoriasis that does not require ongoing systemic treatment.

• History of allergy to local anesthetic (Novocaine, Lidocaine).

• Investigator concern for difficulty with venous access based upon clinical history and physical examination. For example, history of IV drug abuse or substantial difficulty with previous blood draws.

• Presence of implanted electronic medical device (eg, pacemaker, implantable cardioverter defibrillator).

• Presence of surgical or traumatic metal implant in either upper arm and/or upper torso.

• History of cardiac arrhythmia (eg, supraventricular tachycardia, atrial fibrillation) (Not excluded: sinus arrhythmia).

• Tattoo overlying the injection sites preventing assessment of reactogenicity in the view of the investigator or skin condition at the injection sites.

• History or presence of keloid scar formation or hypertrophic scar