Inclusion Criteria

Patients must have:

• Documented HIV infection.
• CD4+ cell count between 300 and 500 cells/mm3.
• HIV-1 RNA < 500 by the branched-chain DNA assay (bDNA assay, Chiron) within 21 days of study entry [AS

PER AMENDMENT 11/25/98:

• Undetectable-plasma HIV titers (as defined by the FDA) by the branched-chain DNA test].
• Established B cell lines [deleted AS PER AMENDMENT 11/25/98].
• Response to at least one recall antigen in an in vitro assay of lymphocyte proliferative responses.
• Life expectancy > 6 months [deleted AS PER AMENDMENT 11/25/98].

Exclusion Criteria

Co-existing Condition:

Patients with the following conditions or symptoms are excluded:

• Active opportunistic infection or HIV-related malignancy [HIV-related malignancy deleted AS PER AMENDMENT 11/25/98].
• Peripheral neuropathy of grade 2 or higher by Division of AIDS toxicity criteria.

Concurrent Medication:

Excluded:

• Other investigational HIV-drugs.
• Immunomodulatory or potentially immunomodulatory drugs, such as glucocorticoids, hematopoietins, interleukin-2, interferon, or pentoxifylline.

Patients with the following prior conditions are excluded:

History of serious hypersensitivity to tetanus toxoid or any of the vaccine components.

Prior Medication:

Excluded:

• Previous immunization with pneumococcal polysaccharide vaccine [or, AS PER AMENDMENT 11/25/98, keyhole limpet hemocyanin vaccine].
• Tetanus toxoid booster within 5 years [deleted AS PER AMENDMENT 11/25/98].
• Other investigational HIV-drugs within 6 weeks of enrollment.
• Immunomodulatory or potentially immunomodulatory drugs, such as glucocorticoids, hematopoietins, interleukin-2, interferon, or pentoxifylline within 6 weeks of enrollment.

Risk Behavior:

Excluded:

Active drug or alcohol abuse.

Required:

Effective combination antiretroviral therapy including two nucleoside analog agents (ZDV, 3TC, ddI, ddC, or d4T) and nelfinavir or indinavir, for at least one month prior to study entry. [AS PER AMENDMENT 11/25/98:

• On stable, effective, highly-active antiretroviral therapy with combinations of any FDA-approved anti-HIV drugs for at least 3 months prior to entry.]