Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed GD2 positive tumors which include:

- High risk neuroblastoma (stage IV, or N-myc amplified, or localized
neuroblastoma multiply recurrent)

- Recurrent or metastatic osteosarcoma

- Recurrent or metastatic GD2 positive sarcomas

- If free of disease, patient must be fully recovered from toxic effects or
complications of prior treatments (chemotherapy or surgery)

- No greater than 6 months since last chemotherapy or surgery before first
injection of A1G4

PATIENT CHARACTERISTICS:

Age:

- Any age

Performance status:

- Not specified

Life expectancy:

- At least 6 months

Hematopoietic:

- Absolute neutrophil count greater than 500/mm^3

- Absolute leukocyte count greater than 500/mm^3

- Peripheral T-cell phytohemagglutinin activation (PHA) at least 50% of normal

Hepatic:

- Not specified

Renal:

- Not specified

Cardiovascular:

- No significant heart disease (NYHA class III or IV)

Other:

- No other serious intercurrent illnesses

- No active infections requiring antibiotics

- No active bleeding

- No primary immunodeficiency

- Not pregnant or nursing

- Adequate contraception required of all fertile patients

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- No concurrent antibiotics

- No prior mouse antibodies and detectable human antimouse antibody (HAMA) titer

Chemotherapy:

- See Disease Characteristics

- At least 6 weeks since nitrosoureas

- At least 4 weeks since other systemic chemotherapy

Endocrine therapy:

- No concurrent nonsteroidal anti-inflammatory agents

- No concurrent corticosteroid

Radiotherapy:

- At least 4 weeks since radiotherapy

- No prior radiation therapy to the spleen

Surgery:

- See Disease Characteristics

- No splenectomy